AI Trajectory

null

{
  "EnableConfigs": [
    "NET_IPGRE",
    "NET_IPGRE_DEMUX",
    "IPV6_GRE"
  ],
  "FocusSymbols": [
    "ipgre_xmit",
    "erspan_xmit",
    "gre_tap_xmit",
    "ip6erspan_tunnel_xmit",
    "ipgre_fill_info",
    "erspan_fill_info",
    "ip6gre_fill_info"
  ],
  "KMSANReasoning": "The patch fixes a concurrency and logic bug where shared tunnel parameters (`tunnel-\u003eparms.o_flags`) were being incorrectly modified during packet transmission (`erspan_xmit`, `ip6erspan_tunnel_xmit`) and netlink dumps (`ipgre_fill_info`, `erspan_fill_info`). This could lead to data races and corrupted tunnel state. The fix introduces local copies of the flags (`IP_TUNNEL_DECLARE_FLAGS`) which are fully initialized via `ip_tunnel_flags_copy()` (which uses `bitmap_copy()` to copy the entire `unsigned long` array). There is no introduction of uninitialized memory, nor any risk of info-leaks to user space. Standard KASAN/KCSAN and logic testing are sufficient to catch data races and memory corruption. KMSAN is specifically for uninitialized memory and is not applicable here.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch modifies the transmission and netlink info dumping paths for GRE and ERSPAN tunnels over IPv4 and IPv6. It fixes an issue where the tunnel's output flags (`tunnel-\u003eparms.o_flags`) were being modified during transmission or netlink dumps, which could lead to race conditions or unintended state changes. These are core networking functions reachable via standard network traffic and netlink configuration, so they are worth fuzzing.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit 619eb157817341039c15cb6977f4388e2bfa5de1\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Wed Aug 12 16:10:19 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c\nindex 6a92607401e8a..82309efd417e0 100644\n--- a/net/ipv4/ip_gre.c\n+++ b/net/ipv4/ip_gre.c\n@@ -475,12 +475,9 @@ static int gre_rcv(struct sk_buff *skb)\n \n static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,\n \t\t       const struct iphdr *tnl_params,\n-\t\t       __be16 proto)\n+\t\t       __be16 proto, const unsigned long *flags)\n {\n \tstruct ip_tunnel *tunnel = netdev_priv(dev);\n-\tIP_TUNNEL_DECLARE_FLAGS(flags);\n-\n-\tip_tunnel_flags_copy(flags, tunnel-\u003eparms.o_flags);\n \n \t/* Push GRE header. */\n \tgre_build_header(skb, tunnel-\u003etun_hlen,\n@@ -653,6 +650,7 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,\n \t\t\t      struct net_device *dev)\n {\n \tstruct ip_tunnel *tunnel = netdev_priv(dev);\n+\tIP_TUNNEL_DECLARE_FLAGS(flags);\n \tconst struct iphdr *tnl_params;\n \n \tif (!pskb_inet_may_pull(skb))\n@@ -688,11 +686,12 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,\n \t\ttnl_params = \u0026tunnel-\u003eparms.iph;\n \t}\n \n-\tif (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,\n-\t\t\t\t\t      tunnel-\u003eparms.o_flags)))\n+\tip_tunnel_flags_copy(flags, tunnel-\u003eparms.o_flags);\n+\n+\tif (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, flags)))\n \t\tgoto free_skb;\n \n-\t__gre_xmit(skb, dev, tnl_params, skb-\u003eprotocol);\n+\t__gre_xmit(skb, dev, tnl_params, skb-\u003eprotocol, flags);\n \treturn NETDEV_TX_OK;\n \n free_skb:\n@@ -705,6 +704,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,\n \t\t\t       struct net_device *dev)\n {\n \tstruct ip_tunnel *tunnel = netdev_priv(dev);\n+\tIP_TUNNEL_DECLARE_FLAGS(flags);\n \tbool truncate = false;\n \t__be16 proto;\n \n@@ -728,10 +728,12 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,\n \t\ttruncate = true;\n \t}\n \n+\tip_tunnel_flags_copy(flags, tunnel-\u003eparms.o_flags);\n+\n \t/* Push ERSPAN header */\n \tif (tunnel-\u003eerspan_ver == 0) {\n \t\tproto = htons(ETH_P_ERSPAN);\n-\t\t__clear_bit(IP_TUNNEL_SEQ_BIT, tunnel-\u003eparms.o_flags);\n+\t\t__clear_bit(IP_TUNNEL_SEQ_BIT, flags);\n \t} else if (tunnel-\u003eerspan_ver == 1) {\n \t\terspan_build_header(skb, ntohl(tunnel-\u003eparms.o_key),\n \t\t\t\t    tunnel-\u003eindex,\n@@ -746,8 +748,8 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,\n \t\tgoto free_skb;\n \t}\n \n-\t__clear_bit(IP_TUNNEL_KEY_BIT, tunnel-\u003eparms.o_flags);\n-\t__gre_xmit(skb, dev, \u0026tunnel-\u003eparms.iph, proto);\n+\t__clear_bit(IP_TUNNEL_KEY_BIT, flags);\n+\t__gre_xmit(skb, dev, \u0026tunnel-\u003eparms.iph, proto, flags);\n \treturn NETDEV_TX_OK;\n \n free_skb:\n@@ -760,6 +762,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,\n \t\t\t\tstruct net_device *dev)\n {\n \tstruct ip_tunnel *tunnel = netdev_priv(dev);\n+\tIP_TUNNEL_DECLARE_FLAGS(flags);\n \n \tif (!pskb_inet_may_pull(skb))\n \t\tgoto free_skb;\n@@ -769,14 +772,15 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,\n \t\treturn NETDEV_TX_OK;\n \t}\n \n-\tif (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,\n-\t\t\t\t\t      tunnel-\u003eparms.o_flags)))\n+\tip_tunnel_flags_copy(flags, tunnel-\u003eparms.o_flags);\n+\n+\tif (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, flags)))\n \t\tgoto free_skb;\n \n \tif (skb_cow_head(skb, dev-\u003eneeded_headroom))\n \t\tgoto free_skb;\n \n-\t__gre_xmit(skb, dev, \u0026tunnel-\u003eparms.iph, htons(ETH_P_TEB));\n+\t__gre_xmit(skb, dev, \u0026tunnel-\u003eparms.iph, htons(ETH_P_TEB), flags);\n \treturn NETDEV_TX_OK;\n \n free_skb:\n@@ -1560,12 +1564,15 @@ static size_t ipgre_get_size(const struct net_device *dev)\n \n static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)\n {\n-\tstruct ip_tunnel *t = netdev_priv(dev);\n-\tstruct ip_tunnel_parm_kern *p = \u0026t-\u003eparms;\n+\tconst struct ip_tunnel *t = netdev_priv(dev);\n+\tconst struct ip_tunnel_parm_kern *p = \u0026t-\u003eparms;\n \tIP_TUNNEL_DECLARE_FLAGS(o_flags);\n \n \tip_tunnel_flags_copy(o_flags, p-\u003eo_flags);\n \n+\tif (t-\u003eerspan_ver != 0 \u0026\u0026 !t-\u003ecollect_md)\n+\t\t__set_bit(IP_TUNNEL_KEY_BIT, o_flags);\n+\n \tif (nla_put_u32(skb, IFLA_GRE_LINK, p-\u003elink) ||\n \t    nla_put_be16(skb, IFLA_GRE_IFLAGS,\n \t\t\t gre_tnl_flags_to_gre_flags(p-\u003ei_flags)) ||\n@@ -1608,12 +1615,9 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)\n \n static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)\n {\n-\tstruct ip_tunnel *t = netdev_priv(dev);\n+\tconst struct ip_tunnel *t = netdev_priv(dev);\n \n \tif (t-\u003eerspan_ver \u003c= 2) {\n-\t\tif (t-\u003eerspan_ver != 0 \u0026\u0026 !t-\u003ecollect_md)\n-\t\t\t__set_bit(IP_TUNNEL_KEY_BIT, t-\u003eparms.o_flags);\n-\n \t\tif (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t-\u003eerspan_ver))\n \t\t\tgoto nla_put_failure;\n \ndiff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c\nindex b843116e9b703..0b3f386b51a2d 100644\n--- a/net/ipv6/ip6_gre.c\n+++ b/net/ipv6/ip6_gre.c\n@@ -964,7 +964,6 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,\n \tif (skb_cow_head(skb, dev-\u003eneeded_headroom ?: t-\u003ehlen))\n \t\tgoto tx_err;\n \n-\t__clear_bit(IP_TUNNEL_KEY_BIT, t-\u003eparms.o_flags);\n \tIPCB(skb)-\u003eflags = 0;\n \n \t/* For collect_md mode, derive fl6 from the tunnel key,\n@@ -2115,8 +2114,8 @@ static size_t ip6gre_get_size(const struct net_device *dev)\n \n static int ip6gre_fill_info(struct sk_buff *skb, const struct net_device *dev)\n {\n-\tstruct ip6_tnl *t = netdev_priv(dev);\n-\tstruct __ip6_tnl_parm *p = \u0026t-\u003eparms;\n+\tconst struct ip6_tnl *t = netdev_priv(dev);\n+\tconst struct __ip6_tnl_parm *p = \u0026t-\u003eparms;\n \tIP_TUNNEL_DECLARE_FLAGS(o_flags);\n \n \tip_tunnel_flags_copy(o_flags, p-\u003eo_flags);\n"
}

best-expensive

null

{
  "EnableConfigs": [
    "NET_IPGRE",
    "NET_IPGRE_DEMUX",
    "IPV6_GRE"
  ],
  "FocusSymbols": [
    "ipgre_xmit",
    "erspan_xmit",
    "gre_tap_xmit",
    "ip6erspan_tunnel_xmit",
    "ipgre_fill_info",
    "erspan_fill_info",
    "ip6gre_fill_info"
  ],
  "Reasoning": "The patch modifies the transmission and netlink info dumping paths for GRE and ERSPAN tunnels over IPv4 and IPv6. It fixes an issue where the tunnel's output flags (`tunnel-\u003eparms.o_flags`) were being modified during transmission or netlink dumps, which could lead to race conditions or unintended state changes. These are core networking functions reachable via standard network traffic and netlink configuration, so they are worth fuzzing.",
  "WorthFuzzing": true
}

You are an expert Linux kernel maintainer.
Your job is to review a provided patch series and determine
if it makes functional changes to the kernel that should be fuzzed.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively
use your code access tools to examine the actual source code and confirm any assumptions.

Return WorthFuzzing=false if the patch only contains:
- Modifications to Documentation/, Kconfig files, or code comments.
- Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints.
- Changes to numeric constants or macros that do not functionally alter execution flow.
- Code paths that are impossible to reach in virtualized environments like GCE or QEMU,
  even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim).
- Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed,
  ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU.
- Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove)
  that are executed only during PCI hot-unplug or sysfs driver unbind operations.

If it modifies reachable core kernel logic, drivers, or architectures, use your code search
tools to verify the code can be executed, then return WorthFuzzing=true.

When returning WorthFuzzing=true, you MUST ALSO:
1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols.
   Avoid listing generic hot-path functions to prevent skewed test distributions.
   Prefer non-static, non-inlined API entrypoint functions over internal static helper functions
   (which are inlined by the compiler and do not have distinct symbol addresses).
2. Identify any specific CONFIG_ options required to properly test this new/modified feature.
   Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions.
   Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs
   needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs
   output array, and DO NOT add a 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

For your convenience, here is the diff of the changes:
commit 619eb157817341039c15cb6977f4388e2bfa5de1
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Aug 12 16:10:19 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 6a92607401e8a..82309efd417e0 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -475,12 +475,9 @@ static int gre_rcv(struct sk_buff *skb)
 
 static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 		       const struct iphdr *tnl_params,
-		       __be16 proto)
+		       __be16 proto, const unsigned long *flags)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	IP_TUNNEL_DECLARE_FLAGS(flags);
-
-	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
 
 	/* Push GRE header. */
 	gre_build_header(skb, tunnel->tun_hlen,
@@ -653,6 +650,7 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
 			      struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 	const struct iphdr *tnl_params;
 
 	if (!pskb_inet_may_pull(skb))
@@ -688,11 +686,12 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
 		tnl_params = &tunnel->parms.iph;
 	}
 
-	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
-					      tunnel->parms.o_flags)))
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
+
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, flags)))
 		goto free_skb;
 
-	__gre_xmit(skb, dev, tnl_params, skb->protocol);
+	__gre_xmit(skb, dev, tnl_params, skb->protocol, flags);
 	return NETDEV_TX_OK;
 
 free_skb:
@@ -705,6 +704,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 			       struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 	bool truncate = false;
 	__be16 proto;
 
@@ -728,10 +728,12 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 		truncate = true;
 	}
 
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
+
 	/* Push ERSPAN header */
 	if (tunnel->erspan_ver == 0) {
 		proto = htons(ETH_P_ERSPAN);
-		__clear_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags);
+		__clear_bit(IP_TUNNEL_SEQ_BIT, flags);
 	} else if (tunnel->erspan_ver == 1) {
 		erspan_build_header(skb, ntohl(tunnel->parms.o_key),
 				    tunnel->index,
@@ -746,8 +748,8 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 		goto free_skb;
 	}
 
-	__clear_bit(IP_TUNNEL_KEY_BIT, tunnel->parms.o_flags);
-	__gre_xmit(skb, dev, &tunnel->parms.iph, proto);
+	__clear_bit(IP_TUNNEL_KEY_BIT, flags);
+	__gre_xmit(skb, dev, &tunnel->parms.iph, proto, flags);
 	return NETDEV_TX_OK;
 
 free_skb:
@@ -760,6 +762,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
 				struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 
 	if (!pskb_inet_may_pull(skb))
 		goto free_skb;
@@ -769,14 +772,15 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
 		return NETDEV_TX_OK;
 	}
 
-	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
-					      tunnel->parms.o_flags)))
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
+
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, flags)))
 		goto free_skb;
 
 	if (skb_cow_head(skb, dev->needed_headroom))
 		goto free_skb;
 
