| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/08/13 13:52 | flow | patch-triage |
4mArgs:null Results: {
"EnableConfigs": [
"BPF_SYSCALL",
"NET"
],
"FocusSymbols": [
"bpf_sk_lookup_tcp",
"bpf_sk_lookup_udp",
"bpf_tc_sk_lookup_tcp",
"bpf_tc_sk_lookup_udp",
"bpf_xdp_sk_lookup_udp",
"bpf_xdp_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_udp",
"sock_map_lookup",
"sock_hash_lookup"
],
"KMSANReasoning": "The patch refactors socket lookup logic in `net/core/filter.c` by extracting `bpf_sk_lookup_full_sk` and modifies socket reference counting in `net/core/sock_map.c` by replacing `refcount_inc_not_zero` with `sock_hold`. These changes are related to object lifetime, reference counting, and potential use-after-free issues. They do not introduce new allocations, modify bounds checking, or expose kernel memory to user space. Any bugs resulting from these changes (such as use-after-free or double free) would be caught by KASAN or standard refcount checking. Therefore, KMSAN is not applicable.",
"NeedsKMSAN": false,
"Reasoning": "The patch modifies BPF socket lookup helpers and BPF sockmap/sockhash map lookup operations. The changes refactor socket reference counting and are reachable from BPF programs and BPF syscalls.",
"WorthFuzzing": true
} |
| 1/1 | 2026/08/13 13:52 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 871892a769cca4c55eab694966a3fe523be6318f\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Thu Aug 13 13:52:25 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/net/core/filter.c b/net/core/filter.c\nindex 3423734124a5b..031fb2aad792a 100644\n--- a/net/core/filter.c\n+++ b/net/core/filter.c\n@@ -7167,6 +7167,28 @@ __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,\n \treturn sk;\n }\n \n+static struct sock *\n+bpf_sk_lookup_full_sk(struct sock *sk)\n+{\n+\tstruct sock *sk2 = sk_to_full_sk(sk);\n+\n+\t/*\n+\t * sk_to_full_sk() may return sk-\u003ersk_listener, make sure the original\n+\t * sk sock refcnt is decremented to prevent a request_sock leak.\n+\t */\n+\tif (sk2 != sk) {\n+\t\tsock_gen_put(sk);\n+\t\t/* Ensure there is no need to bump sk2 refcnt. */\n+\t\tif (unlikely(sk2 \u0026\u0026 !sock_flag(sk2, SOCK_RCU_FREE))) {\n+\t\t\tWARN_ONCE(1, \"Found non-RCU, unreferenced socket!\");\n+\t\t\treturn NULL;\n+\t\t}\n+\t\tsk = sk2;\n+\t}\n+\n+\treturn sk;\n+}\n+\n static struct sock *\n __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,\n \t\tstruct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,\n@@ -7176,22 +7198,8 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,\n \t\t\t\t\t ifindex, proto, netns_id, flags,\n \t\t\t\t\t sdif);\n \n-\tif (sk) {\n-\t\tstruct sock *sk2 = sk_to_full_sk(sk);\n-\n-\t\t/* sk_to_full_sk() may return (sk)-\u003ersk_listener, so make sure the original sk\n-\t\t * sock refcnt is decremented to prevent a request_sock leak.\n-\t\t */\n-\t\tif (sk2 != sk) {\n-\t\t\tsock_gen_put(sk);\n-\t\t\t/* Ensure there is no need to bump sk2 refcnt */\n-\t\t\tif (unlikely(sk2 \u0026\u0026 !sock_flag(sk2, SOCK_RCU_FREE))) {\n-\t\t\t\tWARN_ONCE(1, \"Found non-RCU, unreferenced socket!\");\n-\t\t\t\treturn NULL;\n-\t\t\t}\n-\t\t\tsk = sk2;\n-\t\t}\n-\t}\n+\tif (sk)\n+\t\tsk = bpf_sk_lookup_full_sk(sk);\n \n \treturn sk;\n }\n@@ -7222,22 +7230,8 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,\n \tstruct sock *sk = bpf_skc_lookup(skb, tuple, len, proto, netns_id,\n \t\t\t\t\t flags);\n \n-\tif (sk) {\n-\t\tstruct sock *sk2 = sk_to_full_sk(sk);\n-\n-\t\t/* sk_to_full_sk() may return (sk)-\u003ersk_listener, so make sure the original sk\n-\t\t * sock refcnt is decremented to prevent a request_sock leak.\n-\t\t */\n-\t\tif (sk2 != sk) {\n-\t\t\tsock_gen_put(sk);\n-\t\t\t/* Ensure there is no need to bump sk2 refcnt */\n-\t\t\tif (unlikely(sk2 \u0026\u0026 !sock_flag(sk2, SOCK_RCU_FREE))) {\n-\t\t\t\tWARN_ONCE(1, \"Found non-RCU, unreferenced socket!\");\n-\t\t\t\treturn NULL;\n-\t\t\t}\n-\t\t\tsk = sk2;\n-\t\t}\n-\t}\n+\tif (sk)\n+\t\tsk = bpf_sk_lookup_full_sk(sk);\n \n \treturn sk;\n }\ndiff --git a/net/core/sock_map.c b/net/core/sock_map.c\nindex 9efbd8ca7db83..ca49bc7f8687c 100644\n--- a/net/core/sock_map.c\n+++ b/net/core/sock_map.c\n@@ -392,8 +392,8 @@ static void *sock_map_lookup(struct bpf_map *map, void *key)\n \tsk = __sock_map_lookup_elem(map, *(u32 *)key);\n \tif (!sk)\n \t\treturn NULL;\n-\tif (sk_is_refcounted(sk) \u0026\u0026 !refcount_inc_not_zero(\u0026sk-\u003esk_refcnt))\n-\t\treturn NULL;\n+\tif (sk_is_refcounted(sk))\n+\t\tsock_hold(sk);\n \treturn sk;\n }\n \n@@ -1218,8 +1218,8 @@ static void *sock_hash_lookup(struct bpf_map *map, void *key)\n \tsk = __sock_hash_lookup_elem(map, key);\n \tif (!sk)\n \t\treturn NULL;\n-\tif (sk_is_refcounted(sk) \u0026\u0026 !refcount_inc_not_zero(\u0026sk-\u003esk_refcnt))\n-\t\treturn NULL;\n+\tif (sk_is_refcounted(sk))\n+\t\tsock_hold(sk);\n \treturn sk;\n }\n \n"
} |
| 2/1 | 2026/08/13 13:52 | agent | patch-evaluator |
3mModel:best-expensive Args: null Results: {
"EnableConfigs": [
"BPF_SYSCALL",
"NET"
],
"FocusSymbols": [
"bpf_sk_lookup_tcp",
"bpf_sk_lookup_udp",
"bpf_tc_sk_lookup_tcp",
"bpf_tc_sk_lookup_udp",
"bpf_xdp_sk_lookup_udp",
"bpf_xdp_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_udp",
"sock_map_lookup",
"sock_hash_lookup"
],
"Reasoning": "The patch modifies BPF socket lookup helpers and BPF sockmap/sockhash map lookup operations. The changes refactor socket reference counting and are reachable from BPF programs and BPF syscalls.",
"WorthFuzzing": true
}Instruction: 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. Prompt: For your convenience, here is the diff of the changes:
commit 871892a769cca4c55eab694966a3fe523be6318f
Author: syz-cluster <triage@syzkaller.com>
Date: Thu Aug 13 13:52:25 2026 +0000
syz-cluster: applied patch under review
diff --git a/net/core/filter.c b/net/core/filter.c
index 3423734124a5b..031fb2aad792a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7167,6 +7167,28 @@ __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
return sk;
}
+static struct sock *
+bpf_sk_lookup_full_sk(struct sock *sk)
+{
+ struct sock *sk2 = sk_to_full_sk(sk);
+
+ /*
+ * sk_to_full_sk() may return sk->rsk_listener, make sure the original
+ * sk sock refcnt is decremented to prevent a request_sock leak.
+ */
+ if (sk2 != sk) {
+ sock_gen_put(sk);
+ /* Ensure there is no need to bump sk2 refcnt. */
+ if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) {
+ WARN_ONCE(1, "Found non-RCU, unreferenced socket!");
+ return NULL;
+ }
+ sk = sk2;
+ }
+
+ return sk;
+}
+
static struct sock *
__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
@@ -7176,22 +7198,8 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
ifindex, proto, netns_id, flags,
sdif);
- if (sk) {
- struct sock *sk2 = sk_to_full_sk(sk);
-
- /* sk_to_full_sk() may return (sk)->rsk_listener, so make sure the original sk
- * sock refcnt is decremented to prevent a request_sock leak.
- */
- if (sk2 != sk) {
- sock_gen_put(sk);
- /* Ensure there is no need to bump sk2 refcnt */
- if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) {
- WARN_ONCE(1, "Found non-RCU, unreferenced socket!");
- return NULL;
- }
- sk = sk2;
- }
- }
+ if (sk)
+ sk = bpf_sk_lookup_full_sk(sk);
return sk;
}
@@ -7222,22 +7230,8 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct sock *sk = bpf_skc_lookup(skb, tuple, len, proto, netns_id,
flags);
- if (sk) {
- struct sock *sk2 = sk_to_full_sk(sk);
-
- /* sk_to_full_sk() may return (sk)->rsk_listener, so make sure the original sk
- * sock refcnt is decremented to prevent a request_sock leak.
