AI Trajectory

null

{
  "EnableConfigs": [
    "RDS",
    "RDS_RDMA",
    "RDS_TCP"
  ],
  "FocusSymbols": [
    "__rds_put_mr_final",
    "__rds_rdma_map",
    "rds_rdma_free_op",
    "rds_atomic_free_op",
    "rds_cmsg_rdma_args",
    "rds_send_xmit"
  ],
  "Reasoning": "The patch fixes a socket refcount leak in RDS RDMA operations by holding a socket reference in `__rds_rdma_map` and `rds_cmsg_rdma_args` and releasing it in `__rds_put_mr_final`. It also modifies `rds_rdma_free_op` and `rds_atomic_free_op` to use non-sleeping page unpinning functions since they can be called from tasklet context. Finally, it fixes a message refcount leak in `rds_send_xmit`. These are functional changes in the core RDS and RDMA logic that should be fuzzed.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit c9df6c1333fb1fa0884883d22aef69c43354cfcb\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Sat Jul 11 21:48:56 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/net/rds/rdma.c b/net/rds/rdma.c\nindex 61fb6e45281bf1..fe221968f3fe73 100644\n--- a/net/rds/rdma.c\n+++ b/net/rds/rdma.c\n@@ -117,6 +117,7 @@ void __rds_put_mr_final(struct kref *kref)\n \tstruct rds_mr *mr = container_of(kref, struct rds_mr, r_kref);\n \n \trds_destroy_mr(mr);\n+\tsock_put(rds_rs_to_sk(mr-\u003er_sock));\n \tkfree(mr);\n }\n \n@@ -243,7 +244,11 @@ static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args,\n \tkref_init(\u0026mr-\u003er_kref);\n \tRB_CLEAR_NODE(\u0026mr-\u003er_rb_node);\n \tmr-\u003er_trans = rs-\u003ers_transport;\n+\t/* The MR can outlive its socket: a socket reference is held\n+\t * until the final kref is dropped in __rds_put_mr_final().\n+\t */\n \tmr-\u003er_sock = rs;\n+\tsock_hold(rds_rs_to_sk(rs));\n \n \tif (args-\u003eflags \u0026 RDS_RDMA_USE_ONCE)\n \t\tmr-\u003er_use_once = 1;\n@@ -495,9 +500,13 @@ void rds_rdma_free_op(struct rm_rdma_op *ro)\n \n \t\t\t/* Mark page dirty if it was possibly modified, which\n \t\t\t * is the case for a RDMA_READ which copies from remote\n-\t\t\t * to local memory\n+\t\t\t * to local memory.  This can be called from the IB\n+\t\t\t * send completion tasklet, so the sleeping _lock\n+\t\t\t * variant must not be used here.\n \t\t\t */\n-\t\t\tunpin_user_pages_dirty_lock(\u0026page, 1, !ro-\u003eop_write);\n+\t\t\tif (!ro-\u003eop_write)\n+\t\t\t\tset_page_dirty(page);\n+\t\t\tunpin_user_page(page);\n \t\t}\n \t}\n \n@@ -513,8 +522,12 @@ void rds_atomic_free_op(struct rm_atomic_op *ao)\n \n \t/* Mark page dirty if it was possibly modified, which\n \t * is the case for a RDMA_READ which copies from remote\n-\t * to local memory */\n-\tunpin_user_pages_dirty_lock(\u0026page, 1, true);\n+\t * to local memory.  This can be called from the IB send\n+\t * completion tasklet, so the sleeping _lock variant must\n+\t * not be used here.\n+\t */\n+\tset_page_dirty(page);\n+\tunpin_user_page(page);\n \n \tkfree(ao-\u003eop_notifier);\n \tao-\u003eop_notifier = NULL;\n@@ -747,6 +760,10 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\n \t\t\t}\n \t\t\trdsdebug(\"Need odp; local_odp_mr %p trans_private %p\\n\",\n \t\t\t\t local_odp_mr, local_odp_mr-\u003er_trans_private);\n+\t\t\t/* From here on the MR is torn down through\n+\t\t\t * __rds_put_mr_final(), which drops this reference.\n+\t\t\t */\n+\t\t\tsock_hold(rds_rs_to_sk(rs));\n \t\t\top-\u003eop_odp_mr = local_odp_mr;\n \t\t\top-\u003eop_odp_addr = iov-\u003eaddr;\n \t\t}\ndiff --git a/net/rds/send.c b/net/rds/send.c\nindex 68be1bf0e0adf9..ab3a8366c53bd9 100644\n--- a/net/rds/send.c\n+++ b/net/rds/send.c\n@@ -339,9 +339,17 @@ int rds_send_xmit(struct rds_conn_path *cp)\n \t\t\t    (rm-\u003erdma.op_active \u0026\u0026\n \t\t\t    test_bit(RDS_MSG_RETRANSMITTED, \u0026rm-\u003em_flags))) {\n \t\t\t\tspin_lock_irqsave(\u0026cp-\u003ecp_lock, flags);\n-\t\t\t\tif (test_and_clear_bit(RDS_MSG_ON_CONN, \u0026rm-\u003em_flags))\n+\t\t\t\tif (test_and_clear_bit(RDS_MSG_ON_CONN, \u0026rm-\u003em_flags)) {\n+\t\t\t\t\t/* our ref is put after the batch */\n \t\t\t\t\tlist_move(\u0026rm-\u003em_conn_item, \u0026to_be_dropped);\n-\t\t\t\tspin_unlock_irqrestore(\u0026cp-\u003ecp_lock, flags);\n+\t\t\t\t\tspin_unlock_irqrestore(\u0026cp-\u003ecp_lock, flags);\n+\t\t\t\t} else {\n+\t\t\t\t\t/* already off the conn list; drop\n+\t\t\t\t\t * the ref taken above ourselves\n+\t\t\t\t\t */\n+\t\t\t\t\tspin_unlock_irqrestore(\u0026cp-\u003ecp_lock, flags);\n+\t\t\t\t\trds_message_put(rm);\n+\t\t\t\t}\n \t\t\t\tcontinue;\n \t\t\t}\n \n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": [
    "RDS",
    "RDS_RDMA",
    "RDS_TCP"
  ],
  "FocusSymbols": [
    "__rds_put_mr_final",
    "__rds_rdma_map",
    "rds_rdma_free_op",
    "rds_atomic_free_op",
    "rds_cmsg_rdma_args",
    "rds_send_xmit"
  ],
  "Reasoning": "The patch fixes a socket refcount leak in RDS RDMA operations by holding a socket reference in `__rds_rdma_map` and `rds_cmsg_rdma_args` and releasing it in `__rds_put_mr_final`. It also modifies `rds_rdma_free_op` and `rds_atomic_free_op` to use non-sleeping page unpinning functions since they can be called from tasklet context. Finally, it fixes a message refcount leak in `rds_send_xmit`. These are functional changes in the core RDS and RDMA logic that should be fuzzed.",
  "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).