-	__gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB));
+	__gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB), flags);
 	return NETDEV_TX_OK;
 
 free_skb:
@@ -1560,12 +1564,15 @@ static size_t ipgre_get_size(const struct net_device *dev)
 
 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct ip_tunnel *t = netdev_priv(dev);
-	struct ip_tunnel_parm_kern *p = &t->parms;
+	const struct ip_tunnel *t = netdev_priv(dev);
+	const struct ip_tunnel_parm_kern *p = &t->parms;
 	IP_TUNNEL_DECLARE_FLAGS(o_flags);
 
 	ip_tunnel_flags_copy(o_flags, p->o_flags);
 
+	if (t->erspan_ver != 0 && !t->collect_md)
+		__set_bit(IP_TUNNEL_KEY_BIT, o_flags);
+
 	if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
 	    nla_put_be16(skb, IFLA_GRE_IFLAGS,
 			 gre_tnl_flags_to_gre_flags(p->i_flags)) ||
@@ -1608,12 +1615,9 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 
 static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct ip_tunnel *t = netdev_priv(dev);
+	const struct ip_tunnel *t = netdev_priv(dev);
 
 	if (t->erspan_ver <= 2) {
-		if (t->erspan_ver != 0 && !t->collect_md)
-			__set_bit(IP_TUNNEL_KEY_BIT, t->parms.o_flags);
-
 		if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
 			goto nla_put_failure;
 
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index b843116e9b703..0b3f386b51a2d 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -964,7 +964,6 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
 	if (skb_cow_head(skb, dev->needed_headroom ?: t->hlen))
 		goto tx_err;
 
-	__clear_bit(IP_TUNNEL_KEY_BIT, t->parms.o_flags);
 	IPCB(skb)->flags = 0;
 
 	/* For collect_md mode, derive fl6 from the tunnel key,
@@ -2115,8 +2114,8 @@ static size_t ip6gre_get_size(const struct net_device *dev)
 
 static int ip6gre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct ip6_tnl *t = netdev_priv(dev);
-	struct __ip6_tnl_parm *p = &t->parms;
+	const struct ip6_tnl *t = netdev_priv(dev);
+	const struct __ip6_tnl_parm *p = &t->parms;
 	IP_TUNNEL_DECLARE_FLAGS(o_flags);
 
 	ip_tunnel_flags_copy(o_flags, p->o_flags);

gemini-3.1-pro-preview

null

null

							input: 4220
							output: 29
							thoughts: 460
						

**Analyzing a GRE/ERSPAN Tunnel Flag Modification**

Okay, so this patch is clearly targeted at `net/ipv4/ip_gre.c` and `net/ipv6/ip6_gre.c`, specifically how tunnel flags are handled in GRE and ERSPAN tunnels. The core of the change seems to be about avoiding modifications to `tunnel->parms.o_flags` during critical transmission phases, namely in `erspan_xmit` and `ip6erspan_tunnel_xmit`. Instead of directly messing with that global, they're using a local `flags` copy which gets passed to `__gre_xmit`. Smart. This also involves fixing `erspan_fill_info` and `ipgre_fill_info` to ensure they don't corrupt `t->parms.o_flags` when dumping netlink info.

Functionally, this smells like a race condition prevention or a fix for unintended state changes in `tunnel->parms.o_flags`. That's definitely worth paying attention to. Let's list the modified functions to be sure:

In `net/ipv4/ip_gre.c`: `__gre_xmit`, `ipgre_xmit`, `erspan_xmit`, `gre_tap_xmit`, `ipgre_fill_info`, and `erspan_fill_info`.

And in `net/ipv6/ip6_gre.c`: `ip6erspan_tunnel_xmit` and `ip6gre_fill_info`.

Yep, these are all reachable core networking functions, concerning GRE and ERSPAN tunnels. I'd consider this significant enough to flag it as potentially vulnerable. My immediate inclination is to assign `WorthFuzzing=true`.

Let's keep these symbols in focus: `ipgre_xmit`, `erspan_xmit`, `gre_tap_xmit`, `ip6erspan_tunnel_xmit`, `ipgre_fill_info`, `erspan_fill_info`, and `ip6gre_fill_info`.

Now, before I green-light this fully, I need to check the required configurations. `net/ipv4/ip_gre.c` is compiled when `CONFIG_NET_IPGRE` is enabled, and `net/ipv6/ip6_gre.c` needs `CONFIG_IPV6_GRE`. Okay, I need to verify those config options are set.

{
  "Expression": "NET_IPGRE",
  "PathPrefix": "net/ipv4/"
}

{
  "Output": "net/ipv4/Kconfig=162=config NET_IPIP\n--\nnet/ipv4/Kconfig-179-\nnet/ipv4/Kconfig:180:config NET_IPGRE_DEMUX\nnet/ipv4/Kconfig-181-\ttristate \"IP: GRE demultiplexer\"\n--\nnet/ipv4/Kconfig=186=config NET_IP_TUNNEL\n--\nnet/ipv4/Kconfig-191-\nnet/ipv4/Kconfig:192:config NET_IPGRE\nnet/ipv4/Kconfig-193-\ttristate \"IP: GRE tunnels over IP\"\nnet/ipv4/Kconfig:194:\tdepends on NET_IPGRE_DEMUX\nnet/ipv4/Kconfig-195-\tselect NET_IP_TUNNEL\n--\nnet/ipv4/Kconfig-206-\nnet/ipv4/Kconfig:207:config NET_IPGRE_BROADCAST\nnet/ipv4/Kconfig-208-\tbool \"IP: broadcast GRE over IP\"\nnet/ipv4/Kconfig:209:\tdepends on IP_MULTICAST \u0026\u0026 NET_IPGRE\nnet/ipv4/Kconfig-210-\thelp\n--\nnet/ipv4/Kconfig=330=config NET_FOU_IP_TUNNELS\nnet/ipv4/Kconfig-331-\tbool \"IP: FOU encapsulation of IP tunnels\"\nnet/ipv4/Kconfig:332:\tdepends on NET_IPIP || NET_IPGRE || IPV6_SIT\nnet/ipv4/Kconfig-333-\tselect NET_FOU\n--\nnet/ipv4/Makefile=28=obj-$(CONFIG_NET_FOU) += fou.o\nnet/ipv4/Makefile:29:obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o\nnet/ipv4/Makefile:30:obj-$(CONFIG_NET_IPGRE) += ip_gre.o\nnet/ipv4/Makefile-31-udp_tunnel-y := udp_tunnel_core.o udp_tunnel_nic.o\n--\nnet/ipv4/ip_gre.c=440=static int gre_rcv(struct sk_buff *skb)\n--\nnet/ipv4/ip_gre.c-445-\nnet/ipv4/ip_gre.c:446:#ifdef CONFIG_NET_IPGRE_BROADCAST\nnet/ipv4/ip_gre.c-447-\tif (ipv4_is_multicast(ip_hdr(skb)-\u003edaddr)) {\n--\nnet/ipv4/ip_gre.c=935=static const struct header_ops ipgre_header_ops = {\n--\nnet/ipv4/ip_gre.c-939-\nnet/ipv4/ip_gre.c:940:#ifdef CONFIG_NET_IPGRE_BROADCAST\nnet/ipv4/ip_gre.c-941-static int ipgre_open(struct net_device *dev)\n--\nnet/ipv4/ip_gre.c=984=static const struct net_device_ops ipgre_netdev_ops = {\n--\nnet/ipv4/ip_gre.c-986-\t.ndo_uninit\t\t= ip_tunnel_uninit,\nnet/ipv4/ip_gre.c:987:#ifdef CONFIG_NET_IPGRE_BROADCAST\nnet/ipv4/ip_gre.c-988-\t.ndo_open\t\t= ipgre_open,\n--\nnet/ipv4/ip_gre.c=1040=static int ipgre_tunnel_init(struct net_device *dev)\n--\nnet/ipv4/ip_gre.c-1054-\tif (iph-\u003edaddr \u0026\u0026 !tunnel-\u003ecollect_md) {\nnet/ipv4/ip_gre.c:1055:#ifdef CONFIG_NET_IPGRE_BROADCAST\nnet/ipv4/ip_gre.c-1056-\t\tif (ipv4_is_multicast(iph-\u003edaddr)) {\n--\nnet/ipv4/ip_tunnel.c=377=int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,\n--\nnet/ipv4/ip_tunnel.c-383-\nnet/ipv4/ip_tunnel.c:384:#ifdef CONFIG_NET_IPGRE_BROADCAST\nnet/ipv4/ip_tunnel.c-385-\tif (ipv4_is_multicast(iph-\u003edaddr)) {\n"
}

gemini-3.1-pro-preview

null

null

							input: 6363
							output: 29
							thoughts: 32
						

Okay, here's my take on those networking configurations:

**Analyzing Network Configuration Requirements**

Alright, so the task at hand requires both `NET_IPGRE` and `NET_IPGRE_DEMUX`. That much is clear. The question now becomes: Do we need to consider IPv6 GRE as well? So, let's just confirm if `IPV6_GRE` is relevant to the solution.

{
  "Expression": "IPV6_GRE",
  "PathPrefix": "net/ipv6/"
}

{
  "Output": "net/ipv6/Kconfig=199=config IPV6_TUNNEL\n--\nnet/ipv6/Kconfig-209-\nnet/ipv6/Kconfig:210:config IPV6_GRE\nnet/ipv6/Kconfig-211-\ttristate \"IPv6: GRE tunnel\"\n--\nnet/ipv6/Makefile=42=obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o\nnet/ipv6/Makefile:43:obj-$(CONFIG_IPV6_GRE) += ip6_gre.o\nnet/ipv6/Makefile-44-obj-$(CONFIG_IPV6_FOU) += fou6.o\n"
}

gemini-3.1-pro-preview

null

null

							input: 6687
							output: 40
							thoughts: 842
						

**Analyzing GRE and ERSPAN Tunnel Transmission and Netlink Info Paths**

Okay, so I need to address the `IPV6_GRE` configuration here. My initial thought is to zero in on these functions: `ipgre_xmit`, `erspan_xmit`, `gre_tap_xmit`, `ip6erspan_tunnel_xmit`, `ipgre_fill_info`, `erspan_fill_info`, and `ip6gre_fill_info`. These seem like the key entry points for transmission and netlink info dumping within the GRE and ERSPAN tunnel implementations.

I quickly checked if these functions are static, which they are, but they are assigned to function pointers like `ndo_start_xmit` and `rtnl_link_ops->fill_info`. Given the instructions, I wanted to confirm that these aren't inlined because inlined functions don't have distinct symbol addresses, and that's not ideal for what I am trying to do here.

Okay, `ipgre_xmit`, `erspan_xmit`, `gre_tap_xmit`, and `ip6erspan_tunnel_xmit` are all assigned to `.ndo_start_xmit` in their respective netdev_ops structures. Likewise, `ipgre_fill_info`, `erspan_fill_info`, and `ip6gre_fill_info` are assigned to `.fill_info` within the corresponding link_ops structures. Given these assignments to function pointers, I can be confident that these functions are *not* inlined and do indeed have distinct symbol addresses. Perfect; that's exactly what I'm looking for.

I'll also make sure to cover the relevant configurations. It looks like `NET_IPGRE` depends on `NET_IPGRE_DEMUX`, and `IPV6_GRE` is contingent on `IPV6`. So, the necessary configs are: `NET_IPGRE`, `NET_IPGRE_DEMUX`, and `IPV6_GRE`.

I wanted to ensure I didn't miss anything. I spotted `__gre_xmit`, which *is* static and called by the `xmit` functions. Because it looks like it might be inlined, I'm going to exclude that from my list of focus symbols.

So, here's my reasoning. The main issue appears to be related to the modification of the tunnel's output flags (`tunnel->parms.o_flags`) during transmission or netlink dumps. That's a classic concurrency issue that's likely to cause all sorts of problems. These functions are critical for network transmission and configuration, making them prime targets for fuzzing. They represent the main avenues for data entering or exiting these GRE and ERSPAN tunnels.

In summary, the focus symbols are:
*   `ipgre_xmit`
*   `erspan_xmit`
*   `gre_tap_xmit`
*   `ip6erspan_tunnel_xmit`
*   `ipgre_fill_info`
*   `erspan_fill_info`
*   `ip6gre_fill_info`

And I'll need these configurations:
*   `NET_IPGRE`
*   `NET_IPGRE_DEMUX`
*   `IPV6_GRE`

Now I should go and check `ip6erspan_tunnel_xmit` in `net/ipv6/ip6_gre.c`.

{
  "Expression": "ip6erspan_tunnel_xmit",
  "PathPrefix": "net/ipv6/ip6_gre.c"
}

{
  "Output": "net/ipv6/ip6_gre.c=878=static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,\n--\nnet/ipv6/ip6_gre.c-916-\nnet/ipv6/ip6_gre.c:917:static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,\nnet/ipv6/ip6_gre.c-918-\t\t\t\t\t struct net_device *dev)\n--\nnet/ipv6/ip6_gre.c=1883=static const struct net_device_ops ip6erspan_netdev_ops = {\n--\nnet/ipv6/ip6_gre.c-1885-\t.ndo_uninit =\t\tip6erspan_tunnel_uninit,\nnet/ipv6/ip6_gre.c:1886:\t.ndo_start_xmit =\tip6erspan_tunnel_xmit,\nnet/ipv6/ip6_gre.c-1887-\t.ndo_set_mac_address =\teth_mac_addr,\n"
}

gemini-3.1-pro-preview

null

null

							input: 8603
							output: 35
							thoughts: 40
						

Okay, here's my take on those thoughts, framed as an expert's internal monologue:

**Investigating the Data Transmission Path**

Right, so the trace points to `.ndo_start_xmit`. That's where the packet transmission begins, so that’s a good starting point. Now, to understand how it's handled, I need to dig into `ipgre_xmit` within `net/ipv4/ip_gre.c`. I need to figure out how GRE encapsulation is happening and where this packet is in the transmission queue.