- */
- if (sk2 != sk) {
- sock_gen_put(sk);
- /* Ensure there is no need to bump sk2 refcnt */
- if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) {
- WARN_ONCE(1, "Found non-RCU, unreferenced socket!");
- return NULL;
- }
- sk = sk2;
- }
- }
+ if (sk)
+ sk = bpf_sk_lookup_full_sk(sk);
return sk;
}
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 9efbd8ca7db83..ca49bc7f8687c 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -392,8 +392,8 @@ static void *sock_map_lookup(struct bpf_map *map, void *key)
sk = __sock_map_lookup_elem(map, *(u32 *)key);
if (!sk)
return NULL;
- if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
- return NULL;
+ if (sk_is_refcounted(sk))
+ sock_hold(sk);
return sk;
}
@@ -1218,8 +1218,8 @@ static void *sock_hash_lookup(struct bpf_map *map, void *key)
sk = __sock_hash_lookup_elem(map, key);
if (!sk)
return NULL;
- if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
- return NULL;
+ if (sk_is_refcounted(sk))
+ sock_hold(sk);
return sk;
}
|
| 3/2 | 2026/08/13 13:52 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 3179 output: 30 thoughts: 436 Thoughts: **Analyzing the BPF Patch** Okay, so I'm looking at this patch and it seems like we have modifications in `net/core/filter.c` and `net/core/sock_map.c`. In `filter.c`, a new helper, `bpf_sk_lookup_full_sk`, has been added. It looks like it's a refactoring of existing lookup functions, specifically `__bpf_sk_lookup` and `bpf_sk_lookup`. Good to see they're cleaning things up. The more interesting part is the change in `sock_map.c`. They've altered `sock_map_lookup` and `sock_hash_lookup`. The key difference is the replacement of the refcount check. Instead of using `refcount_inc_not_zero`, they're now using `sock_hold` within a protected scope. So, essentially, they're assuming the socket is already protected, probably by RCU or something similar, and the `sock_hold` is for maintaining a hold. This is functionally sound, *if* the assumptions about the existing protection are correct. We need to make sure that's the case. Now, let's see if these functions are even reachable. Wait, `sock_map_lookup` and `sock_hash_lookup` are *definitely* used as BPF map lookup functions for `BPF_MAP_TYPE_SOCKMAP` and `BPF_MAP_TYPE_SOCKHASH`. Yup, those are reachable and fuzzeable, no question. Alright, let's look at the config options for `sock_map.c`. Let me quickly look at `net/core/Makefile`... Okay, it looks like `obj-$(CONFIG_BPF_SYSCALL) += sock_map.o`. So, `CONFIG_BPF_SYSCALL` is a requirement. Easy enough to check. Now, let's see about `filter.c`. Same `net/core/Makefile`, and the dependency is `obj-$(CONFIG_BPF_SYSCALL) += filter.o` so `CONFIG_BPF_SYSCALL` applies there too. Hmm, wait. Or maybe the full `net` config is needed for the compile... Let me quickly check the same `Makefile` again to be sure... |
| 4/2 | 2026/08/13 13:53 | tool | grepper |
0mArgs:{
"Expression": "sock_map\\.o",
"PathPrefix": "net/core/Makefile"
}Results: {
"Output": "net/core/Makefile=44=obj-$(CONFIG_NET_SOCK_MSG) += skmsg.o\nnet/core/Makefile:45:obj-$(CONFIG_BPF_SYSCALL) += sock_map.o\nnet/core/Makefile-46-obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o\n"
} |
| 5/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4246 output: 28 thoughts: 40 Thoughts: Here's my take on the thought process: **BPF Configuration Deep Dive** Alright, so I know I need `CONFIG_BPF_SYSCALL` enabled, that much is clear from the dependencies of `sock_map.o`. Now, I need to see what's going on with `filter.o`... I should probably check the `net/core/Makefile` and see how this all fits together. This is where I can get the bigger picture. |
| 6/2 | 2026/08/13 13:53 | tool | grepper |
0mArgs:{
"Expression": "filter\\.o",
"PathPrefix": "net/core/Makefile"
}Results: {
"Output": "net/core/Makefile=12=obj-y\t\t += dev.o dev_api.o dev_addr_lists.o dst.o netevent.o \\\nnet/core/Makefile:13:\t\t\tneighbour.o rtnetlink.o utils.o link_watch.o filter.o \\\nnet/core/Makefile-14-\t\t\tsock_diag.o dev_ioctl.o tso.o sock_reuseport.o \\\n"
} |
| 7/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4530 output: 34 thoughts: 229 Thoughts: **Analyzing BPF Socket Lookup Functionality** Okay, so `filter.o` is definitely compiled when `CONFIG_NET` is enabled, which makes sense. I need to understand the connection between that and the BPF socket lookup functions. Let's start by taking a look at `net/core/filter.c` and specifically focusing on `bpf_sk_lookup_full_sk`, `__bpf_sk_lookup`, and `bpf_sk_lookup`. Ah, right, `bpf_sk_lookup` is a BPF helper, that's key. Now, where do the map operations fit in? I know `sock_map_lookup` and `sock_hash_lookup` are the map operations here. So, the key symbols I need to focus on are `sock_map_lookup`, `sock_hash_lookup`, `bpf_sk_lookup`, and `__bpf_sk_lookup`. Hang on a second, that `bpf_sk_lookup_full_sk` might complicate things because it is static. It's likely inlined or might not even have a distinct symbol address. That means it might not show up directly. However, `sock_map_lookup` and `sock_hash_lookup`, those are also static, but they are *used* as function pointers in `bpf_map_ops`. That means they will not be inlined and *do* have distinct symbol addresses. Okay, I need to verify that those are static and I can proceed from there. |
| 8/2 | 2026/08/13 13:53 | tool | grepper |
0mArgs:{
"Expression": "sock_map_lookup",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=372=static void sock_map_release_progs(struct bpf_map *map)\n--\nnet/core/sock_map.c-376-\nnet/core/sock_map.c:377:static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)\nnet/core/sock_map.c-378-{\n--\nnet/core/sock_map.c-387-\nnet/core/sock_map.c:388:static void *sock_map_lookup(struct bpf_map *map, void *key)\nnet/core/sock_map.c-389-{\n--\nnet/core/sock_map.c-391-\nnet/core/sock_map.c:392:\tsk = __sock_map_lookup_elem(map, *(u32 *)key);\nnet/core/sock_map.c-393-\tif (!sk)\n--\nnet/core/sock_map.c-399-\nnet/core/sock_map.c:400:static void *sock_map_lookup_sys(struct bpf_map *map, void *key)\nnet/core/sock_map.c-401-{\n--\nnet/core/sock_map.c-406-\nnet/core/sock_map.c:407:\tsk = __sock_map_lookup_elem(map, *(u32 *)key);\nnet/core/sock_map.c-408-\tif (!sk)\n--\nnet/core/sock_map.c=647=BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,\n--\nnet/core/sock_map.c-654-\nnet/core/sock_map.c:655:\tsk = __sock_map_lookup_elem(map, key);\nnet/core/sock_map.c-656-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=675=BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,\n--\nnet/core/sock_map.c-682-\nnet/core/sock_map.c:683:\tsk = __sock_map_lookup_elem(map, key);\nnet/core/sock_map.c-684-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=723=static void *sock_map_seq_lookup_elem(struct sock_map_seq_info *info)\n--\nnet/core/sock_map.c-727-\nnet/core/sock_map.c:728:\tinfo-\u003esk = __sock_map_lookup_elem(info-\u003emap, info-\u003eindex);\nnet/core/sock_map.c-729-\n--\nnet/core/sock_map.c=831=const struct bpf_map_ops sock_map_ops = {\n--\nnet/core/sock_map.c-835-\t.map_get_next_key\t= sock_map_get_next_key,\nnet/core/sock_map.c:836:\t.map_lookup_elem_sys_only = sock_map_lookup_sys,\nnet/core/sock_map.c-837-\t.map_update_elem\t= sock_map_update_elem,\nnet/core/sock_map.c-838-\t.map_delete_elem\t= sock_map_delete_elem,\nnet/core/sock_map.c:839:\t.map_lookup_elem\t= sock_map_lookup,\nnet/core/sock_map.c-840-\t.map_release_uref\t= sock_map_release_progs,\n"
} |
| 9/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 6113 output: 33 thoughts: 60 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: **Analyzing BPF Map Lookups and Socket Lookups** Right, so I'm thinking about the implementation details of BPF maps and socket lookups. I see that `sock_map_lookup` and `sock_hash_lookup` are clearly part of the `bpf_map_ops` struct. That means they're not inlined, which is what I'd expect given their function. They're part of a defined set of operations. Now, I'm shifting focus to those BPF socket lookup functions, specifically `bpf_sk_lookup` and `__bpf_sk_lookup`. I need to understand the relationship between these and how they're being leveraged within the BPF framework. Understanding this, I can start to infer implications for performance and, more importantly, the potential for optimization. |
| 10/2 | 2026/08/13 13:53 | tool | grepper |
0mArgs:{
"Expression": "bpf_sk_lookup",
"PathPrefix": "net/core/filter.c"
}Results: {
"Output": "net/core/filter.c=7170=static struct sock *\nnet/core/filter.c:7171:bpf_sk_lookup_full_sk(struct sock *sk)\nnet/core/filter.c-7172-{\n--\nnet/core/filter.c=7192=static struct sock *\nnet/core/filter.c:7193:__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,\nnet/core/filter.c-7194-\t\tstruct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,\n--\nnet/core/filter.c-7201-\tif (sk)\nnet/core/filter.c:7202:\t\tsk = bpf_sk_lookup_full_sk(sk);\nnet/core/filter.c-7203-\n--\nnet/core/filter.c=7226=static struct sock *\nnet/core/filter.c:7227:bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,\nnet/core/filter.c-7228-\t u8 proto, u64 netns_id, u64 flags)\n--\nnet/core/filter.c-7233-\tif (sk)\nnet/core/filter.c:7234:\t\tsk = bpf_sk_lookup_full_sk(sk);\nnet/core/filter.c-7235-\n--\nnet/core/filter.c=7246=static const struct bpf_func_proto bpf_skc_lookup_tcp_proto = {\n--\nnet/core/filter.c-7257-\nnet/core/filter.c:7258:BPF_CALL_5(bpf_sk_lookup_tcp, struct sk_buff *, skb,\nnet/core/filter.c-7259-\t struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)\nnet/core/filter.c-7260-{\nnet/core/filter.c:7261:\treturn (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP,\nnet/core/filter.c-7262-\t\t\t\t\t netns_id, flags);\n--\nnet/core/filter.c-7264-\nnet/core/filter.c:7265:static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = {\nnet/core/filter.c:7266:\t.func\t\t= bpf_sk_lookup_tcp,\nnet/core/filter.c-7267-\t.gpl_only\t= false,\n--\nnet/core/filter.c-7276-\nnet/core/filter.c:7277:BPF_CALL_5(bpf_sk_lookup_udp, struct sk_buff *, skb,\nnet/core/filter.c-7278-\t struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)\nnet/core/filter.c-7279-{\nnet/core/filter.c:7280:\treturn (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP,\nnet/core/filter.c-7281-\t\t\t\t\t netns_id, flags);\n--\nnet/core/filter.c-7283-\nnet/core/filter.c:7284:static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {\nnet/core/filter.c:7285:\t.func\t\t= bpf_sk_lookup_udp,\nnet/core/filter.c-7286-\t.gpl_only\t= false,\n--\nnet/core/filter.c=7320=BPF_CALL_5(bpf_tc_sk_lookup_tcp, struct sk_buff *, skb,\n--\nnet/core/filter.c-7326-\nnet/core/filter.c:7327:\treturn (unsigned long)__bpf_sk_lookup(skb, tuple, len, caller_net,\nnet/core/filter.c-7328-\t\t\t\t\t ifindex, IPPROTO_TCP, netns_id,\n--\nnet/core/filter.c=7344=BPF_CALL_5(bpf_tc_sk_lookup_udp, struct sk_buff *, skb,\n--\nnet/core/filter.c-7350-\nnet/core/filter.c:7351:\treturn (unsigned long)__bpf_sk_lookup(skb, tuple, len, caller_net,\nnet/core/filter.c-7352-\t\t\t\t\t ifindex, IPPROTO_UDP, netns_id,\n--\nnet/core/filter.c=7382=BPF_CALL_5(bpf_xdp_sk_lookup_udp, struct xdp_buff *, ctx,\n--\nnet/core/filter.c-7388-\nnet/core/filter.c:7389:\treturn (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net,\nnet/core/filter.c-7390-\t\t\t\t\t ifindex, IPPROTO_UDP, netns_id,\n--\nnet/core/filter.c=7430=BPF_CALL_5(bpf_xdp_sk_lookup_tcp, struct xdp_buff *, ctx,\n--\nnet/core/filter.c-7436-\nnet/core/filter.c:7437:\treturn (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net,\nnet/core/filter.c-7438-\t\t\t\t\t ifindex, IPPROTO_TCP, netns_id,\n--\nnet/core/filter.c=7474=BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx,\n--\nnet/core/filter.c-7476-{\nnet/core/filter.c:7477:\treturn (unsigned long)__bpf_sk_lookup(NULL, tuple, len,\nnet/core/filter.c-7478-\t\t\t\t\t sock_net(ctx-\u003esk), 0, IPPROTO_TCP,\n--\nnet/core/filter.c=7493=BPF_CALL_5(bpf_sock_addr_sk_lookup_udp, struct bpf_sock_addr_kern *, ctx,\n--\nnet/core/filter.c-7495-{\nnet/core/filter.c:7496:\treturn (unsigned long)__bpf_sk_lookup(NULL, tuple, len,\nnet/core/filter.c-7497-\t\t\t\t\t sock_net(ctx-\u003esk), 0, IPPROTO_UDP,\n--\nnet/core/filter.c=8496=cg_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)\n--\nnet/core/filter.c-8524-\tcase BPF_FUNC_sk_lookup_tcp:\nnet/core/filter.c:8525:\t\treturn \u0026bpf_sk_lookup_tcp_proto;\nnet/core/filter.c-8526-\tcase BPF_FUNC_sk_lookup_udp:\nnet/core/filter.c:8527:\t\treturn \u0026bpf_sk_lookup_udp_proto;\nnet/core/filter.c-8528-\tcase BPF_FUNC_sk_release:\n--\nnet/core/filter.c=8839=sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)\n--\nnet/core/filter.c-8865-\tcase BPF_FUNC_sk_lookup_tcp:\nnet/core/filter.c:8866:\t\treturn \u0026bpf_sk_lookup_tcp_proto;\nnet/core/filter.c-8867-\tcase BPF_FUNC_sk_lookup_udp:\nnet/core/filter.c:8868:\t\treturn \u0026bpf_sk_lookup_udp_proto;\nnet/core/filter.c-8869-\tcase BPF_FUNC_sk_release:\n--\nnet/core/filter.c=11895=const struct bpf_prog_ops sk_reuseport_prog_ops = {\n--\nnet/core/filter.c-11897-\nnet/core/filter.c:11898:DEFINE_STATIC_KEY_FALSE(bpf_sk_lookup_enabled);\nnet/core/filter.c:11899:EXPORT_SYMBOL(bpf_sk_lookup_enabled);\nnet/core/filter.c-11900-\nnet/core/filter.c:11901:BPF_CALL_3(bpf_sk_lookup_assign, struct bpf_sk_lookup_kern *, ctx,\nnet/core/filter.c-11902-\t struct sock *, sk, u64, flags)\n--\nnet/core/filter.c-11929-\nnet/core/filter.c:11930:static const struct bpf_func_proto bpf_sk_lookup_assign_proto = {\nnet/core/filter.c:11931:\t.func\t\t= bpf_sk_lookup_assign,\nnet/core/filter.c-11932-\t.gpl_only\t= false,\n--\nnet/core/filter.c=11940=sk_lookup_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)\n--\nnet/core/filter.c-11945-\tcase BPF_FUNC_sk_assign:\nnet/core/filter.c:11946:\t\treturn \u0026bpf_sk_lookup_assign_proto;\nnet/core/filter.c-11947-\tcase BPF_FUNC_sk_release:\n--\nnet/core/filter.c=11954=static bool sk_lookup_is_valid_access(int off, int size,\n--\nnet/core/filter.c-11958-{\nnet/core/filter.c:11959:\tif (off \u003c 0 || off \u003e= sizeof(struct bpf_sk_lookup))\nnet/core/filter.c-11960-\t\treturn false;\n--\nnet/core/filter.c-11966-\tswitch (off) {\nnet/core/filter.c:11967:\tcase bpf_ctx_range_ptr(struct bpf_sk_lookup, sk):\nnet/core/filter.c-11968-\t\tinfo-\u003ereg_type = PTR_TO_SOCKET_OR_NULL;\n--\nnet/core/filter.c-11970-\nnet/core/filter.c:11971:\tcase bpf_ctx_range(struct bpf_sk_lookup, family):\nnet/core/filter.c:11972:\tcase bpf_ctx_range(struct bpf_sk_lookup, protocol):\nnet/core/filter.c:11973:\tcase bpf_ctx_range(struct bpf_sk_lookup, remote_ip4):\nnet/core/filter.c:11974:\tcase bpf_ctx_range(struct bpf_sk_lookup, local_ip4):\nnet/core/filter.c:11975:\tcase bpf_ctx_range_till(struct bpf_sk_lookup, remote_ip6[0], remote_ip6[3]):\nnet/core/filter.c:11976:\tcase bpf_ctx_range_till(struct bpf_sk_lookup, local_ip6[0], local_ip6[3]):\nnet/core/filter.c:11977:\tcase bpf_ctx_range(struct bpf_sk_lookup, local_port):\nnet/core/filter.c:11978:\tcase bpf_ctx_range(struct bpf_sk_lookup, ingress_ifindex):\nnet/core/filter.c-11979-\t\tbpf_ctx_record_field_size(info, sizeof(__u32));\n--\nnet/core/filter.c-11981-\nnet/core/filter.c:11982:\tcase bpf_ctx_range(struct bpf_sk_lookup, remote_port):\nnet/core/filter.c-11983-\t\t/* Allow 4-byte access to 2-byte field for backward compatibility */\n--\nnet/core/filter.c-11988-\nnet/core/filter.c:11989:\tcase offsetofend(struct bpf_sk_lookup, remote_port) ...\nnet/core/filter.c:11990:\t offsetof(struct bpf_sk_lookup, local_ip4) - 1:\nnet/core/filter.c-11991-\t\t/* Allow access to zero padding for backward compatibility */\n--\nnet/core/filter.c=12000=static u32 sk_lookup_convert_ctx_access(enum bpf_access_type type,\n--\nnet/core/filter.c-12008-\tswitch (si-\u003eoff) {\nnet/core/filter.c:12009:\tcase offsetof(struct bpf_sk_lookup, sk):\nnet/core/filter.c-12010-\t\t*insn++ = BPF_LDX_MEM(BPF_SIZEOF(void *), si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12011:\t\t\t\t offsetof(struct bpf_sk_lookup_kern, selected_sk));\nnet/core/filter.c-12012-\t\tbreak;\nnet/core/filter.c-12013-\nnet/core/filter.c:12014:\tcase offsetof(struct bpf_sk_lookup, family):\nnet/core/filter.c-12015-\t\t*insn++ = BPF_LDX_MEM(BPF_H, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12016:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12017-\t\t\t\t\t\t family, 2, target_size));\n--\nnet/core/filter.c-12019-\nnet/core/filter.c:12020:\tcase offsetof(struct bpf_sk_lookup, protocol):\nnet/core/filter.c-12021-\t\t*insn++ = BPF_LDX_MEM(BPF_H, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12022:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12023-\t\t\t\t\t\t protocol, 2, target_size));\n--\nnet/core/filter.c-12025-\nnet/core/filter.c:12026:\tcase offsetof(struct bpf_sk_lookup, remote_ip4):\nnet/core/filter.c-12027-\t\t*insn++ = BPF_LDX_MEM(BPF_W, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12028:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12029-\t\t\t\t\t\t v4.saddr, 4, target_size));\n--\nnet/core/filter.c-12031-\nnet/core/filter.c:12032:\tcase offsetof(struct bpf_sk_lookup, local_ip4):\nnet/core/filter.c-12033-\t\t*insn++ = BPF_LDX_MEM(BPF_W, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12034:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12035-\t\t\t\t\t\t v4.daddr, 4, target_size));\n--\nnet/core/filter.c-12037-\nnet/core/filter.c:12038:\tcase bpf_ctx_range_till(struct bpf_sk_lookup,\nnet/core/filter.c-12039-\t\t\t\tremote_ip6[0], remote_ip6[3]): {\n--\nnet/core/filter.c-12042-\nnet/core/filter.c:12043:\t\toff -= offsetof(struct bpf_sk_lookup, remote_ip6[0]);\nnet/core/filter.c-12044-\t\toff += bpf_target_off(struct in6_addr, s6_addr32[0], 4, target_size);\nnet/core/filter.c-12045-\t\t*insn++ = BPF_LDX_MEM(BPF_SIZEOF(void *), si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12046:\t\t\t\t offsetof(struct bpf_sk_lookup_kern, v6.saddr));\nnet/core/filter.c-12047-\t\t*insn++ = BPF_JMP_IMM(BPF_JEQ, si-\u003edst_reg, 0, 1);\n--\nnet/core/filter.c-12053-\t}\nnet/core/filter.c:12054:\tcase bpf_ctx_range_till(struct bpf_sk_lookup,\nnet/core/filter.c-12055-\t\t\t\tlocal_ip6[0], local_ip6[3]): {\n--\nnet/core/filter.c-12058-\nnet/core/filter.c:12059:\t\toff -= offsetof(struct bpf_sk_lookup, local_ip6[0]);\nnet/core/filter.c-12060-\t\toff += bpf_target_off(struct in6_addr, s6_addr32[0], 4, target_size);\nnet/core/filter.c-12061-\t\t*insn++ = BPF_LDX_MEM(BPF_SIZEOF(void *), si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12062:\t\t\t\t offsetof(struct bpf_sk_lookup_kern, v6.daddr));\nnet/core/filter.c-12063-\t\t*insn++ = BPF_JMP_IMM(BPF_JEQ, si-\u003edst_reg, 0, 1);\n--\nnet/core/filter.c-12069-\t}\nnet/core/filter.c:12070:\tcase offsetof(struct bpf_sk_lookup, remote_port):\nnet/core/filter.c-12071-\t\t*insn++ = BPF_LDX_MEM(BPF_H, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12072:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12073-\t\t\t\t\t\t sport, 2, target_size));\n--\nnet/core/filter.c-12075-\nnet/core/filter.c:12076:\tcase offsetofend(struct bpf_sk_lookup, remote_port):\nnet/core/filter.c-12077-\t\t*target_size = 2;\n--\nnet/core/filter.c-12080-\nnet/core/filter.c:12081:\tcase offsetof(struct bpf_sk_lookup, local_port):\nnet/core/filter.c-12082-\t\t*insn++ = BPF_LDX_MEM(BPF_H, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12083:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12084-\t\t\t\t\t\t dport, 2, target_size));\n--\nnet/core/filter.c-12086-\nnet/core/filter.c:12087:\tcase offsetof(struct bpf_sk_lookup, ingress_ifindex):\nnet/core/filter.c-12088-\t\t*insn++ = BPF_LDX_MEM(BPF_W, si-\u003edst_reg, si-\u003esrc_reg,\nnet/core/filter.c:12089:\t\t\t\t bpf_target_off(struct bpf_sk_lookup_kern,\nnet/core/filter.c-12090-\t\t\t\t\t\t ingress_ifindex, 4, target_size));\n"
} |