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.
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.
   Do not list too generic configs (we already have them enabled). Only list those that
   specifically cover the modified code. 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 c9df6c1333fb1fa0884883d22aef69c43354cfcb
Author: syz-cluster <triage@syzkaller.com>
Date:   Sat Jul 11 21:48:56 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 61fb6e45281bf1..fe221968f3fe73 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -117,6 +117,7 @@ void __rds_put_mr_final(struct kref *kref)
 	struct rds_mr *mr = container_of(kref, struct rds_mr, r_kref);
 
 	rds_destroy_mr(mr);
+	sock_put(rds_rs_to_sk(mr->r_sock));
 	kfree(mr);
 }
 
@@ -243,7 +244,11 @@ static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args,
 	kref_init(&mr->r_kref);
 	RB_CLEAR_NODE(&mr->r_rb_node);
 	mr->r_trans = rs->rs_transport;
+	/* The MR can outlive its socket: a socket reference is held
+	 * until the final kref is dropped in __rds_put_mr_final().
+	 */
 	mr->r_sock = rs;
+	sock_hold(rds_rs_to_sk(rs));
 
 	if (args->flags & RDS_RDMA_USE_ONCE)
 		mr->r_use_once = 1;
@@ -495,9 +500,13 @@ void rds_rdma_free_op(struct rm_rdma_op *ro)
 
 			/* Mark page dirty if it was possibly modified, which
 			 * is the case for a RDMA_READ which copies from remote
-			 * to local memory
+			 * to local memory.  This can be called from the IB
+			 * send completion tasklet, so the sleeping _lock
+			 * variant must not be used here.
 			 */
-			unpin_user_pages_dirty_lock(&page, 1, !ro->op_write);
+			if (!ro->op_write)
+				set_page_dirty(page);
+			unpin_user_page(page);
 		}
 	}
 
@@ -513,8 +522,12 @@ void rds_atomic_free_op(struct rm_atomic_op *ao)
 
 	/* Mark page dirty if it was possibly modified, which
 	 * is the case for a RDMA_READ which copies from remote
-	 * to local memory */
-	unpin_user_pages_dirty_lock(&page, 1, true);
+	 * to local memory.  This can be called from the IB send
+	 * completion tasklet, so the sleeping _lock variant must
+	 * not be used here.
+	 */
+	set_page_dirty(page);
+	unpin_user_page(page);
 
 	kfree(ao->op_notifier);
 	ao->op_notifier = NULL;
@@ -747,6 +760,10 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 			}
 			rdsdebug("Need odp; local_odp_mr %p trans_private %p\n",
 				 local_odp_mr, local_odp_mr->r_trans_private);
+			/* From here on the MR is torn down through
+			 * __rds_put_mr_final(), which drops this reference.
+			 */
+			sock_hold(rds_rs_to_sk(rs));
 			op->op_odp_mr = local_odp_mr;
 			op->op_odp_addr = iov->addr;
 		}
diff --git a/net/rds/send.c b/net/rds/send.c
index 68be1bf0e0adf9..ab3a8366c53bd9 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -339,9 +339,17 @@ int rds_send_xmit(struct rds_conn_path *cp)
 			    (rm->rdma.op_active &&
 			    test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))) {
 				spin_lock_irqsave(&cp->cp_lock, flags);
-				if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
+				if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
+					/* our ref is put after the batch */
 					list_move(&rm->m_conn_item, &to_be_dropped);
-				spin_unlock_irqrestore(&cp->cp_lock, flags);
+					spin_unlock_irqrestore(&cp->cp_lock, flags);
+				} else {
+					/* already off the conn list; drop
+					 * the ref taken above ourselves
+					 */
+					spin_unlock_irqrestore(&cp->cp_lock, flags);
+					rds_message_put(rm);
+				}
 				continue;
 			}
 

gemini-3.1-pro-preview

null

null

							input: 2954
							output: 28
							thoughts: 214
						

**RDS Patch Analysis and Fuzzing Strategy**

Okay, so I've got a patch here that's poking around in the RDS subsystem – specifically `net/rds/rdma.c` and `net/rds/send.c`. My initial read suggests some important refactoring around socket lifecycle management related to RDMA operations. They've added socket reference counting using `sock_hold` and `sock_put` within `rds_mr` and `rds_cmsg_rdma_args`, which is smart. Ensures the socket outlives the memory region, which is a common source of subtle memory corruption bugs. The other change with replacing `unpin_user_pages_dirty_lock` with `set_page_dirty` and `unpin_user_page` in `rds_rdma_free_op` and `rds_atomic_free_op` because it's in a tasklet context is a good move too – avoids potential locking issues. Finally, fixing that refcount leak in `rds_send_xmit` when messages are already off the connection list? Definitely a win!

Functionally, this is a pretty significant change to RDS's behaviour. It alters how it handles resources, especially memory management and socket lifespan, in RDMA operations. I would consider this a high-priority candidate for fuzzing, given that it touches memory management and network interactions; those are always risky areas.