{
  "Expression": "ipgre_xmit",
  "PathPrefix": "net/ipv4/ip_gre.c"
}

{
  "Output": "net/ipv4/ip_gre.c=625=static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)\n--\nnet/ipv4/ip_gre.c-648-\nnet/ipv4/ip_gre.c:649:static netdev_tx_t ipgre_xmit(struct sk_buff *skb,\nnet/ipv4/ip_gre.c-650-\t\t\t      struct net_device *dev)\n--\nnet/ipv4/ip_gre.c=984=static const struct net_device_ops ipgre_netdev_ops = {\n--\nnet/ipv4/ip_gre.c-990-#endif\nnet/ipv4/ip_gre.c:991:\t.ndo_start_xmit\t\t= ipgre_xmit,\nnet/ipv4/ip_gre.c-992-\t.ndo_siocdevprivate\t= ip_tunnel_siocdevprivate,\n"
}

gemini-3.1-pro-preview

null

null

							input: 9051
							output: 35
							thoughts: 37
						

Okay, here's my take on those thoughts, framed as an expert's internal monologue:

**Investigating a Network Transmission Function**

Alright, so I'm on `.ndo_start_xmit`. Good. This is where the magic happens, where the kernel hands off packets for transmission. Now, where are we sending this? I need to understand the network path. Let's see... my initial instinct is to check `erspan_xmit` in `net/ipv4/ip_gre.c`. That's where I'd expect to find the ERSPAN encapsulation code. I'm guessing that's involved here given the context, and it's a good place to start digging into the packet handling flow. Let's trace this function and see how the packet is being formatted.

{
  "Expression": "erspan_xmit",
  "PathPrefix": "net/ipv4/ip_gre.c"
}

{
  "Output": "net/ipv4/ip_gre.c=649=static netdev_tx_t ipgre_xmit(struct sk_buff *skb,\n--\nnet/ipv4/ip_gre.c-702-\nnet/ipv4/ip_gre.c:703:static netdev_tx_t erspan_xmit(struct sk_buff *skb,\nnet/ipv4/ip_gre.c-704-\t\t\t       struct net_device *dev)\n--\nnet/ipv4/ip_gre.c=1375=static const struct net_device_ops erspan_netdev_ops = {\n--\nnet/ipv4/ip_gre.c-1377-\t.ndo_uninit\t\t= ip_tunnel_uninit,\nnet/ipv4/ip_gre.c:1378:\t.ndo_start_xmit\t\t= erspan_xmit,\nnet/ipv4/ip_gre.c-1379-\t.ndo_set_mac_address\t= eth_mac_addr,\n"
}

gemini-3.1-pro-preview

null

null

							input: 9560
							output: 36
							thoughts: 28
						

Okay, here's my take on those thoughts, tailored for an expert audience:

**Analyzing `gre_tap_xmit` in `net/ipv4/ip_gre.c`**

Yes, that's what I want to focus on. Right, let's drill down into `gre_tap_xmit`. I need to refresh my memory on the workings of this function within the GRE (Generic Routing Encapsulation) implementation, specifically looking at how the tap interface transmits packets. My immediate concern is probably related to a recent issue I have been working on that required me to dive into the kernel code.

{
  "Expression": "gre_tap_xmit",
  "PathPrefix": "net/ipv4/ip_gre.c"
}

{
  "Output": "net/ipv4/ip_gre.c=703=static netdev_tx_t erspan_xmit(struct sk_buff *skb,\n--\nnet/ipv4/ip_gre.c-760-\nnet/ipv4/ip_gre.c:761:static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,\nnet/ipv4/ip_gre.c-762-\t\t\t\tstruct net_device *dev)\n--\nnet/ipv4/ip_gre.c=1342=static const struct net_device_ops gre_tap_netdev_ops = {\n--\nnet/ipv4/ip_gre.c-1344-\t.ndo_uninit\t\t= ip_tunnel_uninit,\nnet/ipv4/ip_gre.c:1345:\t.ndo_start_xmit\t\t= gre_tap_xmit,\nnet/ipv4/ip_gre.c-1346-\t.ndo_set_mac_address \t= eth_mac_addr,\n"
}

gemini-3.1-pro-preview

null

null

							input: 10024
							output: 36
							thoughts: 28
						

Okay, here's my take on those thoughts, tailored for an expert audience:

**Analyzing the GRE Tunnel Fill Information Function**

Yes, that feels right, that's where I need to be. Let's dig into the `ipgre_fill_info` function within the `net/ipv4/ip_gre.c` file. I'm going to start with the fill info section as I suspect there are some parameters that I could investigate further. I'm looking for where we're populating the GRE tunnel information. I'll be looking for potential areas that could be influencing the behaviour of the system. I'll make sure to double-check that the parameters that are being used are correct.

{
  "Expression": "ipgre_fill_info",
  "PathPrefix": "net/ipv4/ip_gre.c"
}

{
  "Output": "net/ipv4/ip_gre.c=1517=static size_t ipgre_get_size(const struct net_device *dev)\n--\nnet/ipv4/ip_gre.c-1564-\nnet/ipv4/ip_gre.c:1565:static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)\nnet/ipv4/ip_gre.c-1566-{\n--\nnet/ipv4/ip_gre.c=1616=static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)\n--\nnet/ipv4/ip_gre.c-1634-\nnet/ipv4/ip_gre.c:1635:\treturn ipgre_fill_info(skb, dev);\nnet/ipv4/ip_gre.c-1636-\n--\nnet/ipv4/ip_gre.c=1678=static struct rtnl_link_ops ipgre_link_ops __read_mostly = {\n--\nnet/ipv4/ip_gre.c-1688-\t.get_size\t= ipgre_get_size,\nnet/ipv4/ip_gre.c:1689:\t.fill_info\t= ipgre_fill_info,\nnet/ipv4/ip_gre.c-1690-\t.get_link_net\t= ip_tunnel_get_link_net,\n--\nnet/ipv4/ip_gre.c=1693=static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {\n--\nnet/ipv4/ip_gre.c-1703-\t.get_size\t= ipgre_get_size,\nnet/ipv4/ip_gre.c:1704:\t.fill_info\t= ipgre_fill_info,\nnet/ipv4/ip_gre.c-1705-\t.get_link_net\t= ip_tunnel_get_link_net,\n"
}

gemini-3.1-pro-preview

null

null

							input: 10755
							output: 36
							thoughts: 28
						

Okay, here's my take on those thoughts, tailored for an expert audience:

**Analyzing `erspan_fill_info` in `net/ipv4/ip_gre.c`**

Yes. Okay, that's what I'm thinking too. Let's dig into that `erspan_fill_info` function within the IPv4 GRE implementation. I want to see how that's working. I'm especially interested in the nuances of how the ERSPAN header is populated. Is it efficient? Are there any potential gotchas with different ERSPAN modes or configurations? I'm anticipating some intricate bit manipulation in there, dealing with the Type III ERSPAN header, or perhaps some less-than-obvious interactions with the underlying network interfaces. I'll be looking for how it handles the flow-ID, session-ID, and other metadata fields. It's time to see what’s going on under the hood and assess the implementation.

{
  "Expression": "erspan_fill_info",
  "PathPrefix": "net/ipv4/ip_gre.c"
}

{
  "Output": "net/ipv4/ip_gre.c=1565=static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)\n--\nnet/ipv4/ip_gre.c-1615-\nnet/ipv4/ip_gre.c:1616:static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)\nnet/ipv4/ip_gre.c-1617-{\n--\nnet/ipv4/ip_gre.c=1708=static struct rtnl_link_ops erspan_link_ops __read_mostly = {\n--\nnet/ipv4/ip_gre.c-1718-\t.get_size\t= ipgre_get_size,\nnet/ipv4/ip_gre.c:1719:\t.fill_info\t= erspan_fill_info,\nnet/ipv4/ip_gre.c-1720-\t.get_link_net\t= ip_tunnel_get_link_net,\n"
}

gemini-3.1-pro-preview

null

null

							input: 11293
							output: 38
							thoughts: 30
						

Okay, here's my take on those thoughts, tailored for an expert audience:

**Analyzing the IPv6 GRE Information Filling Function**

Yes, that feels right. My gut says we need to delve into `ip6gre_fill_info` in `net/ipv6/ip6_gre.c`. Let's confirm my assumptions regarding the control path or a specific data structure. I want to understand how the GRE tunnel information is being populated with IPv6 data, specifically the nuances of this function and how it interfaces with the broader GRE infrastructure. I am focused on the specifics in this area.

{
  "Expression": "ip6gre_fill_info",
  "PathPrefix": "net/ipv6/ip6_gre.c"
}

{
  "Output": "net/ipv6/ip6_gre.c=2073=static size_t ip6gre_get_size(const struct net_device *dev)\n--\nnet/ipv6/ip6_gre.c-2114-\nnet/ipv6/ip6_gre.c:2115:static int ip6gre_fill_info(struct sk_buff *skb, const struct net_device *dev)\nnet/ipv6/ip6_gre.c-2116-{\n--\nnet/ipv6/ip6_gre.c=2288=static struct rtnl_link_ops ip6gre_link_ops __read_mostly = {\n--\nnet/ipv6/ip6_gre.c-2298-\t.get_size\t= ip6gre_get_size,\nnet/ipv6/ip6_gre.c:2299:\t.fill_info\t= ip6gre_fill_info,\nnet/ipv6/ip6_gre.c-2300-\t.get_link_net\t= ip6_tnl_get_link_net,\n--\nnet/ipv6/ip6_gre.c=2303=static struct rtnl_link_ops ip6gre_tap_ops __read_mostly = {\n--\nnet/ipv6/ip6_gre.c-2312-\t.get_size\t= ip6gre_get_size,\nnet/ipv6/ip6_gre.c:2313:\t.fill_info\t= ip6gre_fill_info,\nnet/ipv6/ip6_gre.c-2314-\t.get_link_net\t= ip6_tnl_get_link_net,\n--\nnet/ipv6/ip6_gre.c=2317=static struct rtnl_link_ops ip6erspan_tap_ops __read_mostly = {\n--\nnet/ipv6/ip6_gre.c-2326-\t.get_size\t= ip6gre_get_size,\nnet/ipv6/ip6_gre.c:2327:\t.fill_info\t= ip6gre_fill_info,\nnet/ipv6/ip6_gre.c-2328-\t.get_link_net\t= ip6_tnl_get_link_net,\n"
}

gemini-3.1-pro-preview

null

null

							input: 12064
							output: 206
							thoughts: 46
						

Okay, here's my interpretation of those thoughts, tailored for an expert audience, presented in the first person:

**Operationalizing the GRE Configuration**

Right. Confirmed, all the focus symbols, based on the current context, are valid options to work with. Specifically, I'm noting the implications of the existing configuration. I see that `NET_IPGRE`, `NET_IPGRE_DEMUX`, and `IPV6_GRE` are enabled. This signals a setup geared towards encapsulating traffic with GRE, potentially for tunneling IPv4 and IPv6. Given the current information, there's no inherent conflict in using these, so I'll execute the next logical step. I'm going to call `set-results`.

{
  "EnableConfigs": [
    "NET_IPGRE",
    "NET_IPGRE_DEMUX",
    "IPV6_GRE"
  ],
  "FocusSymbols": [
    "ipgre_xmit",
    "erspan_xmit",
    "gre_tap_xmit",
    "ip6erspan_tunnel_xmit",
    "ipgre_fill_info",
    "erspan_fill_info",
    "ip6gre_fill_info"
  ],
  "Reasoning": "The patch modifies the transmission and netlink info dumping paths for GRE and ERSPAN tunnels over IPv4 and IPv6. It fixes an issue where the tunnel's output flags (`tunnel-\u003eparms.o_flags`) were being modified during transmission or netlink dumps, which could lead to race conditions or unintended state changes. These are core networking functions reachable via standard network traffic and netlink configuration, so they are worth fuzzing.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "NET_IPGRE",
    "NET_IPGRE_DEMUX",
    "IPV6_GRE"
  ],
  "FocusSymbols": [
    "ipgre_xmit",
    "erspan_xmit",
    "gre_tap_xmit",
    "ip6erspan_tunnel_xmit",
    "ipgre_fill_info",
    "erspan_fill_info",
    "ip6gre_fill_info"
  ],
  "Reasoning": "The patch modifies the transmission and netlink info dumping paths for GRE and ERSPAN tunnels over IPv4 and IPv6. It fixes an issue where the tunnel's output flags (`tunnel-\u003eparms.o_flags`) were being modified during transmission or netlink dumps, which could lead to race conditions or unintended state changes. These are core networking functions reachable via standard network traffic and netlink configuration, so they are worth fuzzing.",
  "WorthFuzzing": true
}

{
  "WorthFuzzing": true
}

null

best-expensive

null

{
  "KMSANReasoning": "The patch fixes a concurrency and logic bug where shared tunnel parameters (`tunnel-\u003eparms.o_flags`) were being incorrectly modified during packet transmission (`erspan_xmit`, `ip6erspan_tunnel_xmit`) and netlink dumps (`ipgre_fill_info`, `erspan_fill_info`). This could lead to data races and corrupted tunnel state. The fix introduces local copies of the flags (`IP_TUNNEL_DECLARE_FLAGS`) which are fully initialized via `ip_tunnel_flags_copy()` (which uses `bitmap_copy()` to copy the entire `unsigned long` array). There is no introduction of uninitialized memory, nor any risk of info-leaks to user space. Standard KASAN/KCSAN and logic testing are sufficient to catch data races and memory corruption. KMSAN is specifically for uninitialized memory and is not applicable here.",
  "NeedsKMSAN": false
}

You are an expert Linux kernel security engineer specializing in kernel memory
error detectors (KASAN and KMSAN). Your job is to review the provided patch series and
determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer)
fuzzing session in addition to standard KASAN fuzzing.

CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN:
- Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable
  a comprehensive suite of debugging tools and sanitizers, including KASAN
  (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP
  (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks.
- KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap,
  or page allocations) and kernel-to-user memory info-leaks.

Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN,
LOCKDEP, OR OTHER STANDARD BUG DETECTORS.
A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY
set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks
that are detected ONLY by KMSAN.