| 11/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 11718 output: 42 thoughts: 467 Thoughts: **Analyzing BPF SK Lookup Functions** Okay, let's break down these `bpf_sk_lookup` functions. My initial observation is that `bpf_sk_lookup` itself is static, but it's clearly being called by `bpf_sk_lookup_tcp` and `bpf_sk_lookup_udp`, which are presented as BPF helpers. Similarly, `__bpf_sk_lookup` is also static, but gets utilized by a wider set of functions like `bpf_tc_sk_lookup_tcp`, `bpf_tc_sk_lookup_udp`, and the XDP and `sock_addr` variants. So, in terms of things to check, the key symbols I need to focus on are: `bpf_sk_lookup_tcp`, `bpf_sk_lookup_udp`, `bpf_tc_sk_lookup_tcp`, `bpf_tc_sk_lookup_udp`, `bpf_xdp_sk_lookup_udp`, `bpf_xdp_sk_lookup_tcp`, `bpf_sock_addr_sk_lookup_tcp`, and `bpf_sock_addr_sk_lookup_udp`. I'm also adding `sock_map_lookup` and `sock_hash_lookup` to the list, just to be thorough. Although, wait... those last two are static but used as function pointers, so they should be okay. Now, looking closer at how these are defined, I see `BPF_CALL_5(...)` being used. That macro expands to things like `bpf_sk_lookup_tcp` or the double-underscore variants, like `____bpf_sk_lookup_tcp`. Right, so it depends on the architecture, but `BPF_CALL_5` actually defines both, right? Let's just avoid the double underscore and focus on the simpler names, like `bpf_sk_lookup_tcp`. My next step is to verify whether these 'primary' functions, like `bpf_sk_lookup_tcp`, are exported or marked as non-static. This is the critical piece to understand their broader availability and potential interactions. |
| 12/2 | 2026/08/13 13:53 | tool | grepper |
0mArgs:{
"Expression": "BPF_CALL_5\\(bpf_sk_lookup_tcp",
"PathPrefix": "net/core/filter.c"
}Results: {
"Output": "net/core/filter.c=7246=static const struct bpf_func_proto bpf_skc_lookup_tcp_proto = {\n--\nnet/core/filter.c-7257-\nnet/core/filter.c:7258:BPF_CALL_5(bpf_sk_lookup_tcp, struct sk_buff *, skb,\nnet/core/filter.c-7259-\t struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)\n"
} |
| 13/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12846 output: 35 thoughts: 29 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Analyzing `BPF_CALL_5`** Okay, hold on a second. When I see `BPF_CALL_5`, my initial assumption is that it's related to some sort of function call within the BPF framework. But is it creating a function or calling one? Given the naming, my intuition leans towards *creating* a function, or at least setting up the means for one. Let's dig deeper and verify that. Time to go hunting for the actual definition of `BPF_CALL_5` to confirm exactly what this macro (or function, I'll find out) is doing. I need to understand its arguments and implications within the broader BPF context. |
| 14/2 | 2026/08/13 13:53 | tool | grepper |
0mError:no matches Args: {
"Expression": "define BPF_CALL_5",
"PathPrefix": "include/linux/bpf.h"
}Results: {
"error": "no matches"
} |
| 15/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 13088 output: 30 thoughts: 24 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **BPF Header Hunt** Okay, so I'm diving into this BPF situation, and I need to zero in on the relevant kernel-level definitions. Where are they likely hiding? My immediate inclination is to check the standard include directories. I'll start with `include/linux/filter.h`. It makes sense, given the historical context of the Berkeley Packet Filter. That's probably where the foundational structures for filtering might reside. If that doesn't immediately yield what I'm looking for, my next move is to go deeper with `include/linux/bpf.h`. That's where I expect to find the more modern and expanded BPF-specific definitions, including the instruction set, helper function prototypes, and likely the core data structures that govern the verifier and JIT compilation. This is the logical path – `filter.h` for the historical grounding, then `bpf.h` for the current implementations. That's the first stop. Let's see what we've got in there. |
| 16/2 | 2026/08/13 13:53 | tool | grepper |
0mArgs:{
"Expression": "define BPF_CALL_",
"PathPrefix": "include/linux/"
}Results: {
"Output": "include/linux/filter.h=40=struct ctl_table_header;\n--\ninclude/linux/filter.h-85-/* unused opcode to mark call to interpreter with arguments */\ninclude/linux/filter.h:86:#define BPF_CALL_ARGS\t0xe0\ninclude/linux/filter.h-87-\n--\ninclude/linux/filter.h=424=static inline int bpf_atomic_load_reg(const struct bpf_insn *insn)\n--\ninclude/linux/filter.h-512-\ninclude/linux/filter.h:513:#define BPF_CALL_REL(TGT)\t\t\t\t\t\\\ninclude/linux/filter.h-514-\t((struct bpf_insn) {\t\t\t\t\t\\\n--\ninclude/linux/filter.h-522-\ninclude/linux/filter.h:523:#define BPF_CALL_IMM(x)\t((void *)(x) - (void *)__bpf_call_base)\ninclude/linux/filter.h-524-\n--\ninclude/linux/filter.h-534-\ninclude/linux/filter.h:535:#define BPF_CALL_KFUNC(OFF, IMM)\t\t\t\t\\\ninclude/linux/filter.h-536-\t((struct bpf_insn) {\t\t\t\t\t\\\n--\ninclude/linux/filter.h-665-\ninclude/linux/filter.h:666:#define BPF_CALL_x(x, attr, name, ...)\t\t\t\t\t \\\ninclude/linux/filter.h-667-\tstatic __always_inline\t\t\t\t\t\t \\\n--\ninclude/linux/filter.h-678-#define __NOATTR\ninclude/linux/filter.h:679:#define BPF_CALL_0(name, ...)\tBPF_CALL_x(0, __NOATTR, name, __VA_ARGS__)\ninclude/linux/filter.h:680:#define BPF_CALL_1(name, ...)\tBPF_CALL_x(1, __NOATTR, name, __VA_ARGS__)\ninclude/linux/filter.h:681:#define BPF_CALL_2(name, ...)\tBPF_CALL_x(2, __NOATTR, name, __VA_ARGS__)\ninclude/linux/filter.h:682:#define BPF_CALL_3(name, ...)\tBPF_CALL_x(3, __NOATTR, name, __VA_ARGS__)\ninclude/linux/filter.h:683:#define BPF_CALL_4(name, ...)\tBPF_CALL_x(4, __NOATTR, name, __VA_ARGS__)\ninclude/linux/filter.h:684:#define BPF_CALL_5(name, ...)\tBPF_CALL_x(5, __NOATTR, name, __VA_ARGS__)\ninclude/linux/filter.h-685-\n"
} |
| 17/2 | 2026/08/13 13:53 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14079 output: 34 thoughts: 14 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Diving into the BPF Call Definition** Okay, so I need to understand this `BPF_CALL_x` macro. My first thought is to dive right into its definition. I'm going to want to see the underlying mechanics – exactly what's being expanded, what registers are involved, the expected arguments, and how it translates into the BPF instruction set. I'm already thinking about potential performance implications based on the type of call this represents. Is it an inline function? Is there a helper function lookup involved? Are there any potential stack frame adjustments? I need to get a handle on the exact instructions generated and understand the ABI. Let's see what we can dig up. |
| 18/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "define BPF_CALL_x",
"PathPrefix": "include/linux/filter.h"
}Results: {
"Output": "include/linux/filter.h=424=static inline int bpf_atomic_load_reg(const struct bpf_insn *insn)\n--\ninclude/linux/filter.h-665-\ninclude/linux/filter.h:666:#define BPF_CALL_x(x, attr, name, ...)\t\t\t\t\t \\\ninclude/linux/filter.h-667-\tstatic __always_inline\t\t\t\t\t\t \\\n"
} |
| 19/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14407 output: 35 thoughts: 20 Thoughts: Here's a summary of my thought process, as requested: **Diving into `filter.h`** Okay, time to get my hands dirty. I need to take a look at the Linux kernel's filtering framework, and I remember there's some crucial stuff defined in `include/linux/filter.h`. Specifically, I have a feeling the details I'm after are around line 666, so I'll jump right to that area. I need to refresh my understanding of how the kernel handles filtering, likely related to networking or security. Let's see what goodies are waiting for me there! I anticipate seeing either critical data structures, enumerations, or definitions related to filtering rules, packet inspection, or perhaps even BPF (Berkeley Packet Filter) integration. Let's get to it. |
| 20/2 | 2026/08/13 13:54 | tool | read-file |
0mArgs:{
"File": "include/linux/filter.h",
"FirstLine": 660,
"LineCount": 20
}Results: {
"Contents": " 660:\t#define __BPF_DECL_REGS(t, a) u64 a\n 661:\t\n 662:\t#define __BPF_PAD(n)\t\t\t\t\t\t\t \\\n 663:\t\t__BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2, \\\n 664:\t\t\t u64, __ur_3, u64, __ur_4, u64, __ur_5)\n 665:\t\n 666:\t#define BPF_CALL_x(x, attr, name, ...)\t\t\t\t\t \\\n 667:\t\tstatic __always_inline\t\t\t\t\t\t \\\n 668:\t\tu64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \\\n 669:\t\ttypedef u64 (*btf_##name)(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \\\n 670:\t\tattr u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \\\n 671:\t\tattr u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \\\n 672:\t\t{\t\t\t\t\t\t\t\t \\\n 673:\t\t\treturn ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\\\n 674:\t\t}\t\t\t\t\t\t\t\t \\\n 675:\t\tstatic __always_inline\t\t\t\t\t\t \\\n 676:\t\tu64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))\n 677:\t\n 678:\t#define __NOATTR\n 679:\t#define BPF_CALL_0(name, ...)\tBPF_CALL_x(0, __NOATTR, name, __VA_ARGS__)\n"
} |
| 21/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 15186 output: 34 thoughts: 215 Thoughts: **Focusing on BPF Socket Lookup Functions** Okay, so I see that `BPF_CALL_5(bpf_sk_lookup_tcp, ...)` is defining both the non-static function `bpf_sk_lookup_tcp(...)` and an internal `static __always_inline u64 ____bpf_sk_lookup_tcp(...)` helper. This means `bpf_sk_lookup_tcp` is likely the primary symbol I should be focusing on for analysis in this context. It's the public-facing entry point. That pattern, naturally, extends to the other related lookup functions: `bpf_sk_lookup_udp`, `bpf_tc_sk_lookup_tcp`, `bpf_tc_sk_lookup_udp`, `bpf_xdp_sk_lookup_udp`, `bpf_xdp_sk_lookup_tcp`, `bpf_sock_addr_sk_lookup_tcp`, and `bpf_sock_addr_sk_lookup_udp`. They'll all follow the same structure. Now, let's pivot and check how these lookup functions interact with the socket maps. I'll need to dive into `sock_map_lookup` and `sock_hash_lookup` within `net/core/sock_map.c`. That should provide insights into the internal workings and potential performance characteristics. |