Now, let's figure out how to build this with fuzzing enabled. I'll need to figure out the relevant configuration options. Time to search the kernel config for `CONFIG_RDS` or anything related. Let's see what we can find.

{
  "Expression": "config RDS",
  "PathPrefix": "net/rds/Kconfig"
}

{
  "Output": "net/rds/Kconfig-2-\nnet/rds/Kconfig:3:config RDS\nnet/rds/Kconfig-4-\ttristate \"The Reliable Datagram Sockets Protocol\"\n--\nnet/rds/Kconfig-9-\nnet/rds/Kconfig:10:config RDS_RDMA\nnet/rds/Kconfig-11-\ttristate \"RDS over Infiniband\"\n--\nnet/rds/Kconfig-16-\nnet/rds/Kconfig:17:config RDS_TCP\nnet/rds/Kconfig-18-\ttristate \"RDS over TCP\"\n--\nnet/rds/Kconfig-24-\nnet/rds/Kconfig:25:config RDS_DEBUG\nnet/rds/Kconfig-26-\tbool \"RDS debugging messages\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 3751
							output: 29
							thoughts: 54
						

Okay, here's my take on those thoughts, framed as my own mental processing:

**Examining the RDS/RDMA Configuration**

Right, so I'm focusing on `RDS` as the core configuration element here. I immediately have a hunch that `RDS_RDMA` is going to be important – probably *crucial* – for the proper handling of `net/rds/rdma.c`. It's a classic scenario; I need to verify whether that RDMA implementation is compiled into the module conditionally. My next logical step is to dive into the `net/rds/Makefile` and see if `rdma.c` has any build directives around it. That'll tell me if `RDS_RDMA` actually controls whether that RDMA functionality is included. I need that build process information as part of my overview.

{
  "Expression": "rdma\\.o",
  "PathPrefix": "net/rds/Makefile"
}

{
  "Output": "net/rds/Makefile=3=rds-y :=\taf_rds.o bind.o cong.o connection.o info.o message.o   \\\nnet/rds/Makefile-4-\t\t\trecv.o send.o stats.o sysctl.o threads.o transport.o \\\nnet/rds/Makefile:5:\t\t\tloop.o page.o rdma.o\nnet/rds/Makefile-6-\nnet/rds/Makefile:7:obj-$(CONFIG_RDS_RDMA) += rds_rdma.o\nnet/rds/Makefile-8-rds_rdma-y :=\trdma_transport.o \\\nnet/rds/Makefile-9-\t\t\tib.o ib_cm.o ib_recv.o ib_ring.o ib_send.o ib_stats.o \\\nnet/rds/Makefile:10:\t\t\tib_sysctl.o ib_rdma.o ib_frmr.o\nnet/rds/Makefile-11-\n"
}

gemini-3.1-pro-preview

null

null

							input: 4247
							output: 33
							thoughts: 388
						

**Analyzing RDS/RDMA Configuration Dependencies**

Okay, so I'm looking at this kernel module stuff. It seems `rdma.o` is baked in with `rds-y`, and therefore is built when `CONFIG_RDS` is enabled. Similarly, `rds_rdma.o` gets compiled only when `CONFIG_RDS_RDMA` is set. The file that's been modified, `net/rds/rdma.c`, relates directly to `rdma.o`, so intuitively, `CONFIG_RDS` should be enough to incorporate those changes. But wait a sec... `net/rds/rdma.c` *handles* RDMA operations for RDS. I need to make sure `RDS_RDMA` isn't required to actually *use* the RDMA bits within that file, so let me delve deeper.

Let's see, the changes are centered around these functions: `__rds_put_mr_final`, `__rds_rdma_map`, `rds_rdma_free_op`, `rds_atomic_free_op`, `rds_cmsg_rdma_args`, and `rds_send_xmit`. Hang on... `rds_send_xmit` is actually in `net/rds/send.c`, which is also included in the `rds-y` module.

Alright, time to focus. I need to figure out which of these functions are the key ones that demand further scrutiny.

So, here's my list of modified functions, again:
- `__rds_put_mr_final`
- `__rds_rdma_map`
- `rds_rdma_free_op`
- `rds_atomic_free_op`
- `rds_cmsg_rdma_args`
- `rds_send_xmit`

`rds_send_xmit` is almost certainly a hot path – that's the message transmission function, so that's definitely a candidate. `__rds_rdma_map` and `rds_cmsg_rdma_args` look promising too, they are probably involved in setting up the RDMA mappings. Plus, `rds_rdma_free_op` and `rds_atomic_free_op` are very likely involved with memory management related to the RDMA transfers, which is important for performance.

I'm going to start by double-checking the code in `rds_cmsg_rdma_args` and `__rds_rdma_map` to see what's what.

{
  "Expression": "rds_cmsg_rdma_args",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/rdma.c=566=int rds_rdma_extra_size(struct rds_rdma_args *args,\n--\nnet/rds/rdma.c-617- */\nnet/rds/rdma.c:618:int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rdma.c-619-\t\t       struct cmsghdr *cmsg,\n--\nnet/rds/rds.h=966=int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rds.h-967-\t\t\t  struct cmsghdr *cmsg);\nnet/rds/rds.h:968:int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rds.h-969-\t\t\t  struct cmsghdr *cmsg,\n--\nnet/rds/send.c=1053=static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,\n--\nnet/rds/send.c-1073-\t\t\t\treturn -ENOMEM;\nnet/rds/send.c:1074:\t\t\tret = rds_cmsg_rdma_args(rs, rm, cmsg, \u0026vct-\u003evec[ind]);\nnet/rds/send.c-1075-\t\t\tind++;\n"
}

gemini-3.1-pro-preview

null

null

							input: 5603
							output: 31
							thoughts: 67
						

Here's my analysis of the provided information, as if these were my internal thoughts:

**Fuzzing Target Identification: A Control Message Bonanza!**

Okay, so we're looking at RDMA and message handling. Excellent. My initial thought is that `rds_cmsg_rdma_args` is a prime candidate for fuzzing. It's triggered during send-side control message parsing – which screams potential vulnerability points due to the complexity and variability of user-supplied data. This is precisely the kind of function that loves to reveal subtle flaws when fed malformed input. This is where I would start my fuzzing campaign.