Look holistically at the patch series and surrounding code. Even if no direct
uninitialized field accesses or new buffer allocations are added in the diff itself,
a patch may alter control flow, bounds checking, or data length calculations in ways
that change how the rest of the code operates on existing buffers (e.g. allowing
uninitialized stack/heap memory to be read, copied to user space, or used in control
flow). Do not hesitate to use your code access tools to inspect the surrounding code,
called functions, and callers.

Set NeedsKMSAN=true ONLY IF the patch introduces or modifies:
1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb
   attributes, ioctl output arguments, socket options, or BPF buffers) where fields
   or structure padding might not be fully initialized/zeroed.
2. Conditional logic or branching that depends on potentially uninitialized variables
   or struct fields.
3. Allocation or initialization of complex data structures where uninitialized fields
   could be read later in reachable code paths.
4. Bounds checks, lengths, or logic in a way that allows surrounding code to access
   uninitialized bytes of existing buffers.

Set NeedsKMSAN=false IF:
- The code changes primarily risk out-of-bounds access, array overflows, NULL pointer
  dereferences, locking deadlocks, or use-after-free bugs (these are already caught
  by KASAN, LOCKDEP, or standard bug detectors).
- All stack/heap structures touched or introduced by the patch are fully zeroed
  or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied.
- The patch does not introduce any risk of uninitialized memory usage or info-leaks.

Use your code access tools to inspect the surrounding code if necessary, then provide
detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch.
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

For your convenience, here is the diff of the changes:
commit 619eb157817341039c15cb6977f4388e2bfa5de1
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Aug 12 16:10:19 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 6a92607401e8a..82309efd417e0 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -475,12 +475,9 @@ static int gre_rcv(struct sk_buff *skb)
 
 static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 		       const struct iphdr *tnl_params,
-		       __be16 proto)
+		       __be16 proto, const unsigned long *flags)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	IP_TUNNEL_DECLARE_FLAGS(flags);
-
-	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
 
 	/* Push GRE header. */
 	gre_build_header(skb, tunnel->tun_hlen,
@@ -653,6 +650,7 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
 			      struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 	const struct iphdr *tnl_params;
 
 	if (!pskb_inet_may_pull(skb))
@@ -688,11 +686,12 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
 		tnl_params = &tunnel->parms.iph;
 	}
 
-	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
-					      tunnel->parms.o_flags)))
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
+
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, flags)))
 		goto free_skb;
 
-	__gre_xmit(skb, dev, tnl_params, skb->protocol);
+	__gre_xmit(skb, dev, tnl_params, skb->protocol, flags);
 	return NETDEV_TX_OK;
 
 free_skb:
@@ -705,6 +704,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 			       struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 	bool truncate = false;
 	__be16 proto;
 
@@ -728,10 +728,12 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 		truncate = true;
 	}
 
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
+
 	/* Push ERSPAN header */
 	if (tunnel->erspan_ver == 0) {
 		proto = htons(ETH_P_ERSPAN);
-		__clear_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags);
+		__clear_bit(IP_TUNNEL_SEQ_BIT, flags);
 	} else if (tunnel->erspan_ver == 1) {
 		erspan_build_header(skb, ntohl(tunnel->parms.o_key),
 				    tunnel->index,
@@ -746,8 +748,8 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 		goto free_skb;
 	}
 
-	__clear_bit(IP_TUNNEL_KEY_BIT, tunnel->parms.o_flags);
-	__gre_xmit(skb, dev, &tunnel->parms.iph, proto);
+	__clear_bit(IP_TUNNEL_KEY_BIT, flags);
+	__gre_xmit(skb, dev, &tunnel->parms.iph, proto, flags);
 	return NETDEV_TX_OK;
 
 free_skb:
@@ -760,6 +762,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
 				struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 
 	if (!pskb_inet_may_pull(skb))
 		goto free_skb;
@@ -769,14 +772,15 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
 		return NETDEV_TX_OK;
 	}
 
-	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
-					      tunnel->parms.o_flags)))
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
+
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, flags)))
 		goto free_skb;
 
 	if (skb_cow_head(skb, dev->needed_headroom))
 		goto free_skb;
 
-	__gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB));
+	__gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB), flags);
 	return NETDEV_TX_OK;
 
 free_skb:
@@ -1560,12 +1564,15 @@ static size_t ipgre_get_size(const struct net_device *dev)
 
 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct ip_tunnel *t = netdev_priv(dev);
-	struct ip_tunnel_parm_kern *p = &t->parms;
+	const struct ip_tunnel *t = netdev_priv(dev);
+	const struct ip_tunnel_parm_kern *p = &t->parms;
 	IP_TUNNEL_DECLARE_FLAGS(o_flags);
 
 	ip_tunnel_flags_copy(o_flags, p->o_flags);
 
+	if (t->erspan_ver != 0 && !t->collect_md)
+		__set_bit(IP_TUNNEL_KEY_BIT, o_flags);
+
 	if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
 	    nla_put_be16(skb, IFLA_GRE_IFLAGS,
 			 gre_tnl_flags_to_gre_flags(p->i_flags)) ||
@@ -1608,12 +1615,9 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 
 static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct ip_tunnel *t = netdev_priv(dev);
+	const struct ip_tunnel *t = netdev_priv(dev);
 
 	if (t->erspan_ver <= 2) {
-		if (t->erspan_ver != 0 && !t->collect_md)
-			__set_bit(IP_TUNNEL_KEY_BIT, t->parms.o_flags);
-
 		if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
 			goto nla_put_failure;
 
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index b843116e9b703..0b3f386b51a2d 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -964,7 +964,6 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
 	if (skb_cow_head(skb, dev->needed_headroom ?: t->hlen))
 		goto tx_err;
 
-	__clear_bit(IP_TUNNEL_KEY_BIT, t->parms.o_flags);
 	IPCB(skb)->flags = 0;
 
 	/* For collect_md mode, derive fl6 from the tunnel key,
@@ -2115,8 +2114,8 @@ static size_t ip6gre_get_size(const struct net_device *dev)
 
 static int ip6gre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct ip6_tnl *t = netdev_priv(dev);
-	struct __ip6_tnl_parm *p = &t->parms;
+	const struct ip6_tnl *t = netdev_priv(dev);
+	const struct __ip6_tnl_parm *p = &t->parms;
 	IP_TUNNEL_DECLARE_FLAGS(o_flags);
 
 	ip_tunnel_flags_copy(o_flags, p->o_flags);

gemini-3.1-pro-preview

null

null

							input: 4217
							output: 24
							thoughts: 891
						

**Analyzing a GRE Tunnel Flags Bug Fix**

Okay, so I'm looking at this patch that's touching `net/ipv4/ip_gre.c` and `net/ipv6/ip6_gre.c`. It's pretty straightforward: it's all about how GRE tunnel flags are handled. My initial thought is that this is good, flag handling is always a potential area for subtle concurrency bugs.

Specifically, it looks like `__gre_xmit` now gets the `flags` passed to it as an argument, which is the correct way to do this. Before, it was pulling the flags directly from `tunnel->parms.o_flags`. Makes sense; that keeps the transmission function itself cleaner and more focused. Then the other transmit functions (`ipgre_xmit`, `erspan_xmit`, `gre_tap_xmit`) copy the flags from `tunnel->parms.o_flags` to a local `flags` variable, potentially modify it, and *then* pass it to `__gre_xmit`. Right. Using a local copy is a key.

The more interesting part is in the `fill_info` functions (`ipgre_fill_info` and `erspan_fill_info`). It's fixing a bug where we were modifying `t->parms.o_flags` during a *read* operation – `fill_info` is for netlink, right? It used to set the `IP_TUNNEL_KEY_BIT` directly on the tunnel parameters during the `fill_info` call! That's a huge problem. That's a clear state corruption bug.

Now, it copies the flags into a local `o_flags` variable: `IP_TUNNEL_DECLARE_FLAGS(o_flags)` and then `ip_tunnel_flags_copy(o_flags, p->o_flags)`. Now it's safe to modify it without side-effects. After the copy, it conditionally sets `IP_TUNNEL_KEY_BIT` on *that* local copy, `o_flags`. That's smart. That protects against someone querying the tunnel info and changing the state underneath you. The same change also shows up in `ip6erspan_tunnel_xmit`. Good stuff.

So, the underlying issue is a concurrency or state corruption bug. We were modifying shared tunnel state (`t->parms.o_flags`) during both transmit and netlink dumps (which could happen concurrently), leading to data races. That can corrupt the tunnel state in subtle ways. It's not about uninitialized memory or info leaks, but it's about modifying shared state without proper locking.

Let me just double-check `ipgre_fill_info` again to be sure... `IP_TUNNEL_DECLARE_FLAGS` creates a bitmap, then we copy the flags, and only then do we modify the copy before converting to `__be16` and sending over netlink. I don't see any uninitialized memory issues in the code. It's a clean fix for a pretty nasty bug. Good catch.

{
  "Expression": "#define IP_TUNNEL_DECLARE_FLAGS"
}

{
  "Output": "include/net/ip_tunnels.h-51-\ninclude/net/ip_tunnels.h:52:#define IP_TUNNEL_DECLARE_FLAGS(...)\t\t\t\t\\\ninclude/net/ip_tunnels.h-53-\t__ipt_flag_op(DECLARE_BITMAP, __VA_ARGS__)\n"
}

gemini-3.1-pro-preview

null

null

							input: 5878
							output: 22
							thoughts: 12
						

Okay, here's my interpretation of that thought process, tailored for an expert audience, and written in the first person:

**Analyzing the Function Call**

Alright, the initial focus here is on the function call: `__ipt_flag_op`. Hmm, interesting. My brain immediately starts running through the potential implications. It's prefixed with a double underscore, so it's likely an internal or kernel-level function, which implies we're dealing with lower-level networking operations, possibly related to netfilter, iptables, or a similar firewall/packet manipulation framework. The name itself, `__ipt_flag_op`, suggests it's involved in *flag* operations, and probably at an *operator* level. This tells me we're likely manipulating or testing some kind of flag within the context of packet matching or rule application. I immediately need more context to understand precisely what flags and operators are in play. Is this within the iptables structure itself, or is this related to user-space iptables interaction? What data structures are probably being handled and where do they sit in the memory space? More questions. I need more information to dig deeper.

{
  "Expression": "#define __ipt_flag_op"
}

{
  "Output": "include/net/ip_tunnels.h-48-\ninclude/net/ip_tunnels.h:49:#define __ipt_flag_op(op, ...)\t\t\t\t\t\\\ninclude/net/ip_tunnels.h-50-\top(__VA_ARGS__, __IP_TUNNEL_FLAG_NUM)\n"
}

gemini-3.1-pro-preview

null

null

							input: 6241
							output: 23
							thoughts: 65
						

Okay, let me break this down.

**Understanding the Tunnel Flag Declaration and Copy Process**

Right, so I'm seeing this `IP_TUNNEL_DECLARE_FLAGS(o_flags)` macro. It's expanding to `DECLARE_BITMAP(o_flags, __IP_TUNNEL_FLAG_NUM)`. That tells me we're dealing with bit flags, packed into a bitmap. `DECLARE_BITMAP` is definitely going to resolve to an array of `unsigned long` values. That's standard practice, efficient for bit manipulation. We’re using longs, probably because we’re working with the architecture’s native word size to make the operations as fast as possible. This is a common and reasonable approach to managing a set of boolean options, or flags.

Then, there's `ip_tunnel_flags_copy`. Given the context, this *has* to be a function designed specifically to copy these bit flags from one bitmap (source) to another (destination). It’s probably implemented using bitwise operators like `&`, `|`, `~` (AND, OR, NOT) to selectively set, clear, and copy the individual bits within the `unsigned long` arrays that comprise the bitmaps. The function's job is straightforward: ensure the flags representing the tunnel's configuration are correctly transferred, probably when setting up or modifying a tunnel. No surprises here, just efficient bit-level manipulation.

{
  "Expression": "#define ip_tunnel_flags_copy"
}

{
  "Output": "include/net/ip_tunnels.h-55-#define ip_tunnel_flags_zero(...)\t__ipt_flag_op(bitmap_zero, __VA_ARGS__)\ninclude/net/ip_tunnels.h:56:#define ip_tunnel_flags_copy(...)\t__ipt_flag_op(bitmap_copy, __VA_ARGS__)\ninclude/net/ip_tunnels.h-57-#define ip_tunnel_flags_and(...)\t__ipt_flag_op(bitmap_and, __VA_ARGS__)\n"
}

gemini-3.1-pro-preview

null

null

							input: 6763
							output: 20
							thoughts: 69
						

**Concern Regarding Bitmap Copying and Potential Uninitialized Bits**

Okay, so I'm thinking about how `bitmap_copy` works here. It's supposed to copy an exact number of bits, which is straightforward enough. However, a potential issue is starting to niggle at me. If `__IP_TUNNEL_FLAG_NUM` isn't a clean multiple of `BITS_PER_LONG` – that is, if there's a remainder when you divide the number of flags by the bit width of an `unsigned long` – then `bitmap_copy` might be leaving the trailing bits of the last `unsigned long` in the destination uninitialized. We can't have that; it could lead to unexpected behavior later on. So, I need to verify that `bitmap_copy` handles this situation correctly. Let's dive in and take a close look at its implementation. I'm going to check the code.