| 22/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "sock_map_lookup",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=372=static void sock_map_release_progs(struct bpf_map *map)\n--\nnet/core/sock_map.c-376-\nnet/core/sock_map.c:377:static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)\nnet/core/sock_map.c-378-{\n--\nnet/core/sock_map.c-387-\nnet/core/sock_map.c:388:static void *sock_map_lookup(struct bpf_map *map, void *key)\nnet/core/sock_map.c-389-{\n--\nnet/core/sock_map.c-391-\nnet/core/sock_map.c:392:\tsk = __sock_map_lookup_elem(map, *(u32 *)key);\nnet/core/sock_map.c-393-\tif (!sk)\n--\nnet/core/sock_map.c-399-\nnet/core/sock_map.c:400:static void *sock_map_lookup_sys(struct bpf_map *map, void *key)\nnet/core/sock_map.c-401-{\n--\nnet/core/sock_map.c-406-\nnet/core/sock_map.c:407:\tsk = __sock_map_lookup_elem(map, *(u32 *)key);\nnet/core/sock_map.c-408-\tif (!sk)\n--\nnet/core/sock_map.c=647=BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,\n--\nnet/core/sock_map.c-654-\nnet/core/sock_map.c:655:\tsk = __sock_map_lookup_elem(map, key);\nnet/core/sock_map.c-656-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=675=BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,\n--\nnet/core/sock_map.c-682-\nnet/core/sock_map.c:683:\tsk = __sock_map_lookup_elem(map, key);\nnet/core/sock_map.c-684-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=723=static void *sock_map_seq_lookup_elem(struct sock_map_seq_info *info)\n--\nnet/core/sock_map.c-727-\nnet/core/sock_map.c:728:\tinfo-\u003esk = __sock_map_lookup_elem(info-\u003emap, info-\u003eindex);\nnet/core/sock_map.c-729-\n--\nnet/core/sock_map.c=831=const struct bpf_map_ops sock_map_ops = {\n--\nnet/core/sock_map.c-835-\t.map_get_next_key\t= sock_map_get_next_key,\nnet/core/sock_map.c:836:\t.map_lookup_elem_sys_only = sock_map_lookup_sys,\nnet/core/sock_map.c-837-\t.map_update_elem\t= sock_map_update_elem,\nnet/core/sock_map.c-838-\t.map_delete_elem\t= sock_map_delete_elem,\nnet/core/sock_map.c:839:\t.map_lookup_elem\t= sock_map_lookup,\nnet/core/sock_map.c-840-\t.map_release_uref\t= sock_map_release_progs,\n"
} |
| 23/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 16723 output: 34 thoughts: 139 Thoughts: **Examining the `sock_map_lookup` and `sock_hash_lookup` Functions** Okay, so I'm looking at these `sock_map_lookup` and `sock_hash_lookup` functions. They're declared as `static`, which immediately raises a flag. They're being used as function pointers within `sock_map_ops` and `sock_hash_ops`, which is pretty standard. But that `static` qualifier... if the compiler decided to inline them, syzkaller, our fuzzer, might have trouble resolving their addresses. However, since the code takes their addresses, inlining is probably not happening. Still, syzkaller tends to prefer non-static functions, for easier instrumentation. So, the question becomes, is there an alternative? Can we leverage a non-static version? Are `sock_map_ops` and `sock_hash_ops` themselves exported, or at least not declared as `static`? I need to verify. Let's start by checking `sock_map_ops`. I need to confirm whether we can avoid these potentially problematic static functions. |
| 24/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "sock_map_ops",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=830=BTF_ID_LIST_SINGLE(sock_map_btf_ids, struct, bpf_stab)\nnet/core/sock_map.c:831:const struct bpf_map_ops sock_map_ops = {\nnet/core/sock_map.c-832-\t.map_meta_equal\t\t= bpf_map_meta_equal,\n"
} |
| 25/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 17249 output: 34 thoughts: 23 Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal reflection: **Contemplating Socket Operation Scope** Hmm, so `sock_map_ops` is declared as non-static. That's interesting, but not entirely surprising given its likely usage context, probably needing access across modules or within a complex socket implementation. It implies some level of external interaction or dependency, which makes sense if the intention is for it to be a more generalized, potentially extensible interface. Now, that gets me thinking...what's the story with `sock_hash_ops`? Is *that* non-static as well? The implications are immediately relevant if we're dealing with a distributed system or concurrency. The non-static nature of the former implies that these `ops` structures probably play a pretty important part in the core logic. Are we dealing with something that requires dynamic registration and discovery? Or, is it perhaps used by things outside of its originating file? This line of questioning will probably tell me the architecture of the related code. I should probably dig in and investigate if my intuition is correct. |
| 26/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "sock_hash_ops",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=1446=BTF_ID_LIST_SINGLE(sock_hash_map_btf_ids, struct, bpf_shtab)\nnet/core/sock_map.c:1447:const struct bpf_map_ops sock_hash_ops = {\nnet/core/sock_map.c-1448-\t.map_meta_equal\t\t= bpf_map_meta_equal,\n"
} |
| 27/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 17660 output: 29 thoughts: 142 Thoughts: **My BPF Map Ops Analysis** Okay, so I'm looking at these `const struct bpf_map_ops`, and the first thing that jumps out is that I need to include `sock_map_lookup` and `sock_hash_lookup` in my analysis of key symbols. Even though they're probably static within the larger context, the fact that they're used as function pointers means they'll have distinct addresses, and I need to account for that. Now, I need to make sure I haven't missed any vital configuration options. Clearly, `CONFIG_BPF_SYSCALL` is essential for `sock_map.o`, but what about its dependencies? Right, `CONFIG_NET` has to be enabled too, it's a parent config. I should double-check that I haven't forgotten anything else. Let me dig into `net/core/Kconfig` and see if `sock_map.o` or `filter.o` are mentioned anywhere else. That should uncover anything I might have missed. |
| 28/2 | 2026/08/13 13:54 | tool | grepper |
0mError:no matches Args: {
"Expression": "sock_map",
"PathPrefix": "net/core/Kconfig"
}Results: {
"error": "no matches"
} |
| 29/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 18070 output: 31 thoughts: 19 Thoughts: Here's my thought process, as it relates to checking `init/Kconfig` for `BPF_SYSCALL`: **Checking `init/Kconfig` for `BPF_SYSCALL`** Okay, so I need to find the configuration option `BPF_SYSCALL`. My immediate thought is, "Where would this configuration be defined?" Given that it's a fundamental system-level feature, it makes sense to start with `init/Kconfig`. That's the logical place to check, the starting point for a system-level configuration option like this. Let's see what's in there. I'll need to open the file and look for the definition, or perhaps a relevant `config` block. It could be directly defined, or potentially included from another Kconfig file. I'm expecting it to be relatively straightforward; a simple `config BPF_SYSCALL` and some associated help text defining what the option controls. Time to dive in. |
| 30/2 | 2026/08/13 13:54 | tool | grepper |
0mError:no matches Args: {
"Expression": "config BPF_SYSCALL",
"PathPrefix": "init/Kconfig"
}Results: {
"error": "no matches"
} |
| 31/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 18344 output: 27 thoughts: 16 Thoughts: Here's my summary, as though I'm thinking it: **Digging into the BPF Configuration** Okay, so I need to figure out where this particular BPF-related configuration is defined. My first instinct, and a pretty reliable one given my experience, is to jump straight into the kernel's configuration files. Let's start with `kernel/bpf/Kconfig`. That's where the core BPF options are usually located, or at least where I'd expect to find the links to the relevant sub-configurations. I'll likely check similar files too, just in case, but `kernel/bpf/Kconfig` is definitely the prime suspect for getting me started. This should be a quick win if I'm lucky. |
| 32/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "config BPF_SYSCALL",
"PathPrefix": ""
}Results: {
"Output": "kernel/bpf/Kconfig=25=menu \"BPF subsystem\"\nkernel/bpf/Kconfig-26-\nkernel/bpf/Kconfig:27:config BPF_SYSCALL\nkernel/bpf/Kconfig-28-\tbool \"Enable bpf() system call\"\n"
} |
| 33/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 18631 output: 34 thoughts: 24 Thoughts: Here's a summary of my thought process: **Diving into BPF Syscall Configuration** Okay, so I need to understand the configuration dependencies for `BPF_SYSCALL`. My first move is clear: I'm going straight to `kernel/bpf/Kconfig`. That's where all the relevant kernel configuration options related to BPF are defined. I know that's where I'll find the dependencies I need to assess. There isn't much more to it - time to dig in. |
| 34/2 | 2026/08/13 13:54 | tool | read-file |
0mArgs:{
"File": "kernel/bpf/Kconfig",
"FirstLine": 25,
"LineCount": 20
}Results: {
"Contents": " 25:\tmenu \"BPF subsystem\"\n 26:\t\n 27:\tconfig BPF_SYSCALL\n 28:\t\tbool \"Enable bpf() system call\"\n 29:\t\tselect BPF\n 30:\t\tselect IRQ_WORK\n 31:\t\tselect NEED_TASKS_RCU\n 32:\t\tselect TASKS_TRACE_RCU\n 33:\t\tselect BINARY_PRINTF\n 34:\t\tselect NET_SOCK_MSG if NET\n 35:\t\tselect NET_XGRESS if NET\n 36:\t\tselect PAGE_POOL if NET\n 37:\t\tdefault n\n 38:\t\thelp\n 39:\t\t Enable the bpf() system call that allows to manipulate BPF programs\n 40:\t\t and maps via file descriptors.\n 41:\t\n 42:\tconfig BPF_JIT\n 43:\t\tbool \"Enable BPF Just In Time compiler\"\n 44:\t\tdepends on BPF\n"
} |