Now, let's dig a bit deeper. I see `__rds_rdma_map` gets called from `rds_get_mr`. This is interesting. `rds_get_mr` sounds like it handles memory regions, probably related to the RDMA setup. The crucial question now is where `rds_get_mr` is called from. Is this an ioctl call, a setsockopt, or perhaps something else entirely? Knowing this calling context will be vital for understanding the attack surface and how to exploit potential flaws. It will guide me on where to place the fuzzing harness. That's the next thing to investigate.

{
  "Expression": "__rds_rdma_map",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/rdma.c=155=static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,\n--\nnet/rds/rdma.c-172-\nnet/rds/rdma.c:173:static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args,\nnet/rds/rdma.c-174-\t\t\t  u64 *cookie_ret, struct rds_mr **mr_ret,\n--\nnet/rds/rdma.c=360=int rds_get_mr(struct rds_sock *rs, sockptr_t optval, int optlen)\n--\nnet/rds/rdma.c-369-\nnet/rds/rdma.c:370:\treturn __rds_rdma_map(rs, \u0026args, NULL, NULL, NULL);\nnet/rds/rdma.c-371-}\n--\nnet/rds/rdma.c=373=int rds_get_mr_for_dest(struct rds_sock *rs, sockptr_t optval, int optlen)\n--\nnet/rds/rdma.c-393-\nnet/rds/rdma.c:394:\treturn __rds_rdma_map(rs, \u0026new_args, NULL, NULL, NULL);\nnet/rds/rdma.c-395-}\n--\nnet/rds/rdma.c=864=int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,\n--\nnet/rds/rdma.c-870-\nnet/rds/rdma.c:871:\treturn __rds_rdma_map(rs, CMSG_DATA(cmsg), \u0026rm-\u003em_rdma_cookie,\nnet/rds/rdma.c-872-\t\t\t      \u0026rm-\u003erdma.op_rdma_mr, rm-\u003em_conn_path);\n"
}

gemini-3.1-pro-preview

null

null

							input: 6473
							output: 32
							thoughts: 111
						

Okay, let's break this down.

**Focusing on RDMA Mapping and Free Operations**

My initial thought is that `__rds_rdma_map` is the key function to dissect here. I see it's called from `rds_get_mr`, `rds_get_mr_for_dest`, and `rds_cmsg_rdma_map`. Given my understanding of the system, that means these are potentially user-accessible via `setsockopt` and `sendmsg`. Since those syscalls are the interface to userspace for these functions, `__rds_rdma_map` and its associated structure `rds_cmsg_rdma_args` are clearly the focal points of any investigation into this RDMA functionality. I need to understand them fully.

Next, I should look closely at `rds_rdma_free_op` and `rds_atomic_free_op`. The mapping and unmapping/freeing operations are always the critical points to analyze for resource management issues, especially in RDMA contexts where memory is being pinned.

{
  "Expression": "rds_rdma_free_op",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/message.c=132=static void rds_message_purge(struct rds_message *rm)\n--\nnet/rds/message.c-174-\tif (rm-\u003erdma.op_active)\nnet/rds/message.c:175:\t\trds_rdma_free_op(\u0026rm-\u003erdma);\nnet/rds/message.c-176-\tif (rm-\u003erdma.op_rdma_mr)\n--\nnet/rds/rdma.c=446=void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force)\n--\nnet/rds/rdma.c-490-\nnet/rds/rdma.c:491:void rds_rdma_free_op(struct rm_rdma_op *ro)\nnet/rds/rdma.c-492-{\n--\nnet/rds/rdma.c=618=int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\n--\nnet/rds/rdma.c-809-\tif (ret)\nnet/rds/rdma.c:810:\t\trds_rdma_free_op(op);\nnet/rds/rdma.c-811-\telse\n--\nnet/rds/rds.h=971=int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rds.h-972-\t\t\t  struct cmsghdr *cmsg);\nnet/rds/rds.h:973:void rds_rdma_free_op(struct rm_rdma_op *ro);\nnet/rds/rds.h-974-void rds_atomic_free_op(struct rm_atomic_op *ao);\n"
}

gemini-3.1-pro-preview

null

null

							input: 6482
							output: 31
							thoughts: 0
						

{
  "Expression": "rds_atomic_free_op",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/message.c=132=static void rds_message_purge(struct rds_message *rm)\n--\nnet/rds/message.c-179-\tif (rm-\u003eatomic.op_active)\nnet/rds/message.c:180:\t\trds_atomic_free_op(\u0026rm-\u003eatomic);\nnet/rds/message.c-181-\tif (rm-\u003eatomic.op_rdma_mr)\n--\nnet/rds/rdma.c=491=void rds_rdma_free_op(struct rm_rdma_op *ro)\n--\nnet/rds/rdma.c-518-\nnet/rds/rdma.c:519:void rds_atomic_free_op(struct rm_atomic_op *ao)\nnet/rds/rdma.c-520-{\n--\nnet/rds/rds.h=973=void rds_rdma_free_op(struct rm_rdma_op *ro);\nnet/rds/rds.h:974:void rds_atomic_free_op(struct rm_atomic_op *ao);\nnet/rds/rds.h-975-void rds_rdma_send_complete(struct rds_message *rm, int wc_status);\n"
}

gemini-3.1-pro-preview

null

null

							input: 7673
							output: 30
							thoughts: 50
						

Okay, here's my take on those code paths.

**Examining Potential Cleanup Candidates in RDS**

Right, so I'm thinking about where we might be able to improve message handling. Looking at potential optimization opportunities, I'm focusing on areas where we're releasing resources or handling errors. `rds_rdma_free_op` and `rds_atomic_free_op` immediately spring to mind. Seems like they're called during message purging or in error scenarios, which suggests they could be worthwhile targets for refinement. Need to examine what their roles are.