{
  "Expression": "static inline void bitmap_copy"
}

{
  "Output": "include/linux/bitmap.h=273=void bitmap_copy_clear_tail(unsigned long *dst, const unsigned long *src, unsigned int nbits)\n--\ninclude/linux/bitmap.h-279-\ninclude/linux/bitmap.h:280:static inline void bitmap_copy_and_extend(unsigned long *to,\ninclude/linux/bitmap.h-281-\t\t\t\t\t  const unsigned long *from,\n"
}

gemini-3.1-pro-preview

null

null

							input: 7163
							output: 19
							thoughts: 13
						

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Analyzing the `bitmap_copy` Implementation**

Okay, first things first, I need to refresh my memory on the `bitmap_copy` macro or function. I'm going to quickly review its definition. What's the implementation like? Is it a straightforward bitwise operation, potentially optimized with compiler intrinsics, or something more complex that relies on memory management or hardware-specific instructions? I'll be looking for any potential gotchas—alignment issues, potential for off-by-one errors in loop boundaries, or any assumptions made about the underlying bitmap representation. Understanding these details will dictate whether it is actually what I'm looking for, performance wise. I need to make sure this `bitmap_copy` is doing what I believe it is.

no matches

{
  "Expression": "#define bitmap_copy"
}

{
  "error": "no matches"
}

gemini-3.1-pro-preview

null

null

							input: 7383
							output: 18
							thoughts: 19
						

Here's my thought process, summarized as you requested:

**Delving into Bitmap Manipulation**

Okay, time to get my hands dirty. I need to refresh my memory on the specifics of `bitmap_copy`. My first instinct is to navigate directly to the source. Let's see... `bitmap_copy`, right? That function is declared in `include/linux/bitmap.h`. I'll open that file and confirm the implementation details. I want to make sure I understand the expected behavior under various conditions. I need to be sure the function is optimized as I'd expect it to be, using the appropriate bitwise operations. This is where the core logic will reside. I want to check for edge cases, potential performance bottlenecks and how it handles different word sizes (32/64 bit). I'll also glance at how it handles the most common usage. I will want to see if this copy routine uses unrolled loops, which is often crucial for performance here, or if there's any clever trickery with SIMD instructions (though in the kernel, that's less common, admittedly).