| 35/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 19051 output: 44 thoughts: 595 Thoughts: **My BPF Lookup Analysis** Okay, so I'm digging into these BPF lookup functions, and here's what I've got so far. It looks like the core configuration I need to be concerned with is `BPF_SYSCALL`, and I'll also require `NET` due to its influence on `net/core/filter.c` and `net/core/sock_map.c`. Specifically, I noticed that `sock_map.c` is compiled when `CONFIG_BPF_SYSCALL` is enabled and `filter.c` when `CONFIG_NET` is enabled, which implies that both `BPF_SYSCALL` and `NET` are necessary. Now, let's look at the symbols I need to focus on: * `bpf_sk_lookup_tcp`, `bpf_sk_lookup_udp` * `bpf_tc_sk_lookup_tcp`, `bpf_tc_sk_lookup_udp` * `bpf_xdp_sk_lookup_udp`, `bpf_xdp_sk_lookup_tcp` * `bpf_sock_addr_sk_lookup_tcp`, `bpf_sock_addr_sk_lookup_udp` * `sock_map_lookup`, `sock_hash_lookup` Aha! `sock_map_lookup` and `sock_hash_lookup` are static, which may impact how I approach fuzzing them with Syzkaller, unless there are non-static wrappers. Let's see... looking at `sock_map_ops` and `sock_hash_ops`, these are structs. Right, so the BPF map lookup syscall ultimately calls `map->ops->map_lookup_elem`. This implies that `sock_map_lookup` and `sock_hash_lookup` are going to be called internally via that mechanism, which is promising. Syzkaller should be able to get to them if they are in the list. Okay, let's just quickly double check that `bpf_sk_lookup_tcp` is non-static as I suspect. It looks like the `BPF_CALL_5` macro expands to a non-static declaration: ```c u64 bpf_sk_lookup_tcp(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); ``` Yes, this is non-static! Excellent. Now I need to repeat that check for `bpf_tc_sk_lookup_tcp` and ensure that it too is non-static, but I'm confident now. |
| 36/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "BPF_CALL_5\\(bpf_tc_sk_lookup_tcp",
"PathPrefix": "net/core/filter.c"
}Results: {
"Output": "net/core/filter.c=7308=static const struct bpf_func_proto bpf_tc_skc_lookup_tcp_proto = {\n--\nnet/core/filter.c-7319-\nnet/core/filter.c:7320:BPF_CALL_5(bpf_tc_sk_lookup_tcp, struct sk_buff *, skb,\nnet/core/filter.c-7321-\t struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)\n"
} |
| 37/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 20427 output: 45 thoughts: 29 Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue: **Checking `bpf_xdp_sk_lookup_tcp`'s Visibility** Alright, that confirmation feels good. Now, I need to be absolutely certain about something. Is `bpf_xdp_sk_lookup_tcp` declared with the `static` keyword? That's the critical question here. I need to quickly verify its linkage and scope. If it *is* static, it introduces some design limitations that I need to be aware of and consider when formulating my next steps. If not, then I can move forward with my existing hypothesis. A quick check of the relevant header files, and I should have the answer. This is an important detail I'm relying on, so it’s something I need to make sure I am getting right. |
| 38/2 | 2026/08/13 13:54 | tool | grepper |
0mArgs:{
"Expression": "BPF_CALL_5\\(bpf_xdp_sk_lookup_tcp",
"PathPrefix": "net/core/filter.c"
}Results: {
"Output": "net/core/filter.c=7418=static const struct bpf_func_proto bpf_xdp_skc_lookup_tcp_proto = {\n--\nnet/core/filter.c-7429-\nnet/core/filter.c:7430:BPF_CALL_5(bpf_xdp_sk_lookup_tcp, struct xdp_buff *, ctx,\nnet/core/filter.c-7431-\t struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags)\n"
} |
| 39/2 | 2026/08/13 13:54 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 20838 output: 46 thoughts: 30 Thoughts: Okay, here's my summary, in the first person, as an expert in my field, reflecting on the provided thought process: **Verification of `bpf_sock_addr_sk_lookup_tcp` Non-Static Status** Alright, that's correct, confirmed. Now, let's just make sure that `bpf_sock_addr_sk_lookup_tcp` function is *not* declared as static. This is essential for whatever I'm working on to properly link and access the function from other parts of the code. We need to be able to call it. |
| 40/2 | 2026/08/13 13:55 | tool | grepper |
0mArgs:{
"Expression": "BPF_CALL_5\\(bpf_sock_addr_sk_lookup_tcp",
"PathPrefix": "net/core/filter.c"
}Results: {
"Output": "net/core/filter.c=7463=static const struct bpf_func_proto bpf_sock_addr_skc_lookup_tcp_proto = {\n--\nnet/core/filter.c-7473-\nnet/core/filter.c:7474:BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx,\nnet/core/filter.c-7475-\t struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)\n"
} |
| 41/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 21201 output: 37 thoughts: 21 Thoughts: **Checking the Static Nature of a Function** Yes, that's right, absolutely. Okay, now let's just quickly verify something crucial for how I'm thinking about this. I need to confirm whether `sock_map_lookup` is actually declared as `static`. I know it's probably obvious, but it's always best to be thorough, especially when dealing with core components like this. A quick check will help to avoid assumptions that could create problems later on. |
| 42/2 | 2026/08/13 13:55 | tool | grepper |
0mArgs:{
"Expression": "static void \\*sock_map_lookup",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=377=static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)\n--\nnet/core/sock_map.c-387-\nnet/core/sock_map.c:388:static void *sock_map_lookup(struct bpf_map *map, void *key)\nnet/core/sock_map.c-389-{\n--\nnet/core/sock_map.c-399-\nnet/core/sock_map.c:400:static void *sock_map_lookup_sys(struct bpf_map *map, void *key)\nnet/core/sock_map.c-401-{\n"
} |
| 43/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 21552 output: 33 thoughts: 85 Thoughts: **Analyzing the Static Function Pointer** Okay, so I see this code, and the first thing that jumps out is that it's static. But, wait a minute, it's also being used as a function pointer. That raises a flag. I need to figure out *why* a static function is being used in this way. The key question is: Is there any non-static function that actually calls it? This is crucial for understanding its scope and purpose within the broader architecture. Ah, I remember that the BPF map lookup, the syscall, ultimately calls `map->ops->map_lookup_elem`. Okay, that's the connection! Let me see, the syscall entry point itself for this is `map_lookup_elem` in `kernel/bpf/syscall.c`. Right, so to trace this, I need to check `kernel/bpf/syscall.c` now. Let me open that file and see how this all connects. This should give me the answers I need. |
| 44/2 | 2026/08/13 13:55 | tool | grepper |
0mArgs:{
"Expression": "map_lookup_elem",
"PathPrefix": "kernel/bpf/syscall.c"
}Results: {
"Output": "kernel/bpf/syscall.c=308=static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value,\n--\nkernel/bpf/syscall.c-327-\t} else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) {\nkernel/bpf/syscall.c:328:\t\terr = bpf_fd_array_map_lookup_elem(map, key, value);\nkernel/bpf/syscall.c-329-\t} else if (IS_FD_HASH(map)) {\nkernel/bpf/syscall.c:330:\t\terr = bpf_fd_htab_map_lookup_elem(map, key, value);\nkernel/bpf/syscall.c-331-\t} else if (map-\u003emap_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {\n--\nkernel/bpf/syscall.c-341-\t\trcu_read_lock();\nkernel/bpf/syscall.c:342:\t\tif (map-\u003eops-\u003emap_lookup_elem_sys_only)\nkernel/bpf/syscall.c:343:\t\t\tptr = map-\u003eops-\u003emap_lookup_elem_sys_only(map, key);\nkernel/bpf/syscall.c-344-\t\telse\nkernel/bpf/syscall.c:345:\t\t\tptr = map-\u003eops-\u003emap_lookup_elem(map, key);\nkernel/bpf/syscall.c-346-\t\tif (IS_ERR(ptr)) {\n--\nkernel/bpf/syscall.c=1760=static void *___bpf_copy_key(bpfptr_t ukey, u64 key_size)\n--\nkernel/bpf/syscall.c-1773-\nkernel/bpf/syscall.c:1774:static int map_lookup_elem(union bpf_attr *attr)\nkernel/bpf/syscall.c-1775-{\n--\nkernel/bpf/syscall.c=6294=static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,\n--\nkernel/bpf/syscall.c-6337-\tcase BPF_MAP_LOOKUP_ELEM:\nkernel/bpf/syscall.c:6338:\t\terr = map_lookup_elem(\u0026attr);\nkernel/bpf/syscall.c-6339-\t\tbreak;\n"
} |
| 45/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 22504 output: 37 thoughts: 326 Thoughts: **Analyzing the sock_map Lookup Process for Syzkaller Integration** Okay, so I'm digging into how the `sock_map` lookup works, specifically within the BPF context and how Syzkaller could interact with it. I see that `kernel/bpf/syscall.c` uses `map_lookup_elem` which then dispatches to either `map->ops->map_lookup_elem_sys_only` or `map->ops->map_lookup_elem`. For `sock_map`, the `sys_only` version translates to `sock_map_lookup_sys`. But wait a minute... `sock_map_lookup_sys` is *also* static? That's not ideal for Syzkaller's symbol resolution, especially if it gets inlined. The regular `sock_map_lookup` function gets called by BPF helpers like `bpf_sk_redirect_map` and `bpf_msg_redirect_map`, but `bpf_sk_redirect_map` calls `__sock_map_lookup_elem`, so that's a dead end. Right, so `sock_map_lookup` is *only* called via `map->ops->map_lookup_elem`. The issue is, since it's static, Syzkaller might have trouble resolving it, particularly if the compiler decides to inline it. However, since we're taking the address of `sock_map_lookup`, inlining is less likely, but still a concern. It *could* work if we explicitly provide it as a focus symbol to Syzkaller, but it's always cleaner and more robust to use non-static functions if possible. So, the question is, is there any non-static function we *can* use? `sock_map_ops` is non-static, but it's a struct and not a function. I need to look for any functions in `net/core/sock_map.c` that directly or indirectly call either `sock_map_lookup` or `__sock_map_lookup_elem`. This will be my next area to investigate. |
| 46/2 | 2026/08/13 13:55 | tool | grepper |
0mArgs:{
"Expression": "__sock_map_lookup_elem",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=372=static void sock_map_release_progs(struct bpf_map *map)\n--\nnet/core/sock_map.c-376-\nnet/core/sock_map.c:377:static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)\nnet/core/sock_map.c-378-{\n--\nnet/core/sock_map.c=388=static void *sock_map_lookup(struct bpf_map *map, void *key)\n--\nnet/core/sock_map.c-391-\nnet/core/sock_map.c:392:\tsk = __sock_map_lookup_elem(map, *(u32 *)key);\nnet/core/sock_map.c-393-\tif (!sk)\n--\nnet/core/sock_map.c=400=static void *sock_map_lookup_sys(struct bpf_map *map, void *key)\n--\nnet/core/sock_map.c-406-\nnet/core/sock_map.c:407:\tsk = __sock_map_lookup_elem(map, *(u32 *)key);\nnet/core/sock_map.c-408-\tif (!sk)\n--\nnet/core/sock_map.c=647=BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,\n--\nnet/core/sock_map.c-654-\nnet/core/sock_map.c:655:\tsk = __sock_map_lookup_elem(map, key);\nnet/core/sock_map.c-656-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=675=BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,\n--\nnet/core/sock_map.c-682-\nnet/core/sock_map.c:683:\tsk = __sock_map_lookup_elem(map, key);\nnet/core/sock_map.c-684-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=723=static void *sock_map_seq_lookup_elem(struct sock_map_seq_info *info)\n--\nnet/core/sock_map.c-727-\nnet/core/sock_map.c:728:\tinfo-\u003esk = __sock_map_lookup_elem(info-\u003emap, info-\u003eindex);\nnet/core/sock_map.c-729-\n"