Now, let's turn our attention to `rds_send_xmit` to see if there are any opportunities in the send path, since this is a critical spot for performance.

{
  "Expression": "rds_send_xmit",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/cong.c=217=void rds_cong_queue_updates(struct rds_cong_map *map)\n--\nnet/rds/cong.c-230-\t\t\trds_stats_inc(s_cong_update_queued);\nnet/rds/cong.c:231:\t\t\t/* We cannot inline the call to rds_send_xmit() here\nnet/rds/cong.c-232-\t\t\t * for two reasons (both pertaining to a TCP transport):\n--\nnet/rds/ib_cm.c=282=static void rds_ib_tasklet_fn_send(unsigned long data)\n--\nnet/rds/ib_cm.c-299-\t    test_bit(0, \u0026conn-\u003ec_map_queued)))\nnet/rds/ib_cm.c:300:\t\trds_send_xmit(\u0026ic-\u003econn-\u003ec_path[0]);\nnet/rds/ib_cm.c-301-}\n--\nnet/rds/ib_send.c=245=void rds_ib_send_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc)\n--\nnet/rds/ib_send.c-335- *\nnet/rds/ib_send.c:336: * The RDS send code is essentially single-threaded; rds_send_xmit\nnet/rds/ib_send.c-337- * sets RDS_IN_XMIT to ensure exclusive access to the send ring.\n--\nnet/rds/loop.c=231=void rds_loop_net_exit(void)\n--\nnet/rds/loop.c-237- * This is missing .xmit_* because loop doesn't go through generic\nnet/rds/loop.c:238: * rds_send_xmit() and doesn't call rds_recv_incoming().  .listen_stop and\nnet/rds/loop.c-239- * .laddr_check are missing because transport.c doesn't iterate over\n--\nnet/rds/rds.h=529=struct rds_transport {\n--\nnet/rds/rds.h-569-\t/*\nnet/rds/rds.h:570:\t * .xmit is called by rds_send_xmit() to tell the transport to send\nnet/rds/rds.h-571-\t * part of a message.  The caller serializes on the send_sem so this\n--\nnet/rds/rds.h=946=void rds_send_path_reset(struct rds_conn_path *conn);\nnet/rds/rds.h:947:int rds_send_xmit(struct rds_conn_path *cp);\nnet/rds/rds.h-948-struct sockaddr_in;\n--\nnet/rds/send.c-44-\nnet/rds/send.c:45:/* When transmitting messages in rds_send_xmit, we need to emerge from\nnet/rds/send.c-46- * time to time and briefly release the CPU. Otherwise the softlock watchdog\n--\nnet/rds/send.c=59=static void rds_send_remove_from_sock(struct list_head *messages, int status);\n--\nnet/rds/send.c-62- * Reset the send state.  Callers must ensure that this doesn't race with\nnet/rds/send.c:63: * rds_send_xmit().\nnet/rds/send.c-64- */\n--\nnet/rds/send.c=128=static bool rds_mprds_cp0_catchup(struct rds_connection *conn)\n--\nnet/rds/send.c-186- */\nnet/rds/send.c:187:int rds_send_xmit(struct rds_conn_path *cp)\nnet/rds/send.c-188-{\n--\nnet/rds/send.c-537-}\nnet/rds/send.c:538:EXPORT_SYMBOL_GPL(rds_send_xmit);\nnet/rds/send.c-539-\n--\nnet/rds/send.c=672=static void rds_send_remove_from_sock(struct list_head *messages, int status)\n--\nnet/rds/send.c-747- * messages up to, and including, the given sequence number.  Messages are\nnet/rds/send.c:748: * moved to the retrans queue when rds_send_xmit picks them off the send\nnet/rds/send.c-749- * queue. This means that in the TCP case, the message may not have been\n--\nnet/rds/send.c=1137=int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)\n--\nnet/rds/send.c-1434-\nnet/rds/send.c:1435:\tret = rds_send_xmit(cpath);\nnet/rds/send.c-1436-\tif (ret == -ENOMEM || ret == -EAGAIN) {\n--\nnet/rds/tcp.c=126=void rds_tcp_reset_callbacks(struct socket *sock,\n--\nnet/rds/tcp.c-140-\t * cp_state to something other than RDS_CONN_UP, and then\nnet/rds/tcp.c:141:\t * waiting for any existing threads in rds_send_xmit to\nnet/rds/tcp.c-142-\t * complete release_in_xmit(). (Subsequent threads entering\nnet/rds/tcp.c:143:\t * rds_send_xmit() will bail on !rds_conn_up().\nnet/rds/tcp.c-144-\t *\n--\nnet/rds/threads.c=191=void rds_send_worker(struct work_struct *work)\n--\nnet/rds/threads.c-199-\t\tclear_bit(RDS_LL_SEND_FULL, \u0026cp-\u003ecp_flags);\nnet/rds/threads.c:200:\t\tret = rds_send_xmit(cp);\nnet/rds/threads.c-201-\t\tcond_resched();\n"
}