{
  "Expression": "bitmap_copy\\("
}

{
  "Output": "\nFull output is too long, showing 500 out of 801 lines.\nUse more precise expression if possible.\n\narch/arm64/kernel/fpsimd.c=1023=void __init vec_init_vq_map(enum vec_type type)\n--\narch/arm64/kernel/fpsimd.c-1026-\tvec_probe_vqs(info, info-\u003evq_map);\narch/arm64/kernel/fpsimd.c:1027:\tbitmap_copy(info-\u003evq_partial_map, info-\u003evq_map, SVE_VQ_MAX);\narch/arm64/kernel/fpsimd.c-1028-}\n--\narch/arm64/kvm/arm.c=1663=static int __kvm_vcpu_set_target(struct kvm_vcpu *vcpu,\n--\narch/arm64/kvm/arm.c-1675-\narch/arm64/kvm/arm.c:1676:\tbitmap_copy(kvm-\u003earch.vcpu_features, \u0026features, KVM_VCPU_MAX_FEATURES);\narch/arm64/kvm/arm.c-1677-\n--\narch/arm64/kvm/hyp/nvhe/pkvm.c=339=static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struct kvm *host_kvm)\n--\narch/arm64/kvm/hyp/nvhe/pkvm.c-355-\narch/arm64/kvm/hyp/nvhe/pkvm.c:356:\t\tbitmap_copy(kvm-\u003earch.vcpu_features,\narch/arm64/kvm/hyp/nvhe/pkvm.c-357-\t\t\t    host_kvm-\u003earch.vcpu_features,\n--\narch/arm64/kvm/vgic/vgic-v5.c=370=void vgic_v5_fold_ppi_state(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/vgic/vgic-v5.c-402-\t */\narch/arm64/kvm/vgic/vgic-v5.c:403:\tbitmap_copy(cpu_if-\u003evgic_ppi_activer, activer, VGIC_V5_NR_PRIVATE_IRQS);\narch/arm64/kvm/vgic/vgic-v5.c-404-}\n--\narch/arm64/kvm/vgic/vgic-v5.c=406=void vgic_v5_flush_ppi_state(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/vgic/vgic-v5.c-437-\t */\narch/arm64/kvm/vgic/vgic-v5.c:438:\tbitmap_copy(host_data_ptr(vgic_v5_ppi_state)-\u003ependr, pendr,\narch/arm64/kvm/vgic/vgic-v5.c-439-\t\t    VGIC_V5_NR_PRIVATE_IRQS);\n--\narch/arm64/mm/context.c=91=static void set_reserved_asid_bits(void)\n--\narch/arm64/mm/context.c-93-\tif (pinned_asid_map)\narch/arm64/mm/context.c:94:\t\tbitmap_copy(asid_map, pinned_asid_map, NUM_USER_ASIDS);\narch/arm64/mm/context.c-95-\telse if (arm64_kernel_unmapped_at_el0())\n--\narch/powerpc/mm/book3s64/slice.c=390=static inline void slice_copy_mask(struct slice_mask *dst,\n--\narch/powerpc/mm/book3s64/slice.c-395-\t\treturn;\narch/powerpc/mm/book3s64/slice.c:396:\tbitmap_copy(dst-\u003ehigh_slices, src-\u003ehigh_slices, SLICE_NUM_HIGH);\narch/powerpc/mm/book3s64/slice.c-397-}\n--\narch/riscv/kernel/cpufeature.c=625=static void __init riscv_resolve_isa(unsigned long *source_isa,\n--\narch/riscv/kernel/cpufeature.c-640-\t\t}\narch/riscv/kernel/cpufeature.c:641:\t\tbitmap_copy(prev_resolved_isa, resolved_isa, RISCV_ISA_EXT_MAX);\narch/riscv/kernel/cpufeature.c-642-\t\tfor_each_set_bit(bit, source_isa, RISCV_ISA_EXT_MAX) {\n--\narch/riscv/kernel/cpufeature.c=831=static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)\n--\narch/riscv/kernel/cpufeature.c-914-\t\tif (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))\narch/riscv/kernel/cpufeature.c:915:\t\t\tbitmap_copy(riscv_isa, isainfo-\u003eisa, RISCV_ISA_EXT_MAX);\narch/riscv/kernel/cpufeature.c-916-\t\telse\n--\narch/riscv/kernel/cpufeature.c=957=static void __init riscv_fill_vendor_ext_list(int cpu)\n--\narch/riscv/kernel/cpufeature.c-965-\t\tif (!ext_list-\u003eis_initialized) {\narch/riscv/kernel/cpufeature.c:966:\t\t\tbitmap_copy(ext_list-\u003eall_harts_isa_bitmap.isa,\narch/riscv/kernel/cpufeature.c-967-\t\t\t\t    ext_list-\u003eper_hart_isa_bitmap[cpu].isa,\n--\narch/riscv/kernel/cpufeature.c=1019=static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)\n--\narch/riscv/kernel/cpufeature.c-1065-\t\tif (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))\narch/riscv/kernel/cpufeature.c:1066:\t\t\tbitmap_copy(riscv_isa, isainfo-\u003eisa, RISCV_ISA_EXT_MAX);\narch/riscv/kernel/cpufeature.c-1067-\t\telse\n--\narch/x86/events/intel/core.c=4496=intel_get_event_constraints(struct cpu_hw_events *cpuc, int idx,\n--\narch/x86/events/intel/core.c-4510-\t        WARN_ON_ONCE(!(c1-\u003eflags \u0026 PERF_X86_EVENT_DYNAMIC));\narch/x86/events/intel/core.c:4511:\t\tbitmap_copy(c1-\u003eidxmsk, c2-\u003eidxmsk, X86_PMC_IDX_MAX);\narch/x86/events/intel/core.c-4512-\t\tc1-\u003eweight = c2-\u003eweight;\n--\narch/x86/include/asm/mpspec.h=72=static inline void copy_phys_cpu_present_map(unsigned long *dst)\narch/x86/include/asm/mpspec.h-73-{\narch/x86/include/asm/mpspec.h:74:\tbitmap_copy(dst, phys_cpu_present_map, MAX_LOCAL_APIC);\narch/x86/include/asm/mpspec.h-75-}\n--\narch/x86/kvm/pmu.c=649=void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/pmu.c-655-\narch/x86/kvm/pmu.c:656:\tbitmap_copy(bitmap, pmu-\u003ereprogram_pmi, X86_PMC_IDX_MAX);\narch/x86/kvm/pmu.c-657-\n--\narch/x86/kvm/pmu.c=1119=static void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu,\n--\narch/x86/kvm/pmu.c-1132-\tif (!kvm_pmu_has_perf_global_ctrl(pmu))\narch/x86/kvm/pmu.c:1133:\t\tbitmap_copy(bitmap, event_pmcs, X86_PMC_IDX_MAX);\narch/x86/kvm/pmu.c-1134-\telse if (!bitmap_and(bitmap, event_pmcs,\n--\ndrivers/android/dbitmap.h=70=dbitmap_replace(struct dbitmap *dmap, unsigned long *new, unsigned int nbits)\ndrivers/android/dbitmap.h-71-{\ndrivers/android/dbitmap.h:72:\tbitmap_copy(new, dmap-\u003emap, min(dmap-\u003enbits, nbits));\ndrivers/android/dbitmap.h-73-\tkfree(dmap-\u003emap);\n--\ndrivers/crypto/ccp/ccp-dev-v5.c=608=static int ccp_find_and_assign_lsb_to_q(struct ccp_device *ccp,\n--\ndrivers/crypto/ccp/ccp-dev-v5.c-632-\t\tif (qlsb_wgt == lsb_cnt) {\ndrivers/crypto/ccp/ccp-dev-v5.c:633:\t\t\tbitmap_copy(qlsb, cmd_q-\u003elsbmask, MAX_LSB_CNT);\ndrivers/crypto/ccp/ccp-dev-v5.c-634-\n--\ndrivers/crypto/ccp/ccp-dev-v5.c=665=static int ccp_assign_lsbs(struct ccp_device *ccp)\n--\ndrivers/crypto/ccp/ccp-dev-v5.c-707-\t */\ndrivers/crypto/ccp/ccp-dev-v5.c:708:\tbitmap_copy(qlsb, lsb_pub, MAX_LSB_CNT);\ndrivers/crypto/ccp/ccp-dev-v5.c-709-\n--\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c=1058=static int eng_grp_update_masks(struct device *dev,\n--\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c-1101-\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c:1102:\t\tbitmap_copy(engs-\u003ebmap, tmp_bmap.bits, eng_grp-\u003eg-\u003eengs_num);\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c-1103-\t}\n--\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c-1119-\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c:1120:\t\tbitmap_copy(tmp_bmap.bits, mirrored_engs-\u003ebmap,\ndrivers/crypto/marvell/octeontx/otx_cptpf_ucode.c-1121-\t\t\t    eng_grp-\u003eg-\u003eengs_num);\n--\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c=855=static int eng_grp_update_masks(struct device *dev,\n--\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c-902-\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c:903:\t\tbitmap_copy(engs-\u003ebmap, tmp_bmap.bits, eng_grp-\u003eg-\u003eengs_num);\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c-904-\t}\n--\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c-920-\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c:921:\t\tbitmap_copy(tmp_bmap.bits, mirrored_engs-\u003ebmap,\ndrivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c-922-\t\t\t    eng_grp-\u003eg-\u003eengs_num);\n--\ndrivers/dma/idxd/device.c=379=static void idxd_wq_disable_cleanup(struct idxd_wq *wq)\n--\ndrivers/dma/idxd/device.c-394-\tif (wq-\u003eopcap_bmap)\ndrivers/dma/idxd/device.c:395:\t\tbitmap_copy(wq-\u003eopcap_bmap, idxd-\u003eopcap_bmap, IDXD_MAX_OPCAP_BITS);\ndrivers/dma/idxd/device.c-396-}\n--\ndrivers/dma/idxd/init.c=173=static int idxd_setup_wqs(struct idxd_device *idxd)\n--\ndrivers/dma/idxd/init.c-233-\t\t\t}\ndrivers/dma/idxd/init.c:234:\t\t\tbitmap_copy(wq-\u003eopcap_bmap, idxd-\u003eopcap_bmap, IDXD_MAX_OPCAP_BITS);\ndrivers/dma/idxd/init.c-235-\t\t}\n--\ndrivers/dma/idxd/init.c=821=static int idxd_device_config_save(struct idxd_device *idxd,\n--\ndrivers/dma/idxd/init.c-892-\ndrivers/dma/idxd/init.c:893:\tbitmap_copy(saved_wq_enable_map, idxd-\u003ewq_enable_map, idxd-\u003emax_wqs);\ndrivers/dma/idxd/init.c-894-\n--\ndrivers/dma/idxd/init.c=942=static void idxd_device_config_restore(struct idxd_device *idxd,\n--\ndrivers/dma/idxd/init.c-980-\ndrivers/dma/idxd/init.c:981:\tbitmap_copy(idxd-\u003ewq_enable_map, idxd_saved-\u003esaved_wq_enable_map,\ndrivers/dma/idxd/init.c-982-\t\t    idxd-\u003emax_wqs);\n--\ndrivers/dma/idxd/sysfs.c=1251=static ssize_t wq_op_config_store(struct device *dev, struct device_attribute *attr,\n--\ndrivers/dma/idxd/sysfs.c-1273-\ndrivers/dma/idxd/sysfs.c:1274:\tbitmap_copy(wq-\u003eopcap_bmap, opmask, IDXD_MAX_OPCAP_BITS);\ndrivers/dma/idxd/sysfs.c-1275-\n--\ndrivers/gpio/gpio-ljca.c=230=static int ljca_gpio_init_valid_mask(struct gpio_chip *chip,\n--\ndrivers/gpio/gpio-ljca.c-236-\tWARN_ON_ONCE(ngpios != ljca_gpio-\u003egpio_info-\u003enum);\ndrivers/gpio/gpio-ljca.c:237:\tbitmap_copy(valid_mask, ljca_gpio-\u003egpio_info-\u003evalid_pin_map, ngpios);\ndrivers/gpio/gpio-ljca.c-238-\n--\ndrivers/gpio/gpio-ltc4283.c=160=static int ltc4283_init_valid_mask(struct gpio_chip *gc, unsigned long *valid_mask,\n--\ndrivers/gpio/gpio-ltc4283.c-164-\ndrivers/gpio/gpio-ltc4283.c:165:\tbitmap_copy(valid_mask, mask, ngpios);\ndrivers/gpio/gpio-ltc4283.c-166-\treturn 0;\n--\ndrivers/gpio/gpio-pca953x.c=950=static bool pca953x_irq_pending(struct pca953x_chip *chip, unsigned long *pending)\n--\ndrivers/gpio/gpio-pca953x.c-988-\ndrivers/gpio/gpio-pca953x.c:989:\tbitmap_copy(old_stat, chip-\u003eirq_stat, gc-\u003engpio);\ndrivers/gpio/gpio-pca953x.c-990-\n--\ndrivers/gpio/gpio-pca953x.c-994-\ndrivers/gpio/gpio-pca953x.c:995:\tbitmap_copy(chip-\u003eirq_stat, new_stat, gc-\u003engpio);\ndrivers/gpio/gpio-pca953x.c-996-\n--\ndrivers/gpio/gpio-regmap.c=291=struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)\n--\ndrivers/gpio/gpio-regmap.c-363-\t\t}\ndrivers/gpio/gpio-regmap.c:364:\t\tbitmap_copy(gpio-\u003efixed_direction_mask,\ndrivers/gpio/gpio-regmap.c-365-\t\t\t    config-\u003efixed_direction_mask, chip-\u003engpio);\n--\ndrivers/gpio/gpio-regmap.c-374-\t\t}\ndrivers/gpio/gpio-regmap.c:375:\t\tbitmap_copy(gpio-\u003efixed_direction_output,\ndrivers/gpio/gpio-regmap.c-376-\t\t\t    config-\u003efixed_direction_output, chip-\u003engpio);\n--\ndrivers/gpio/gpio-xilinx.c=178=static int xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,\n--\ndrivers/gpio/gpio-xilinx.c-195-\ndrivers/gpio/gpio-xilinx.c:196:\tbitmap_copy(chip-\u003estate, state, 64);\ndrivers/gpio/gpio-xilinx.c-197-\n--\ndrivers/gpio/gpio-xilinx.c=477=static void xgpio_irqhandler(struct irq_desc *desc)\n--\ndrivers/gpio/gpio-xilinx.c-505-\ndrivers/gpio/gpio-xilinx.c:506:\tbitmap_copy(chip-\u003elast_irq_read, hw, 64);\ndrivers/gpio/gpio-xilinx.c-507-\tbitmap_or(hw, rising, falling, 64);\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c=325=svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-359-\tif (p-\u003exnack_enabled)\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:360:\t\tbitmap_copy(prange-\u003ebitmap_access, svms-\u003ebitmap_supported,\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-361-\t\t\t    MAX_GPU_INSTANCE);\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c=1047=svm_range_split_adjust(struct svm_range *new, struct svm_range *old,\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-1079-\tnew-\u003emapped_to_gpu = old-\u003emapped_to_gpu;\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:1080:\tbitmap_copy(new-\u003ebitmap_access, old-\u003ebitmap_access, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:1081:\tbitmap_copy(new-\u003ebitmap_aip, old-\u003ebitmap_aip, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-1082-\tatomic_set(\u0026new-\u003equeue_refcount, atomic_read(\u0026old-\u003equeue_refcount));\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c=1679=static int svm_range_validate_and_map(struct mm_struct *mm,\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-1701-\t} else if (ctx-\u003eprocess-\u003exnack_enabled) {\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:1702:\t\tbitmap_copy(ctx-\u003ebitmap, prange-\u003ebitmap_aip, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-1703-\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-1727-\t\t\t    prange-\u003eflags \u0026 KFD_IOCTL_SVM_FLAG_GPU_ALWAYS_MAPPED)\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:1728:\t\t\t\tbitmap_copy(ctx-\u003ebitmap, prange-\u003ebitmap_access, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-1729-\t\t}\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c=2091=static struct svm_range *svm_range_clone(struct svm_range *old)\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-2116-\tnew-\u003evram_pages = old-\u003evram_pages;\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:2117:\tbitmap_copy(new-\u003ebitmap_access, old-\u003ebitmap_access, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:2118:\tbitmap_copy(new-\u003ebitmap_aip, old-\u003ebitmap_aip, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-2119-\tatomic_set(\u0026new-\u003equeue_refcount, atomic_read(\u0026old-\u003equeue_refcount));\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c=3515=svm_range_best_prefetch_location(struct svm_range *prange)\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-3541-\tif (p-\u003exnack_enabled)\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:3542:\t\tbitmap_copy(bitmap, prange-\u003ebitmap_aip, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-3543-\telse\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c=3847=svm_range_get_attr(struct kfd_process *p, struct mm_struct *mm,\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-3927-\t\tif (p-\u003exnack_enabled)\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:3928:\t\t\tbitmap_copy(bitmap_access, svms-\u003ebitmap_supported,\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-3929-\t\t\t\t    MAX_GPU_INSTANCE);\n--\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-3934-\t}\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:3935:\tbitmap_copy(bitmap_access, svms-\u003ebitmap_supported, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c:3936:\tbitmap_copy(bitmap_aip, svms-\u003ebitmap_supported, MAX_GPU_INSTANCE);\ndrivers/gpu/drm/amd/amdkfd/kfd_svm.c-3937-\n--\ndrivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h=2085=static inline void smu_feature_bits_copy(struct smu_feature_bits *dst,\n--\ndrivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h-2088-{\ndrivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h:2089:\tbitmap_copy(dst-\u003ebits, src, nbits);\ndrivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h-2090-}\n--\ndrivers/gpu/drm/i915/display/intel_display_power.c=676=intel_display_power_put_async_work(struct work_struct *work)\n--\ndrivers/gpu/drm/i915/display/intel_display_power.c-705-\tif (!bitmap_empty(power_domains-\u003easync_put_domains[1].bits, POWER_DOMAIN_NUM)) {\ndrivers/gpu/drm/i915/display/intel_display_power.c:706:\t\tbitmap_copy(power_domains-\u003easync_put_domains[0].bits,\ndrivers/gpu/drm/i915/display/intel_display_power.c-707-\t\t\t    power_domains-\u003easync_put_domains[1].bits,\n--\ndrivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c=360=struct mdp5_smp *mdp5_smp_init(struct mdp5_kms *mdp5_kms, const struct mdp5_smp_block *cfg)\n--\ndrivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c-378-\t/* statically tied MMBs cannot be re-allocated: */\ndrivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c:379:\tbitmap_copy(state-\u003estate, cfg-\u003ereserved_state, smp-\u003eblk_cnt);\ndrivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c-380-\tmemcpy(smp-\u003ereserved, cfg-\u003ereserved, sizeof(smp-\u003ereserved));\n--\ndrivers/hwmon/peci/dimmtemp.c=213=static int check_populated_dimms(struct peci_dimmtemp *priv)\n--\ndrivers/hwmon/peci/dimmtemp.c-282-\ndrivers/hwmon/peci/dimmtemp.c:283:\tbitmap_copy(priv-\u003edimm_mask, dimm_mask, DIMM_NUMS_MAX);\ndrivers/hwmon/peci/dimmtemp.c-284-\n--\ndrivers/iio/adc/max1363.c=1453=static int max1363_alloc_scan_masks(struct iio_dev *indio_dev)\n--\ndrivers/iio/adc/max1363.c-1467-\tfor (i = 0; i \u003c st-\u003echip_info-\u003enum_modes; i++)\ndrivers/iio/adc/max1363.c:1468:\t\tbitmap_copy(masks + BITS_TO_LONGS(MAX1363_MAX_CHANNELS)*i,\ndrivers/iio/adc/max1363.c-1469-\t\t\t    max1363_mode_table[st-\u003echip_info-\u003emode_list[i]]\n--\ndrivers/iio/industrialio-buffer.c=510=static int iio_scan_mask_set(struct iio_dev *indio_dev,\n--\ndrivers/iio/industrialio-buffer.c-524-\t\treturn -ENOMEM;\ndrivers/iio/industrialio-buffer.c:525:\tbitmap_copy(trialmask, buffer-\u003escan_mask, masklength);\ndrivers/iio/industrialio-buffer.c-526-\tset_bit(bit, trialmask);\n--\ndrivers/iio/industrialio-buffer.c-536-\t}\ndrivers/iio/industrialio-buffer.c:537:\tbitmap_copy(buffer-\u003escan_mask, trialmask, masklength);\ndrivers/iio/industrialio-buffer.c-538-\n--\ndrivers/iio/proximity/d3323aa.c=222=static int d3323aa_write_settings(struct iio_dev *indio_dev,\n--\ndrivers/iio/proximity/d3323aa.c-273-\ndrivers/iio/proximity/d3323aa.c:274:\tbitmap_copy(written_regbitmap, regbitmap, D3323AA_REG_NR_BITS);\ndrivers/iio/proximity/d3323aa.c-275-\n--\ndrivers/input/evdev.c=884=static int evdev_handle_get_val(struct evdev_client *client,\n--\ndrivers/input/evdev.c-899-\ndrivers/input/evdev.c:900:\tbitmap_copy(mem, bits, maxbit);\ndrivers/input/evdev.c-901-\n--\ndrivers/input/keyboard/mt6779-keypad.c=48=static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)\n--\ndrivers/input/keyboard/mt6779-keypad.c-89-\ndrivers/input/keyboard/mt6779-keypad.c:90:\tbitmap_copy(keypad-\u003ekeymap_state, new_state, MTK_KPD_NUM_BITS);\ndrivers/input/keyboard/mt6779-keypad.c-91-\n--\ndrivers/input/rmi4/rmi_driver.c=372=static int rmi_driver_set_irq_bits(struct rmi_device *rmi_dev,\n--\ndrivers/input/rmi4/rmi_driver.c-391-\ndrivers/input/rmi4/rmi_driver.c:392:\tbitmap_copy(data-\u003ecurrent_irq_mask, data-\u003enew_irq_mask, data-\u003eirq_count);\ndrivers/input/rmi4/rmi_driver.c-393-\tbitmap_or(data-\u003efn_irq_bits, data-\u003efn_irq_bits, mask, data-\u003eirq_count);\n--\ndrivers/input/rmi4/rmi_driver.c=400=static int rmi_driver_clear_irq_bits(struct rmi_device *rmi_dev,\n--\ndrivers/input/rmi4/rmi_driver.c-421-\ndrivers/input/rmi4/rmi_driver.c:422:\tbitmap_copy(data-\u003ecurrent_irq_mask, data-\u003enew_irq_mask, data-\u003eirq_count);\ndrivers/input/rmi4/rmi_driver.c-423-\n--\ndrivers/irqchip/irq-mips-gic.c=843=static int gic_register_ipi_domain(struct device_node *node)\n--\ndrivers/irqchip/irq-mips-gic.c-870-\ndrivers/irqchip/irq-mips-gic.c:871:\tbitmap_copy(ipi_available, ipi_resrv, GIC_MAX_INTRS);\ndrivers/irqchip/irq-mips-gic.c-872-\n--\ndrivers/md/dm-integrity.c=585=static bool block_bitmap_op(struct dm_integrity_c *ic, struct page_list *bitmap,\n--\ndrivers/md/dm-integrity.c-690-\ndrivers/md/dm-integrity.c:691:static void block_bitmap_copy(struct dm_integrity_c *ic, struct page_list *dst, struct page_list *src)\ndrivers/md/dm-integrity.c-692-{\n--\ndrivers/md/dm-integrity.c=3783=static void dm_integrity_resume(struct dm_target *ti)\n--\ndrivers/md/dm-integrity.c-3830-\t\t\t    !ic-\u003ereset_recalculate_flag) {\ndrivers/md/dm-integrity.c:3831:\t\t\t\tblock_bitmap_copy(ic, ic-\u003erecalc_bitmap, ic-\u003ejournal);\ndrivers/md/dm-integrity.c:3832:\t\t\t\tblock_bitmap_copy(ic, ic-\u003emay_write_bitmap, ic-\u003ejournal);\ndrivers/md/dm-integrity.c-3833-\t\t\t\tif (!block_bitmap_op(ic, ic-\u003ejournal, 0, ic-\u003eprovided_data_sectors,\n--\ndrivers/net/ethernet/amd/xgbe/xgbe.h-251-#define XGBE_LM_COPY(_dst, _dname, _src, _sname)\t\\\ndrivers/net/ethernet/amd/xgbe/xgbe.h:252:\tbitmap_copy((_dst)-\u003elink_modes._dname,\t\t\\\ndrivers/net/ethernet/amd/xgbe/xgbe.h-253-\t\t    (_src)-\u003elink_modes._sname,\t\t\\\n--\ndrivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c=3425=static ssize_t blocked_fl_write(struct file *filp, const char __user *ubuf,\n--\ndrivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c-3441-\ndrivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c:3442:\tbitmap_copy(adap-\u003esge.blocked_fl, t, adap-\u003esge.egr_sz);\ndrivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c-3443-\tbitmap_free(t);\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c=1732=static int hclge_vport_setup(struct hclge_vport *vport, u16 num_tqps)\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c-1739-\tnic-\u003eae_algo = \u0026ae_algo;\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c:1740:\tbitmap_copy(nic-\u003enuma_node_mask.bits, hdev-\u003enuma_node_mask.bits,\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c-1741-\t\t    MAX_NUMNODES);\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c=2414=static int hclge_init_roce_base_info(struct hclge_vport *vport)\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c-2432-\troce-\u003eae_algo = nic-\u003eae_algo;\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c:2433:\tbitmap_copy(roce-\u003enuma_node_mask.bits, nic-\u003enuma_node_mask.bits,\ndrivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c-2434-\t\t    MAX_NUMNODES);\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c=447=static int hclgevf_set_handle_info(struct hclgevf_dev *hdev)\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c-453-\tnic-\u003epdev = hdev-\u003epdev;\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c:454:\tbitmap_copy(nic-\u003enuma_node_mask.bits, hdev-\u003enuma_node_mask.bits,\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c-455-\t\t    MAX_NUMNODES);\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c=2144=static int hclgevf_init_roce_base_info(struct hclgevf_dev *hdev)\n--\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c-2162-\troce-\u003eae_algo = nic-\u003eae_algo;\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c:2163:\tbitmap_copy(roce-\u003enuma_node_mask.bits, nic-\u003enuma_node_mask.bits,\ndrivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c-2164-\t\t    MAX_NUMNODES);\n--\ndrivers/net/ethernet/huawei/hinic3/hinic3_ethtool.c=385=hinic3_get_link_ksettings(struct net_device *netdev,\n--\ndrivers/net/ethernet/huawei/hinic3/hinic3_ethtool.c-398-\ndrivers/net/ethernet/huawei/hinic3/hinic3_ethtool.c:399:\tbitmap_copy(link_settings-\u003elink_modes.supported, settings.supported,\ndrivers/net/ethernet/huawei/hinic3/hinic3_ethtool.c-400-\t\t    __ETHTOOL_LINK_MODE_MASK_NBITS);\ndrivers/net/ethernet/huawei/hinic3/hinic3_ethtool.c:401:\tbitmap_copy(link_settings-\u003elink_modes.advertising, settings.advertising,\ndrivers/net/ethernet/huawei/hinic3/hinic3_ethtool.c-402-\t\t    __ETHTOOL_LINK_MODE_MASK_NBITS);\n--\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c=5238=static int i40e_set_priv_flags(struct net_device *dev, u32 flags)\n--\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c-5250-\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c:5251:\tbitmap_copy(orig_flags, pf-\u003eflags, I40E_PF_FLAGS_NBITS);\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c:5252:\tbitmap_copy(new_flags, pf-\u003eflags, I40E_PF_FLAGS_NBITS);\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c-5253-\n--\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c-5460-\t */\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c:5461:\tbitmap_copy(pf-\u003eflags, new_flags, I40E_PF_FLAGS_NBITS);\ndrivers/net/ethernet/intel/i40e/i40e_ethtool.c-5462-\n--\ndrivers/net/ethernet/intel/ice/ice_ethtool.c=1739=static int ice_set_priv_flags(struct net_device *netdev, u32 flags)\n--\ndrivers/net/ethernet/intel/ice/ice_ethtool.c-1755-\ndrivers/net/ethernet/intel/ice/ice_ethtool.c:1756:\tbitmap_copy(orig_flags, pf-\u003eflags, ICE_PF_FLAGS_NBITS);\ndrivers/net/ethernet/intel/ice/ice_ethtool.c-1757-\tfor (i = 0; i \u003c ICE_PRIV_FLAG_ARRAY_SIZE; i++) {\n--\ndrivers/net/ethernet/intel/ice/ice_sched.c=2617=ice_save_agg_tc_bitmap(struct ice_port_info *pi, u32 agg_id,\n--\ndrivers/net/ethernet/intel/ice/ice_sched.c-2624-\t\treturn -EINVAL;\ndrivers/net/ethernet/intel/ice/ice_sched.c:2625:\tbitmap_copy(agg_info-\u003ereplay_tc_bitmap, tc_bitmap,\ndrivers/net/ethernet/intel/ice/ice_sched.c-2626-\t\t    ICE_MAX_TRAFFIC_CLASS);\n--\ndrivers/net/ethernet/intel/ice/ice_sched.c=2861=ice_save_agg_vsi_tc_bitmap(struct ice_port_info *pi, u32 agg_id, u16 vsi_handle,\n--\ndrivers/net/ethernet/intel/ice/ice_sched.c-2873-\t\treturn -EINVAL;\ndrivers/net/ethernet/intel/ice/ice_sched.c:2874:\tbitmap_copy(agg_vsi_info-\u003ereplay_tc_bitmap, tc_bitmap,\ndrivers/net/ethernet/intel/ice/ice_sched.c-2875-\t\t    ICE_MAX_TRAFFIC_CLASS);\n--\ndrivers/net/ethernet/intel/ice/ice_switch.c=2281=static void ice_get_recp_to_prof_map(struct ice_hw *hw)\n--\ndrivers/net/ethernet/intel/ice/ice_switch.c-2294-\t\tbitmap_from_arr64(r_bitmap, \u0026recp_assoc, ICE_MAX_NUM_RECIPES);\ndrivers/net/ethernet/intel/ice/ice_switch.c:2295:\t\tbitmap_copy(profile_to_recipe[i], r_bitmap,\ndrivers/net/ethernet/intel/ice/ice_switch.c-2296-\t\t\t    ICE_MAX_NUM_RECIPES);\n--\ndrivers/net/ethernet/intel/ice/ice_switch.c=2315=ice_get_recp_frm_fw(struct ice_hw *hw, struct ice_sw_recipe *recps, u8 rid,\n--\ndrivers/net/ethernet/intel/ice/ice_switch.c-2432-\t/* Copy result indexes */\ndrivers/net/ethernet/intel/ice/ice_switch.c:2433:\tbitmap_copy(recps[rid].res_idxs, result_bm, ICE_MAX_FV_WORDS);\ndrivers/net/ethernet/intel/ice/ice_switch.c-2434-\tif (is_add)\n--\ndrivers/net/ethernet/intel/ice/ice_switch.c=5309=ice_add_adv_recipe(struct ice_hw *hw, struct ice_adv_lkup_elem *lkups,\n--\ndrivers/net/ethernet/intel/ice/ice_switch.c-5437-\t\t/* Update profile to recipe bitmap array */\ndrivers/net/ethernet/intel/ice/ice_switch.c:5438:\t\tbitmap_copy(profile_to_recipe[fvit-\u003eprofile_id], r_bitmap,\ndrivers/net/ethernet/intel/ice/ice_switch.c-5439-\t\t\t    ICE_MAX_NUM_RECIPES);\n--\ndrivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c=255=static int mlxsw_afk_picker(struct mlxsw_afk *mlxsw_afk,\n--\ndrivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c-301-\ndrivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c:302:\t\tbitmap_copy(picker[block_index].chosen_element,\ndrivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c-303-\t\t\t    picker[block_index].element, MLXSW_AFK_ELEMENT_MAX);\n--\ndrivers/net/ethernet/microchip/sparx5/sparx5_vlan.c=161=void sparx5_update_fwd(struct sparx5 *sparx5)\n--\ndrivers/net/ethernet/microchip/sparx5/sparx5_vlan.c-173-\t\t\t/* Allow to send to all bridged but self */\ndrivers/net/ethernet/microchip/sparx5/sparx5_vlan.c:174:\t\t\tbitmap_copy(workmask, sparx5-\u003ebridge_fwd_mask, SPX5_PORTS);\ndrivers/net/ethernet/microchip/sparx5/sparx5_vlan.c-175-\t\t\tclear_bit(port, workmask);\n--\ndrivers/net/ipvlan/ipvlan_main.c=318=static void ipvlan_set_multicast_mac_filter(struct net_device *dev)\n--\ndrivers/net/ipvlan/ipvlan_main.c-337-\ndrivers/net/ipvlan/ipvlan_main.c:338:\t\tbitmap_copy(ipvlan-\u003emac_filters, mc_filters,\ndrivers/net/ipvlan/ipvlan_main.c-339-\t\t\t    IPVLAN_MAC_FILTER_SIZE);\n--\ndrivers/net/macvlan.c=810=static void macvlan_compute_filter(unsigned long *mc_filter,\n--\ndrivers/net/macvlan.c-829-\ndrivers/net/macvlan.c:830:\t\tbitmap_copy(mc_filter, filter, MACVLAN_MC_FILTER_SZ);\ndrivers/net/macvlan.c-831-\t}\n--\ndrivers/net/wireless/ath/ath11k/wmi.c=526=static int ath11k_pull_service_ready_tlv(struct ath11k_base *ab,\n--\ndrivers/net/wireless/ath/ath11k/wmi.c-562- */\ndrivers/net/wireless/ath/ath11k/wmi.c:563:static void ath11k_wmi_service_bitmap_copy(struct ath11k_pdev_wmi *wmi,\ndrivers/net/wireless/ath/ath11k/wmi.c-564-\t\t\t\t\t   const u32 *wmi_svc_bm)\n--\ndrivers/net/wireless/ath/ath11k/wmi.c=576=static int ath11k_wmi_tlv_svc_rdy_parse(struct ath11k_base *ab, u16 tag, u16 len,\n--\ndrivers/net/wireless/ath/ath11k/wmi.c-597-\ndrivers/net/wireless/ath/ath11k/wmi.c:598:\t\t\tath11k_wmi_service_bitmap_copy(wmi_handle, ptr);\ndrivers/net/wireless/ath/ath11k/wmi.c-599-\n--\ndrivers/net/wireless/ath/ath12k/wmi.c=646=static int ath12k_pull_service_ready_tlv(struct ath12k_base *ab,\n--\ndrivers/net/wireless/ath/ath12k/wmi.c-682- */\ndrivers/net/wireless/ath/ath12k/wmi.c:683:static void ath12k_wmi_service_bitmap_copy(struct ath12k_wmi_pdev *wmi,\ndrivers/net/wireless/ath/ath12k/wmi.c-684-\t\t\t\t\t   const u32 *wmi_svc_bm)\n--\ndrivers/net/wireless/ath/ath12k/wmi.c=696=static int ath12k_wmi_svc_rdy_parse(struct ath12k_base *ab, u16 tag, u16 len,\n--\ndrivers/net/wireless/ath/ath12k/wmi.c-717-\ndrivers/net/wireless/ath/ath12k/wmi.c:718:\t\t\tath12k_wmi_service_bitmap_copy(wmi_handle, ptr);\ndrivers/net/wireless/ath/ath12k/wmi.c-719-\n--\ndrivers/net/wireless/realtek/rtw89/chan.c=593=enum rtw89_entity_mode rtw89_entity_recalc(struct rtw89_dev *rtwdev)\n--\ndrivers/net/wireless/realtek/rtw89/chan.c-604-\ndrivers/net/wireless/realtek/rtw89/chan.c:605:\tbitmap_copy(recalc_map, hal-\u003eentity_map, NUM_OF_RTW89_CHANCTX);\ndrivers/net/wireless/realtek/rtw89/chan.c-606-\n--\ndrivers/platform/x86/dell/alienware-wmi-wmax.c=1119=static int awcc_hwmon_fans_init(struct wmi_device *wdev)\n--\ndrivers/platform/x86/dell/alienware-wmi-wmax.c-1172-\t\tbitmap_gather(gather, fan_temps, priv-\u003etemp_sensors, AWCC_ID_BITMAP_SIZE);\ndrivers/platform/x86/dell/alienware-wmi-wmax.c:1173:\t\tbitmap_copy(\u0026fan_data-\u003eauto_channels_temp, gather, BITS_PER_LONG);\ndrivers/platform/x86/dell/alienware-wmi-wmax.c-1174-\t\tpriv-\u003efan_data[i] = fan_data;\n--\ndrivers/pnp/isapnp/core.c=410=static void __init isapnp_parse_irq_resource(struct pnp_dev *dev,\n--\ndrivers/pnp/isapnp/core.c-422-\tbitmap_zero(map.bits, PNP_IRQ_NR);\ndrivers/pnp/isapnp/core.c:423:\tbitmap_copy(map.bits, \u0026bits, 16);\ndrivers/pnp/isapnp/core.c-424-\n--\ndrivers/pnp/pnpbios/rsparser.c=262=static __init void pnpbios_parse_irq_option(struct pnp_dev *dev,\n--\ndrivers/pnp/pnpbios/rsparser.c-272-\tbitmap_zero(map.bits, PNP_IRQ_NR);\ndrivers/pnp/pnpbios/rsparser.c:273:\tbitmap_copy(map.bits, \u0026bits, 16);\ndrivers/pnp/pnpbios/rsparser.c-274-\n--\ndrivers/s390/crypto/vfio_ap_ops.c=671=static bool vfio_ap_mdev_filter_cdoms(struct ap_matrix_mdev *matrix_mdev)\n--\ndrivers/s390/crypto/vfio_ap_ops.c-674-\n\n"
}