} |
| 47/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 24019 output: 34 thoughts: 295 Thoughts: **My Analysis of the BPF Map Lookup Change** Okay, so I'm looking at this patch and initially, I see that `bpf_sk_redirect_map` and `bpf_msg_redirect_map` are *not* declared static. That's a point of interest, but then I remember, this patch is actually modifying `sock_map_lookup` and `sock_hash_lookup`, not the lower-level `__sock_map_lookup_elem` function. Right, I see the diff now. They've changed the refcounting in `sock_map_lookup`. Instead of `refcount_inc_not_zero`, they're using `sock_hold`. Makes sense, that's the intended method of bumping the reference count. Aha! So the crucial change is within `sock_map_lookup` and `sock_hash_lookup`. Thinking more about how BPF maps work, I realize that `sock_map_lookup` and `sock_hash_lookup` are the entry points because they're called via `map->ops->map_lookup_elem`. This is where the action is happening. Perfect! That's my target. The good news is, my focus can remain on these two functions; `sock_map_lookup` and `sock_hash_lookup`. They're the ones I need to examine closely. And, because of how Syzkaller and kcov work, the coverage will still be tracked for them, even with these changes deeper down in the stack. I'll make sure to double-check `sock_hash_lookup` too, just to be sure. |
| 48/2 | 2026/08/13 13:55 | tool | grepper |
0mArgs:{
"Expression": "sock_hash_lookup",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"Output": "net/core/sock_map.c=880=static struct bpf_shtab_elem *\nnet/core/sock_map.c:881:sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key,\nnet/core/sock_map.c-882-\t\t\t u32 key_size)\n--\nnet/core/sock_map.c-894-\nnet/core/sock_map.c:895:static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key)\nnet/core/sock_map.c-896-{\n--\nnet/core/sock_map.c-905-\tbucket = sock_hash_select_bucket(htab, hash);\nnet/core/sock_map.c:906:\telem = sock_hash_lookup_elem_raw(\u0026bucket-\u003ehead, hash, key, key_size);\nnet/core/sock_map.c-907-\n--\nnet/core/sock_map.c=918=static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk,\n--\nnet/core/sock_map.c-932-\tspin_lock_bh(\u0026bucket-\u003elock);\nnet/core/sock_map.c:933:\telem_probe = sock_hash_lookup_elem_raw(\u0026bucket-\u003ehead, elem-\u003ehash,\nnet/core/sock_map.c-934-\t\t\t\t\t elem-\u003ekey, map-\u003ekey_size);\n--\nnet/core/sock_map.c=943=static long sock_hash_delete_elem(struct bpf_map *map, void *key)\n--\nnet/core/sock_map.c-954-\tspin_lock_bh(\u0026bucket-\u003elock);\nnet/core/sock_map.c:955:\telem = sock_hash_lookup_elem_raw(\u0026bucket-\u003ehead, hash, key, key_size);\nnet/core/sock_map.c-956-\tif (elem) {\n--\nnet/core/sock_map.c=993=static int sock_hash_update_common(struct bpf_map *map, void *key,\n--\nnet/core/sock_map.c-1022-\tspin_lock_bh(\u0026bucket-\u003elock);\nnet/core/sock_map.c:1023:\telem = sock_hash_lookup_elem_raw(\u0026bucket-\u003ehead, hash, key, key_size);\nnet/core/sock_map.c-1024-\tif (elem \u0026\u0026 flags == BPF_NOEXIST) {\n--\nnet/core/sock_map.c=1058=static int sock_hash_get_next_key(struct bpf_map *map, void *key,\n--\nnet/core/sock_map.c-1070-\thead = \u0026sock_hash_select_bucket(htab, hash)-\u003ehead;\nnet/core/sock_map.c:1071:\telem = sock_hash_lookup_elem_raw(head, hash, key, key_size);\nnet/core/sock_map.c-1072-\tif (!elem)\n--\nnet/core/sock_map.c=1146=static void sock_hash_free(struct bpf_map *map)\n--\nnet/core/sock_map.c-1198-\nnet/core/sock_map.c:1199:static void *sock_hash_lookup_sys(struct bpf_map *map, void *key)\nnet/core/sock_map.c-1200-{\n--\nnet/core/sock_map.c-1205-\nnet/core/sock_map.c:1206:\tsk = __sock_hash_lookup_elem(map, key);\nnet/core/sock_map.c-1207-\tif (!sk)\n--\nnet/core/sock_map.c-1213-\nnet/core/sock_map.c:1214:static void *sock_hash_lookup(struct bpf_map *map, void *key)\nnet/core/sock_map.c-1215-{\n--\nnet/core/sock_map.c-1217-\nnet/core/sock_map.c:1218:\tsk = __sock_hash_lookup_elem(map, key);\nnet/core/sock_map.c-1219-\tif (!sk)\n--\nnet/core/sock_map.c=1253=BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb,\n--\nnet/core/sock_map.c-1260-\nnet/core/sock_map.c:1261:\tsk = __sock_hash_lookup_elem(map, key);\nnet/core/sock_map.c-1262-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=1281=BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg,\n--\nnet/core/sock_map.c-1288-\nnet/core/sock_map.c:1289:\tsk = __sock_hash_lookup_elem(map, key);\nnet/core/sock_map.c-1290-\tif (unlikely(!sk || !sock_map_redirect_allowed(sk)))\n--\nnet/core/sock_map.c=1447=const struct bpf_map_ops sock_hash_ops = {\n--\nnet/core/sock_map.c-1453-\t.map_delete_elem\t= sock_hash_delete_elem,\nnet/core/sock_map.c:1454:\t.map_lookup_elem\t= sock_hash_lookup,\nnet/core/sock_map.c:1455:\t.map_lookup_elem_sys_only = sock_hash_lookup_sys,\nnet/core/sock_map.c-1456-\t.map_release_uref\t= sock_hash_release_progs,\n"
} |
| 49/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 26247 output: 39 thoughts: 371 Thoughts: **My Analysis of BPF Socket Lookup Functionality** Okay, so I'm digging into this code and, as expected, `sock_hash_lookup` is indeed a static function within `sock_hash_ops`. That's straightforward enough. Now, let me see... I need to also consider `bpf_sk_lookup_full_sk`, which is also static and called by `__bpf_sk_lookup` and `bpf_sk_lookup`. Ah, this patch is introducing that. So the core of the matter, what I *really* need to focus on, are the BPF helpers that utilize `__bpf_sk_lookup` and `bpf_sk_lookup` directly. Let's see... those would be: * `bpf_sk_lookup_tcp` * `bpf_sk_lookup_udp` * `bpf_tc_sk_lookup_tcp` * `bpf_tc_sk_lookup_udp` * `bpf_xdp_sk_lookup_udp` * `bpf_xdp_sk_lookup_tcp` * `bpf_sock_addr_sk_lookup_tcp` * `bpf_sock_addr_sk_lookup_udp` * `sock_map_lookup` * `sock_hash_lookup` I'll add those to the FocusSymbols list right away. And, of course, the relevant configurations here are `BPF_SYSCALL` and `NET`. Just to be absolutely certain, let's confirm the name again, it seems right, I'll check that `bpf_sk_lookup_tcp` *is* actually the correct name... Yep, `BPF_CALL_5(bpf_sk_lookup_tcp, ...)` confirms it. So, that's defined correctly. Excellent, let's now check if `bpf_sk_lookup_tcp` is exported. |
| 50/2 | 2026/08/13 13:55 | tool | grepper |
0mError:no matches Args: {
"Expression": "EXPORT_SYMBOL.*bpf_sk_lookup_tcp",
"PathPrefix": "net/core/filter.c"
}Results: {
"error": "no matches"
} |
| 51/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 27108 output: 38 thoughts: 41 Thoughts: Okay, here's my interpretation of those thoughts, summarized from my perspective as a field expert: **Investigating a Fuzzing Target** Alright, so the function I'm looking at isn't *explicitly* exported, but it's not declared as `static`. That's interesting. The good news is, if it's non-static, Syzkaller *should* be able to target it for fuzzing. That's the key point: Syzkaller’s capabilities extend beyond just explicitly exported symbols. So, the immediate next step is clear: I need to verify whether the `sock_map_lookup` function is actually exported. That's the piece of information I need to confirm whether this is a viable fuzzing target or if I need to do some more digging. |
| 52/2 | 2026/08/13 13:55 | tool | grepper |
0mError:no matches Args: {
"Expression": "EXPORT_SYMBOL.*sock_map_lookup",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"error": "no matches"
} |
| 53/2 | 2026/08/13 13:55 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 27372 output: 38 thoughts: 21 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: **Debugging a Stalled Process** Alright, this feels…stuck. Dead in the water. Everything’s just *static*. No apparent movement, no obvious progress. Before I start tearing into the kernel with strace or gdb, I'm going to take a slightly more surgical approach. The problem could lie in a lot of places, but given the symptoms, my gut says there's a potential issue related to socket management. Specifically, I need to know if `sock_hash_lookup` is accessible from where I'm suspecting the process is hung. Is that symbol exported in the kernel image for this build? I need to check the symbol table directly, because if that's not exposed, my debugging is going to take a completely different (and more painful) track. Let's see if that's exposed... |
| 54/2 | 2026/08/13 13:56 | tool | grepper |
0mError:no matches Args: {
"Expression": "EXPORT_SYMBOL.*sock_hash_lookup",
"PathPrefix": "net/core/sock_map.c"
}Results: {
"error": "no matches"
} |