gemini-3.1-pro-preview

null

null

							input: 8580
							output: 28
							thoughts: 0
						

{
  "Expression": "rds_sendmsg",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/af_rds.c=646=static const struct proto_ops rds_proto_ops = {\n--\nnet/rds/af_rds.c-660-\t.getsockopt_iter =\trds_getsockopt,\nnet/rds/af_rds.c:661:\t.sendmsg =\trds_sendmsg,\nnet/rds/af_rds.c-662-\t.recvmsg =\trds_recvmsg,\n--\nnet/rds/rds.h=618=struct rds_sock {\n--\nnet/rds/rds.h-640-\t/*\nnet/rds/rds.h:641:\t * rds_sendmsg caches the conn it used the last time around.\nnet/rds/rds.h-642-\t * This helps avoid costly lookups.\n--\nnet/rds/rds.h=939=void rds6_inc_info_copy(struct rds_incoming *inc,\n--\nnet/rds/rds.h-944-/* send.c */\nnet/rds/rds.h:945:int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len);\nnet/rds/rds.h-946-void rds_send_path_reset(struct rds_conn_path *conn);\n--\nnet/rds/recv.c=199=static void rds_recv_hs_exthdrs(struct rds_header *hdr,\n--\nnet/rds/recv.c-270- *\nnet/rds/recv.c:271: * 1. rds_sendmsg on first connect attempt sends the probe ping, with the\nnet/rds/recv.c-272- *    sender's npaths (s_npaths)\n--\nnet/rds/send.c=1114=static int rds_rdma_bytes(struct msghdr *msg, size_t *rdma_bytes)\n--\nnet/rds/send.c-1136-\nnet/rds/send.c:1137:int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)\nnet/rds/send.c-1138-{\n--\nnet/rds/send.c-1162-\nnet/rds/send.c:1163:\t/* expect 1 RDMA CMSG per rds_sendmsg. can still grow if more needed. */\nnet/rds/send.c-1164-\tvct.incr = 1;\n"
}

gemini-3.1-pro-preview

null

null

							input: 10134
							output: 30
							thoughts: 300
						

**My Analysis of the RDS Send Vulnerability**

Okay, so I'm looking at this patch and the core of the problem seems to be in `rds_send_xmit`. It's the central function handling message sending in RDS, called from both `rds_sendmsg` and `rds_send_worker`. That makes it a natural focal point for my analysis, although, because it is the primary send function, it might be a bit too broad to start.

However, the patch *specifically* targets an error condition within `rds_send_xmit` when RDMA operations are active – `rm->rdma.op_active` is true – and a message has been retransmitted, as flagged by `RDS_MSG_RETRANSMITTED`. This really narrows down the potential attack vector. That gives me a precise focus. I should be fuzzing `rds_sendmsg` and specifically targeting RDMA-related operations.

I'll definitely include `rds_send_xmit` in my focus symbols, but also want to include the supporting functions that might be involved in the error path. I should also include `__rds_rdma_map`, `rds_cmsg_rdma_args`, `rds_rdma_free_op`, and `rds_atomic_free_op`. These should be the key ingredients, especially in conjunction with the retransmission code path.

One thing I need to double check is that this is indeed specific to the RDMA path. The patch touches `net/rds/rdma.c`, and that's obviously suggestive. I know `rdma.c` is compiled under `CONFIG_RDS`, but I need to make sure that `CONFIG_RDS_RDMA` is needed, just to be sure. I'm going to quickly re-check `net/rds/Kconfig` to be sure.

{
  "Expression": "RDS_RDMA",
  "PathPrefix": "net/rds/Kconfig"
}

{
  "Output": "net/rds/Kconfig=3=config RDS\n--\nnet/rds/Kconfig-9-\nnet/rds/Kconfig:10:config RDS_RDMA\nnet/rds/Kconfig-11-\ttristate \"RDS over Infiniband\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 9750
							output: 29
							thoughts: 0
						

{
  "Expression": "RDS_RDMA",
  "PathPrefix": "net/rds/Makefile"
}

{
  "Output": "net/rds/Makefile=3=rds-y :=\taf_rds.o bind.o cong.o connection.o info.o message.o   \\\n--\nnet/rds/Makefile-6-\nnet/rds/Makefile:7:obj-$(CONFIG_RDS_RDMA) += rds_rdma.o\nnet/rds/Makefile-8-rds_rdma-y :=\trdma_transport.o \\\n"
}

gemini-3.1-pro-preview

null

null

							input: 11073
							output: 33
							thoughts: 73
						

**Investigating the RDS and RDMA Compilation Dependencies**

Okay, so I'm looking at `net/rds/rdma.c`. It's pretty clear that this code gets compiled when `CONFIG_RDS` is enabled. But, here's the real question: does simply having `CONFIG_RDS` give me RDMA functionality within RDS? Or, is `CONFIG_RDS_RDMA` a hard requirement for that specific RDMA integration?

I need to figure out if there's any pathway to `rds_cmsg_rdma_args` without `CONFIG_RDS_RDMA`. I need to trace the dependencies to understand if RDS RDMA can be used without explicitly enabling it, which would be an unexpected configuration. I need to be sure.

{
  "Expression": "rds_cmsg_rdma_args",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/rdma.c=566=int rds_rdma_extra_size(struct rds_rdma_args *args,\n--\nnet/rds/rdma.c-617- */\nnet/rds/rdma.c:618:int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rdma.c-619-\t\t       struct cmsghdr *cmsg,\n--\nnet/rds/rds.h=966=int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rds.h-967-\t\t\t  struct cmsghdr *cmsg);\nnet/rds/rds.h:968:int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\nnet/rds/rds.h-969-\t\t\t  struct cmsghdr *cmsg,\n--\nnet/rds/send.c=1053=static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,\n--\nnet/rds/send.c-1073-\t\t\t\treturn -ENOMEM;\nnet/rds/send.c:1074:\t\t\tret = rds_cmsg_rdma_args(rs, rm, cmsg, \u0026vct-\u003evec[ind]);\nnet/rds/send.c-1075-\t\t\tind++;\n"
}

gemini-3.1-pro-preview

null

null

							input: 11727
							output: 36
							thoughts: 105
						

**Analyzing the RDS RDMA Argument Handling**

Okay, so `rds_cmsg_rdma_args` is called from `rds_cmsg_send` within `net/rds/send.c`. That's straightforward; it's part of the Remote Direct Memory Access functionality within the Reliable Datagram Sockets (RDS) implementation, and it's built when `CONFIG_RDS` is enabled. Seems logical.