gemini-3.1-pro-preview

null

null

							input: 20738
							output: 21
							thoughts: 29
						

Here's my take on the thought process:

**Diving into the Code: Understanding `bitmap_copy`**

Okay, so I see `bitmap_copy` and immediately register that it's likely a macro or inline function. Given the nature of this kernel code, that's almost a certainty. Now, I need to understand what it *does*. Time to go straight to the source. The natural place to start looking is `include/linux/bitmap.h`. That's where I'd expect to find the definition, along with any relevant documentation and, of course, the actual implementation that I'll need to analyze. Let's see what we've got in there.

no matches

{
  "Expression": "static inline void bitmap_copy\\("
}

{
  "error": "no matches"
}

gemini-3.1-pro-preview

null

null

							input: 20949
							output: 30
							thoughts: 110
						

**Realizing the Obvious**

Hold on a second... didn't I just see something about `bitmap_copy` in the output from the previous search? Ah, yes, there it is in `include/linux/bitmap.h`: specifically the definition of `bitmap_copy_and_extend`. Okay, I was too hasty. Let's not reinvent the wheel here. Let's go back and grep specifically for that function name, `bitmap_copy`, within that same header file, `include/linux/bitmap.h`. I need to make sure I'm not overlooking anything related to that function. It's probably already there and I just need to remind myself where it is.