| 55/2 | 2026/08/13 13:56 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 27638 output: 204 thoughts: 901 Thoughts: **Analyzing the BPF Code Changes** Okay, first things first, this feels pretty straightforward, but let's be methodical. Initially, I thought I needed to include several BPF functions (`bpf_sk_redirect_map`, `bpf_msg_redirect_map`, etc.) because they relate to lookups. However, those functions ultimately call `__sock_map_lookup_elem` and `__sock_hash_lookup_elem`, but I realize now that those aren't *directly* where the code was modified. The actual changes are within `sock_map_lookup` and `sock_hash_lookup`. So, I'll restrict my focus to those two functions, as that's where the relevant logic resides. Now, let's confirm the modification in the provided patch. Yes, the change is indeed within `sock_map_lookup` and similarly in `sock_hash_lookup`. I need to ensure I fully grasp the impact here. Next, I need to understand the call paths. I've confirmed that `sock_map_lookup` is called within the `sock_map_ops` structure. This structure is tied to `BPF_MAP_TYPE_SOCKMAP`. Therefore, the modified code within `sock_map_lookup` and `sock_hash_lookup` will be executed by BPF programs that perform map lookups on `BPF_MAP_TYPE_SOCKMAP` and `BPF_MAP_TYPE_SOCKHASH`. From a fuzzing perspective, this is very interesting. Syzkaller can easily target this by creating a `BPF_MAP_TYPE_SOCKMAP` and calling `bpf_map_lookup_elem` from a BPF program. I need to make sure I understand the system call path though. `map_lookup_elem` in `kernel/bpf/syscall.c` calls `map_lookup_elem_sys_only` if that is set, otherwise calls `map_lookup_elem`. For `sock_map`, `map_lookup_elem_sys_only` is set to `sock_map_lookup_sys`. Thus, the syscall `bpf(BPF_MAP_LOOKUP_ELEM)` will call `sock_map_lookup_sys`, not `sock_map_lookup`. However, the helper `bpf_map_lookup_elem` will call `sock_map_lookup`. The verifier replaces the helper call with a direct call to `map->ops->map_lookup_elem`, which is `sock_map_lookup`. This means the modified code *is* reachable and therefore *fuzzable* from BPF programs. Okay, this seems like a concrete and targetable area. I feel confident in assessing it as an important spot for fuzzing. |
| 56/2 | 2026/08/13 13:56 | tool | set-results |
0mArgs:{
"EnableConfigs": [
"BPF_SYSCALL",
"NET"
],
"FocusSymbols": [
"bpf_sk_lookup_tcp",
"bpf_sk_lookup_udp",
"bpf_tc_sk_lookup_tcp",
"bpf_tc_sk_lookup_udp",
"bpf_xdp_sk_lookup_udp",
"bpf_xdp_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_udp",
"sock_map_lookup",
"sock_hash_lookup"
],
"Reasoning": "The patch modifies BPF socket lookup helpers and BPF sockmap/sockhash map lookup operations. The changes refactor socket reference counting and are reachable from BPF programs and BPF syscalls.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": [
"BPF_SYSCALL",
"NET"
],
"FocusSymbols": [
"bpf_sk_lookup_tcp",
"bpf_sk_lookup_udp",
"bpf_tc_sk_lookup_tcp",
"bpf_tc_sk_lookup_udp",
"bpf_xdp_sk_lookup_udp",
"bpf_xdp_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_tcp",
"bpf_sock_addr_sk_lookup_udp",
"sock_map_lookup",
"sock_hash_lookup"
],
"Reasoning": "The patch modifies BPF socket lookup helpers and BPF sockmap/sockhash map lookup operations. The changes refactor socket reference counting and are reachable from BPF programs and BPF syscalls.",
"WorthFuzzing": true
} |
| 57/1 | 2026/08/13 13:56 | action | If |
0mArgs:{
"WorthFuzzing": true
}Results: null |
| 58/2 | 2026/08/13 13:56 | agent | kmsan-evaluator |
0mModel:best-expensive Args: null Results: {
"KMSANReasoning": "The patch refactors socket lookup logic in `net/core/filter.c` by extracting `bpf_sk_lookup_full_sk` and modifies socket reference counting in `net/core/sock_map.c` by replacing `refcount_inc_not_zero` with `sock_hold`. These changes are related to object lifetime, reference counting, and potential use-after-free issues. They do not introduce new allocations, modify bounds checking, or expose kernel memory to user space. Any bugs resulting from these changes (such as use-after-free or double free) would be caught by KASAN or standard refcount checking. Therefore, KMSAN is not applicable.",
"NeedsKMSAN": false
}Instruction: 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.
Prompt: For your convenience, here is the diff of the changes:
commit 871892a769cca4c55eab694966a3fe523be6318f
Author: syz-cluster <triage@syzkaller.com>
Date: Thu Aug 13 13:52:25 2026 +0000
syz-cluster: applied patch under review
diff --git a/net/core/filter.c b/net/core/filter.c
index 3423734124a5b..031fb2aad792a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7167,6 +7167,28 @@ __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
return sk;
}
+static struct sock *
+bpf_sk_lookup_full_sk(struct sock *sk)
+{
+ struct sock *sk2 = sk_to_full_sk(sk);
+
+ /*
+ * sk_to_full_sk() may return sk->rsk_listener, make sure the original
+ * sk sock refcnt is decremented to prevent a request_sock leak.
+ */
+ if (sk2 != sk) {
+ sock_gen_put(sk);
+ /* Ensure there is no need to bump sk2 refcnt. */
+ if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) {
+ WARN_ONCE(1, "Found non-RCU, unreferenced socket!");
+ return NULL;
+ }
+ sk = sk2;
+ }
+
+ return sk;
+}
+
static struct sock *
__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
@@ -7176,22 +7198,8 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
ifindex, proto, netns_id, flags,
sdif);
- if (sk) {
- struct sock *sk2 = sk_to_full_sk(sk);
-
- /* sk_to_full_sk() may return (sk)->rsk_listener, so make sure the original sk
- * sock refcnt is decremented to prevent a request_sock leak.
- */
- if (sk2 != sk) {
- sock_gen_put(sk);
- /* Ensure there is no need to bump sk2 refcnt */
- if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) {
- WARN_ONCE(1, "Found non-RCU, unreferenced socket!");
- return NULL;
- }
- sk = sk2;
- }
- }
+ if (sk)
+ sk = bpf_sk_lookup_full_sk(sk);
return sk;
}
@@ -7222,22 +7230,8 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct sock *sk = bpf_skc_lookup(skb, tuple, len, proto, netns_id,
flags);
- if (sk) {
- struct sock *sk2 = sk_to_full_sk(sk);
-
- /* sk_to_full_sk() may return (sk)->rsk_listener, so make sure the original sk
- * sock refcnt is decremented to prevent a request_sock leak.
- */
- if (sk2 != sk) {
- sock_gen_put(sk);
- /* Ensure there is no need to bump sk2 refcnt */
- if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) {
- WARN_ONCE(1, "Found non-RCU, unreferenced socket!");
- return NULL;
- }
- sk = sk2;
- }
- }
+ if (sk)
+ sk = bpf_sk_lookup_full_sk(sk);
return sk;
}
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 9efbd8ca7db83..ca49bc7f8687c 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -392,8 +392,8 @@ static void *sock_map_lookup(struct bpf_map *map, void *key)
sk = __sock_map_lookup_elem(map, *(u32 *)key);
if (!sk)
return NULL;
- if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
- return NULL;
+ if (sk_is_refcounted(sk))
+ sock_hold(sk);
return sk;
}
@@ -1218,8 +1218,8 @@ static void *sock_hash_lookup(struct bpf_map *map, void *key)
sk = __sock_hash_lookup_elem(map, key);
if (!sk)
return NULL;
- if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
- return NULL;
+ if (sk_is_refcounted(sk))
+ sock_hold(sk);
return sk;
}
|
| 59/3 | 2026/08/13 13:56 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 3176 output: 170 thoughts: 660 Thoughts: **KMSAN Assessment: Refactoring and Refcount Change in Socket Lookup** Okay, let me think this through. This patch touches `net/core/filter.c` and `net/core/sock_map.c`. In `filter.c`, it looks like a simple code refactoring; they're extracting `bpf_sk_lookup_full_sk` from `__bpf_sk_lookup` and `bpf_sk_lookup`. Nothing to see there really, just cleaning things up. Now, `sock_map.c` is where it gets interesting. They're changing the reference counting logic in `sock_map_lookup` and `sock_hash_lookup`. They've swapped out `refcount_inc_not_zero(&sk->sk_refcnt)` for `sock_hold(sk)`. That's a definite shift. `sock_hold` unconditionally increments the refcount, whereas the original check ensures the refcount isn't already zero. This screams refcount-related bug fix or change – likely a use-after-free or double-free mitigation. This is definitely KASAN/refcount-related, not KMSAN. Hold on, I need to check the prompt's criteria: does this introduce new structures to userspace, depend on uninitialized variables, allocate complex data structures, or mess with bounds checks leading to uninitialized byte access? Nope, none of those apply here. It's a refactoring and a refcount change. KMSAN is about uninitialized memory, which this isn't. Let me just quickly confirm that the `sock_hold` function really does increment the refcount unconditionally. Yep, it's just `refcount_inc(&sk->sk_refcnt)`. If the refcount was previously zero, then `sock_hold` will increment it from zero to one. This could lead to use-after-free or double free. It is absolutely KASAN/refcount territory. Okay, let me put this together into a clear justification: The patch refactors socket lookup code in `net/core/filter.c`, extracting `bpf_sk_lookup_full_sk`, and modifies socket reference counting in `net/core/sock_map.c`, replacing `refcount_inc_not_zero` with `sock_hold`. These changes relate to object lifetimes, reference counting, and the potential for use-after-free problems. They do not introduce new memory allocations, alter bounds checking, or expose kernel memory to user space. Any bugs resulting from these changes (such as use-after-free or double free) will be detected by KASAN or standard refcount debugging techniques. Therefore, KMSAN is not applicable. I'm setting `NeedsKMSAN=false`. |
| 60/3 | 2026/08/13 13:56 | tool | set-results |
0mArgs:{
"KMSANReasoning": "The patch refactors socket lookup logic in `net/core/filter.c` by extracting `bpf_sk_lookup_full_sk` and modifies socket reference counting in `net/core/sock_map.c` by replacing `refcount_inc_not_zero` with `sock_hold`. These changes are related to object lifetime, reference counting, and potential use-after-free issues. They do not introduce new allocations, modify bounds checking, or expose kernel memory to user space. Any bugs resulting from these changes (such as use-after-free or double free) would be caught by KASAN or standard refcount checking. Therefore, KMSAN is not applicable.",
"NeedsKMSAN": false
}Results: {
"KMSANReasoning": "The patch refactors socket lookup logic in `net/core/filter.c` by extracting `bpf_sk_lookup_full_sk` and modifies socket reference counting in `net/core/sock_map.c` by replacing `refcount_inc_not_zero` with `sock_hold`. These changes are related to object lifetime, reference counting, and potential use-after-free issues. They do not introduce new allocations, modify bounds checking, or expose kernel memory to user space. Any bugs resulting from these changes (such as use-after-free or double free) would be caught by KASAN or standard refcount checking. Therefore, KMSAN is not applicable.",
"NeedsKMSAN": false
} |
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