However, the key question now becomes: *does* `rds_cmsg_rdma_args` *require* an underlying RDMA transport to be functional, or will it simply execute, potentially failing later if no RDMA hardware is present? The presence of the function with the `CONFIG_RDS` dependency alone doesn't clarify its operational reliance on an RDMA-capable setup. This feels like an optimization that needs deeper probing. Therefore, I need to dive into the implementation of `rds_cmsg_rdma_args` itself. That's the only way to understand its actual behavior and conditional dependencies. Let's see what's actually going on in that function.

{
  "File": "net/rds/rdma.c",
  "FirstLine": 618,
  "LineCount": 50
}

{
  "Contents": " 618:\tint rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\n 619:\t\t\t       struct cmsghdr *cmsg,\n 620:\t\t\t       struct rds_iov_vector *vec)\n 621:\t{\n 622:\t\tstruct rds_rdma_args *args;\n 623:\t\tstruct rm_rdma_op *op = \u0026rm-\u003erdma;\n 624:\t\tint nr_pages;\n 625:\t\tunsigned int nr_bytes;\n 626:\t\tstruct page **pages = NULL;\n 627:\t\tstruct rds_iovec *iovs;\n 628:\t\tunsigned int i, j;\n 629:\t\tint ret = 0;\n 630:\t\tbool odp_supported = true;\n 631:\t\n 632:\t\tif (cmsg-\u003ecmsg_len \u003c CMSG_LEN(sizeof(struct rds_rdma_args))\n 633:\t\t    || rm-\u003erdma.op_active)\n 634:\t\t\treturn -EINVAL;\n 635:\t\n 636:\t\targs = CMSG_DATA(cmsg);\n 637:\t\n 638:\t\tif (ipv6_addr_any(\u0026rs-\u003ers_bound_addr)) {\n 639:\t\t\tret = -ENOTCONN; /* XXX not a great errno */\n 640:\t\t\tgoto out_ret;\n 641:\t\t}\n 642:\t\n 643:\t\tif (args-\u003enr_local \u003e UIO_MAXIOV) {\n 644:\t\t\tret = -EMSGSIZE;\n 645:\t\t\tgoto out_ret;\n 646:\t\t}\n 647:\t\n 648:\t\tif (vec-\u003elen != args-\u003enr_local) {\n 649:\t\t\tret = -EINVAL;\n 650:\t\t\tgoto out_ret;\n 651:\t\t}\n 652:\t\t/* odp-mr is not supported for multiple requests within one message */\n 653:\t\tif (args-\u003enr_local != 1)\n 654:\t\t\todp_supported = false;\n 655:\t\n 656:\t\tiovs = vec-\u003eiov;\n 657:\t\n 658:\t\tnr_pages = rds_rdma_pages(iovs, args-\u003enr_local);\n 659:\t\tif (nr_pages \u003c 0) {\n 660:\t\t\tret = -EINVAL;\n 661:\t\t\tgoto out_ret;\n 662:\t\t}\n 663:\t\n 664:\t\tpages = kzalloc_objs(struct page *, nr_pages);\n 665:\t\tif (!pages) {\n 666:\t\t\tret = -ENOMEM;\n 667:\t\t\tgoto out_ret;\n"
}

gemini-3.1-pro-preview

null

null

							input: 11483
							output: 36
							thoughts: 0
						

{
  "File": "net/rds/rdma.c",
  "FirstLine": 750,
  "LineCount": 50
}

{
  "Contents": " 750:\t\t\t\t\trs-\u003ers_transport-\u003eget_mr(\n 751:\t\t\t\t\t\tNULL, 0, rs, \u0026local_odp_mr-\u003er_key, NULL,\n 752:\t\t\t\t\t\tiov-\u003eaddr, iov-\u003ebytes, ODP_VIRTUAL);\n 753:\t\t\t\tif (IS_ERR(local_odp_mr-\u003er_trans_private)) {\n 754:\t\t\t\t\tret = PTR_ERR(local_odp_mr-\u003er_trans_private);\n 755:\t\t\t\t\trdsdebug(\"get_mr ret %d %p\\\"\", ret,\n 756:\t\t\t\t\t\t local_odp_mr-\u003er_trans_private);\n 757:\t\t\t\t\tkfree(local_odp_mr);\n 758:\t\t\t\t\tret = -EOPNOTSUPP;\n 759:\t\t\t\t\tgoto out_pages;\n 760:\t\t\t\t}\n 761:\t\t\t\trdsdebug(\"Need odp; local_odp_mr %p trans_private %p\\n\",\n 762:\t\t\t\t\t local_odp_mr, local_odp_mr-\u003er_trans_private);\n 763:\t\t\t\t/* From here on the MR is torn down through\n 764:\t\t\t\t * __rds_put_mr_final(), which drops this reference.\n 765:\t\t\t\t */\n 766:\t\t\t\tsock_hold(rds_rs_to_sk(rs));\n 767:\t\t\t\top-\u003eop_odp_mr = local_odp_mr;\n 768:\t\t\t\top-\u003eop_odp_addr = iov-\u003eaddr;\n 769:\t\t\t}\n 770:\t\n 771:\t\t\trdsdebug(\"RDS: nr_bytes %u nr %u iov-\u003ebytes %llu iov-\u003eaddr %llx\\n\",\n 772:\t\t\t\t nr_bytes, nr, iov-\u003ebytes, iov-\u003eaddr);\n 773:\t\n 774:\t\t\tnr_bytes += iov-\u003ebytes;\n 775:\t\n 776:\t\t\tfor (j = 0; j \u003c nr; j++) {\n 777:\t\t\t\tunsigned int offset = iov-\u003eaddr \u0026 ~PAGE_MASK;\n 778:\t\t\t\tstruct scatterlist *sg;\n 779:\t\n 780:\t\t\t\tsg = \u0026op-\u003eop_sg[op-\u003eop_nents + j];\n 781:\t\t\t\tsg_set_page(sg, pages[j],\n 782:\t\t\t\t\t\tmin_t(unsigned int, iov-\u003ebytes, PAGE_SIZE - offset),\n 783:\t\t\t\t\t\toffset);\n 784:\t\n 785:\t\t\t\tsg_dma_len(sg) = sg-\u003elength;\n 786:\t\t\t\trdsdebug(\"RDS: sg-\u003eoffset %x sg-\u003elen %x iov-\u003eaddr %llx iov-\u003ebytes %llu\\n\",\n 787:\t\t\t\t       sg-\u003eoffset, sg-\u003elength, iov-\u003eaddr, iov-\u003ebytes);\n 788:\t\n 789:\t\t\t\tiov-\u003eaddr += sg-\u003elength;\n 790:\t\t\t\tiov-\u003ebytes -= sg-\u003elength;\n 791:\t\t\t}\n 792:\t\n 793:\t\t\top-\u003eop_nents += nr;\n 794:\t\t}\n 795:\t\n 796:\t\tif (nr_bytes \u003e args-\u003eremote_vec.bytes) {\n 797:\t\t\trdsdebug(\"RDS nr_bytes %u remote_bytes %u do not match\\n\",\n 798:\t\t\t\t\tnr_bytes,\n 799:\t\t\t\t\t(unsigned int) args-\u003eremote_vec.bytes);\n"
}