{
  "Expression": "bitmap_copy",
  "PathPrefix": "include/linux/bitmap.h"
}

{
  "Output": "include/linux/bitmap.h=17=struct device;\n--\ninclude/linux/bitmap.h-44- *  bitmap_fill(dst, nbits)                     *dst = ~0UL\ninclude/linux/bitmap.h:45: *  bitmap_copy(dst, src, nbits)                *dst = *src\ninclude/linux/bitmap.h-46- *  bitmap_and(dst, src1, src2, nbits)          *dst = *src1 \u0026 *src2\n--\ninclude/linux/bitmap.h=258=static __always_inline\ninclude/linux/bitmap.h:259:void bitmap_copy(unsigned long *dst, const unsigned long *src, unsigned int nbits)\ninclude/linux/bitmap.h-260-{\n--\ninclude/linux/bitmap.h=272=static __always_inline\ninclude/linux/bitmap.h:273:void bitmap_copy_clear_tail(unsigned long *dst, const unsigned long *src, unsigned int nbits)\ninclude/linux/bitmap.h-274-{\ninclude/linux/bitmap.h:275:\tbitmap_copy(dst, src, nbits);\ninclude/linux/bitmap.h-276-\tif (nbits % BITS_PER_LONG)\n--\ninclude/linux/bitmap.h-279-\ninclude/linux/bitmap.h:280:static inline void bitmap_copy_and_extend(unsigned long *to,\ninclude/linux/bitmap.h-281-\t\t\t\t\t  const unsigned long *from,\n--\ninclude/linux/bitmap.h-295- * In both cases conversion is not needed when copying data from/to arrays of\ninclude/linux/bitmap.h:296: * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead\ninclude/linux/bitmap.h-297- * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit\ninclude/linux/bitmap.h:298: * architectures are not using bitmap_copy_clear_tail().\ninclude/linux/bitmap.h-299- */\n--\ninclude/linux/bitmap.h=303=void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,\n--\ninclude/linux/bitmap.h-306-#define bitmap_from_arr32(bitmap, buf, nbits)\t\t\t\\\ninclude/linux/bitmap.h:307:\tbitmap_copy_clear_tail((unsigned long *) (bitmap),\t\\\ninclude/linux/bitmap.h-308-\t\t\t(const unsigned long *) (buf), (nbits))\ninclude/linux/bitmap.h-309-#define bitmap_to_arr32(buf, bitmap, nbits)\t\t\t\\\ninclude/linux/bitmap.h:310:\tbitmap_copy_clear_tail((unsigned long *) (buf),\t\t\\\ninclude/linux/bitmap.h-311-\t\t\t(const unsigned long *) (bitmap), (nbits))\n--\ninclude/linux/bitmap.h=320=void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits);\n--\ninclude/linux/bitmap.h-322-#define bitmap_from_arr64(bitmap, buf, nbits)\t\t\t\\\ninclude/linux/bitmap.h:323:\tbitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits))\ninclude/linux/bitmap.h-324-#define bitmap_to_arr64(buf, bitmap, nbits)\t\t\t\\\ninclude/linux/bitmap.h:325:\tbitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits))\ninclude/linux/bitmap.h-326-#endif\n"
}

gemini-3.1-pro-preview

null

null

							input: 22173
							output: 35
							thoughts: 11
						

Okay, let's dive into this `bitmap_copy` implementation. I need to understand this thoroughly, especially given my background. I need to see exactly how this is implemented. I'm going to look at the code, consider the constraints, and the expected performance. I want to identify potential bottlenecks, memory access patterns, and any clever optimizations used. I'll need to assess its efficiency and make sure it aligns with best practices for my area of expertise. I'll be looking for possible edge cases or scenarios that might cause issues. I'll start by making sure it's correct and then move on to optimization.

{
  "File": "include/linux/bitmap.h",
  "FirstLine": 258,
  "LineCount": 20
}

{
  "Contents": " 258:\tstatic __always_inline\n 259:\tvoid bitmap_copy(unsigned long *dst, const unsigned long *src, unsigned int nbits)\n 260:\t{\n 261:\t\tunsigned int len = bitmap_size(nbits);\n 262:\t\n 263:\t\tif (small_const_nbits(nbits))\n 264:\t\t\t*dst = *src;\n 265:\t\telse\n 266:\t\t\tmemcpy(dst, src, len);\n 267:\t}\n 268:\t\n 269:\t/*\n 270:\t * Copy bitmap and clear tail bits in last word.\n 271:\t */\n 272:\tstatic __always_inline\n 273:\tvoid bitmap_copy_clear_tail(unsigned long *dst, const unsigned long *src, unsigned int nbits)\n 274:\t{\n 275:\t\tbitmap_copy(dst, src, nbits);\n 276:\t\tif (nbits % BITS_PER_LONG)\n 277:\t\t\tdst[nbits / BITS_PER_LONG] \u0026= BITMAP_LAST_WORD_MASK(nbits);\n"
}

gemini-3.1-pro-preview

null

null

							input: 22660
							output: 26
							thoughts: 195
						

**Analyzing the Data Copying Logic**

Okay, let me break this down. My initial understanding is that `bitmap_size` is calculated based on the number of bits (`nbits`) and is then used to determine how many `unsigned long` elements are in the bitmap, taking into account their size. The `bitmap_copy` function, therefore, works at the granularity of those full `unsigned long`s.

This is immediately relevant because I see `IP_TUNNEL_DECLARE_FLAGS` is declaring an array of `unsigned long`. If the macro just declares the array, the copy operation uses a size large enough to copy this entire array using `bitmap_copy`.

Now the interesting point: What if the declaration with `IP_TUNNEL_DECLARE_FLAGS(o_flags)` is *not* initializing the array? The copy is from `p->o_flags` to `o_flags`, and if `p->o_flags` is *also* an array of `unsigned long`, and since the `bitmap_copy` is configured to copy the entire array in a block using `BITS_TO_LONGS(nbits) * sizeof(unsigned long)`, the entire destination array will be populated in the copy.

Thus, the copy operation within `ip_tunnel_flags_copy` ensures that `o_flags` will be *fully* initialized as a side effect of the bitwise copy. Following that, we have `gre_tnl_flags_to_gre_flags(o_flags)`. So this explains how the flags are then converted.

{
  "Expression": "gre_tnl_flags_to_gre_flags"
}

{
  "Output": "drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_gre.c=27=static int mlx5e_gen_ip_tunnel_header_gretap(char buf[],\n--\ndrivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_gre.c-49-\thdr_len\t= mlx5e_tc_tun_calc_hlen_gretap(e);\ndrivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_gre.c:50:\tgreh-\u003eflags = gre_tnl_flags_to_gre_flags(tun_key-\u003etun_flags);\ndrivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_gre.c-51-\tif (test_bit(IP_TUNNEL_KEY_BIT, tun_key-\u003etun_flags)) {\n--\ninclude/net/gre.h=63=static inline void gre_flags_to_tnl_flags(unsigned long *dst, __be16 flags)\n--\ninclude/net/gre.h-77-\ninclude/net/gre.h:78:static inline __be16 gre_tnl_flags_to_gre_flags(const unsigned long *tflags)\ninclude/net/gre.h-79-{\n--\ninclude/net/gre.h=100=static inline void gre_build_header(struct sk_buff *skb, int hdr_len,\n--\ninclude/net/gre.h-111-\tgreh = (struct gre_base_hdr *)skb-\u003edata;\ninclude/net/gre.h:112:\tgreh-\u003eflags = gre_tnl_flags_to_gre_flags(flags);\ninclude/net/gre.h-113-\tgreh-\u003eprotocol = proto;\n--\nnet/ipv4/ip_gre.c=821=static int ipgre_tunnel_ctl(struct net_device *dev,\n--\nnet/ipv4/ip_gre.c-858-\nnet/ipv4/ip_gre.c:859:\ti_flags = gre_tnl_flags_to_gre_flags(p-\u003ei_flags);\nnet/ipv4/ip_gre.c-860-\tip_tunnel_flags_from_be16(p-\u003ei_flags, i_flags);\nnet/ipv4/ip_gre.c:861:\to_flags = gre_tnl_flags_to_gre_flags(p-\u003eo_flags);\nnet/ipv4/ip_gre.c-862-\tip_tunnel_flags_from_be16(p-\u003eo_flags, o_flags);\n--\nnet/ipv4/ip_gre.c=894=static int ipgre_header(struct sk_buff *skb, struct net_device *dev,\n--\nnet/ipv4/ip_gre.c-910-\tgreh = (struct gre_base_hdr *)(iph+1);\nnet/ipv4/ip_gre.c:911:\tgreh-\u003eflags = gre_tnl_flags_to_gre_flags(t-\u003eparms.o_flags);\nnet/ipv4/ip_gre.c-912-\tgreh-\u003eprotocol = htons(type);\n--\nnet/ipv4/ip_gre.c=1565=static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)\n--\nnet/ipv4/ip_gre.c-1577-\t    nla_put_be16(skb, IFLA_GRE_IFLAGS,\nnet/ipv4/ip_gre.c:1578:\t\t\t gre_tnl_flags_to_gre_flags(p-\u003ei_flags)) ||\nnet/ipv4/ip_gre.c-1579-\t    nla_put_be16(skb, IFLA_GRE_OFLAGS,\nnet/ipv4/ip_gre.c:1580:\t\t\t gre_tnl_flags_to_gre_flags(o_flags)) ||\nnet/ipv4/ip_gre.c-1581-\t    nla_put_be32(skb, IFLA_GRE_IKEY, p-\u003ei_key) ||\n--\nnet/ipv6/ip6_gre.c=1235=static void ip6gre_tnl_parm_to_user(struct ip6_tnl_parm2 *u,\n--\nnet/ipv6/ip6_gre.c-1247-\tu-\u003eo_key = p-\u003eo_key;\nnet/ipv6/ip6_gre.c:1248:\tu-\u003ei_flags = gre_tnl_flags_to_gre_flags(p-\u003ei_flags);\nnet/ipv6/ip6_gre.c:1249:\tu-\u003eo_flags = gre_tnl_flags_to_gre_flags(p-\u003eo_flags);\nnet/ipv6/ip6_gre.c-1250-\tmemcpy(u-\u003ename, p-\u003ename, sizeof(u-\u003ename));\n--\nnet/ipv6/ip6_gre.c=2115=static int ip6gre_fill_info(struct sk_buff *skb, const struct net_device *dev)\n--\nnet/ipv6/ip6_gre.c-2142-\t    nla_put_be16(skb, IFLA_GRE_IFLAGS,\nnet/ipv6/ip6_gre.c:2143:\t\t\t gre_tnl_flags_to_gre_flags(p-\u003ei_flags)) ||\nnet/ipv6/ip6_gre.c-2144-\t    nla_put_be16(skb, IFLA_GRE_OFLAGS,\nnet/ipv6/ip6_gre.c:2145:\t\t\t gre_tnl_flags_to_gre_flags(o_flags)) ||\nnet/ipv6/ip6_gre.c-2146-\t    nla_put_be32(skb, IFLA_GRE_IKEY, p-\u003ei_key) ||\n"
}

gemini-3.1-pro-preview

null

null

							input: 24732
							output: 210
							thoughts: 940
						

**Analysis of the GRE Tunnel Flag Handling and Concurrency Fix**

Okay, so looking at this code, my initial assessment regarding `gre_tnl_flags_to_gre_flags` is confirmed: it's a simple bitmap conversion to `__be16`. The function checks specific bits, so there's no way for it to cause an uninitialized memory read or information leak. This confirms that KMSAN isn't the right tool here. The core problem is a concurrency issue or a logic error related to the tunnel parameters, specifically the `o_flags` field in `tunnel->parms`.

The crux of the issue is the modification of `t->parms.o_flags` either during transmission (`erspan_xmit`, `ipgre_xmit`) or during netlink dumps (`ipgre_fill_info`). This is inherently flawed because `t->parms` holds the *configured* state of the tunnel. If we're modifying it directly during packet processing or dump operations, we're introducing a data race. Subsequent packets or dumps might read this modified (and potentially inconsistent) state, which, while leading to incorrect behavior, does not introduce an uninitialized memory read. The problem is a corrupted tunnel state.

Now, let's look at the `__gre_xmit` changes. Ah, the old version copied `tunnel->parms.o_flags` to `flags` and passed that to `gre_build_header`. But `ipgre_xmit` and `erspan_xmit` were modifying the original `tunnel->parms.o_flags` before calling `__gre_xmit`. The fix now copies `tunnel->parms.o_flags` to a local `flags` variable *before* modification, and passes *that* to `__gre_xmit`. This is a pretty solid fix. It prevents modification of the shared `tunnel->parms.o_flags`.

Let's quickly confirm that `flags` is initialized in `ipgre_xmit`: `IP_TUNNEL_DECLARE_FLAGS(flags)` declares the array and `ip_tunnel_flags_copy(flags, tunnel->parms.o_flags)` does the copying. And we know that `bitmap_copy` does the right thing, copying the full array. So, the local `flags` variable *is* fully initialized. Same goes for `ipgre_fill_info` - it declares and initializes the local `o_flags` in the same way.

Therefore, this patch doesn't introduce any uninitialized memory issues. We are talking about a concurrency/logic bug, not an uninitialized read. The correct approach here is to use KASAN (or standard testing) to catch race conditions and memory corruption issues. KMSAN, which is for detecting uninitialized memory reads, is not needed. This is a fix for data races and logical errors, not uninitialized memory issues.

{
  "KMSANReasoning": "The patch fixes a concurrency and logic bug where shared tunnel parameters (`tunnel-\u003eparms.o_flags`) were being incorrectly modified during packet transmission (`erspan_xmit`, `ip6erspan_tunnel_xmit`) and netlink dumps (`ipgre_fill_info`, `erspan_fill_info`). This could lead to data races and corrupted tunnel state. The fix introduces local copies of the flags (`IP_TUNNEL_DECLARE_FLAGS`) which are fully initialized via `ip_tunnel_flags_copy()` (which uses `bitmap_copy()` to copy the entire `unsigned long` array). There is no introduction of uninitialized memory, nor any risk of info-leaks to user space. Standard KASAN/KCSAN and logic testing are sufficient to catch data races and memory corruption. KMSAN is specifically for uninitialized memory and is not applicable here.",
  "NeedsKMSAN": false
}

{
  "KMSANReasoning": "The patch fixes a concurrency and logic bug where shared tunnel parameters (`tunnel-\u003eparms.o_flags`) were being incorrectly modified during packet transmission (`erspan_xmit`, `ip6erspan_tunnel_xmit`) and netlink dumps (`ipgre_fill_info`, `erspan_fill_info`). This could lead to data races and corrupted tunnel state. The fix introduces local copies of the flags (`IP_TUNNEL_DECLARE_FLAGS`) which are fully initialized via `ip_tunnel_flags_copy()` (which uses `bitmap_copy()` to copy the entire `unsigned long` array). There is no introduction of uninitialized memory, nor any risk of info-leaks to user space. Standard KASAN/KCSAN and logic testing are sufficient to catch data races and memory corruption. KMSAN is specifically for uninitialized memory and is not applicable here.",
  "NeedsKMSAN": false
}