gemini-3.1-pro-preview

null

null

							input: 13777
							output: 28
							thoughts: 135
						

**Analyzing the RDS RDMA Code Path**

Okay, so I'm looking at how `rds_cmsg_rdma_args` works and it appears to rely on `rs->rs_transport->get_mr`. My initial thought is that if there's no transport bound, this could fail pretty early on. However, the code *is* reachable, so that assumption is a bit shaky. I'm wondering if `CONFIG_RDS_RDMA` is actually *required* to trigger this specific section. Probably not, strictly speaking, to just *reach* the code. However, without a true RDMA transport initialized, `rs->rs_transport` is likely to be NULL, or at least not have implemented `get_mr`, making the whole thing a no-op.

But wait a minute, the `rs->rs_transport` is set during the binding or connecting phase. That makes more sense. Now the question is, if we're using something like `RDS_TCP`, does that transport *even* implement `get_mr`? I'd better double-check that part.

no matches

{
  "Expression": "get_mr",
  "PathPrefix": "net/rds/tcp"
}

{
  "error": "no matches"
}

gemini-3.1-pro-preview

null

null

							input: 14189
							output: 28
							thoughts: 32
						

Okay, let's see...

**Looking for `get_mr` in RDMA and TCP Transports**

Right, I'm thinking I need to find where memory registration is handled within the network stack, specifically related to RDMA, since TCP doesn't implement `get_mr`. I need to figure out how RDMA handles its memory registration. So, my next step is to dive into `net/rds/ib_rdma.c` or a file similarly named, related to the RDMA implementation. That's likely where the relevant `get_mr` functionality, or its equivalent, will be situated.

no matches

{
  "Expression": "get_mr",
  "PathPrefix": "net/rds/ib"
}

{
  "error": "no matches"
}

gemini-3.1-pro-preview

null

null

							input: 14395
							output: 28
							thoughts: 28
						

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

**Deconstructing `get_mr` in `rds_transport`**

Okay, so `get_mr` is a field within the `rds_transport` structure. My initial thought is, "Where exactly is this value being set?" I need to understand the assignment context to truly grasp its purpose and behavior. This is fundamental in debugging or understanding the flow. I need to trace back through the code and find the specific points where `get_mr` is populated. That's the only way to be able to understand the lifecycle of the field.

{
  "Expression": "\\.get_mr",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/ib.c=555=struct rds_transport rds_ib_transport = {\n--\nnet/rds/ib.c-572-\t.exit\t\t\t= rds_ib_exit,\nnet/rds/ib.c:573:\t.get_mr\t\t\t= rds_ib_get_mr,\nnet/rds/ib.c-574-\t.sync_mr\t\t= rds_ib_sync_mr,\n"
}

gemini-3.1-pro-preview

null

null

							input: 14702
							output: 32
							thoughts: 215
						

**RDMA Configuration Check**

Okay, so `rds_ib_transport` is the key – it implements `get_mr`, which is critical for the Remote Direct Memory Access (RDMA) functionality. And that transport is defined in `net/rds/ib.c`.  I know that file's compiled when `CONFIG_RDS_RDMA` is enabled. Therefore, to ensure I'm thoroughly testing the RDMA capabilities, I absolutely need `CONFIG_RDS_RDMA` to be set.  It's non-negotiable.

While I'm at it, I should verify whether `CONFIG_RDS_TCP` is also beneficial to have enabled.  I suspect it will be, so I should consider setting it too.

Right, let me add `RDS`, `RDS_RDMA`, and `RDS_TCP` to the `EnableConfigs`. That covers the basic setup.

Now, let's look at the symbols affected. My focus needs to include:
*   `__rds_rdma_map`
*   `rds_cmsg_rdma_args`
*   `rds_rdma_free_op`
*   `rds_atomic_free_op`
*   `rds_send_xmit`

Are there any other functions that have been modified? Ah, yes, `__rds_put_mr_final` appears to have been touched as well. That looks like a promising additional target to review.

{
  "Expression": "__rds_put_mr_final",
  "PathPrefix": "net/rds/"
}

{
  "Output": "net/rds/message.c=132=static void rds_message_purge(struct rds_message *rm)\n--\nnet/rds/message.c-176-\tif (rm-\u003erdma.op_rdma_mr)\nnet/rds/message.c:177:\t\tkref_put(\u0026rm-\u003erdma.op_rdma_mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/message.c-178-\n--\nnet/rds/message.c-181-\tif (rm-\u003eatomic.op_rdma_mr)\nnet/rds/message.c:182:\t\tkref_put(\u0026rm-\u003eatomic.op_rdma_mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/message.c-183-}\n--\nnet/rds/rdma.c=95=static void rds_destroy_mr(struct rds_mr *mr)\n--\nnet/rds/rdma.c-114-\nnet/rds/rdma.c:115:void __rds_put_mr_final(struct kref *kref)\nnet/rds/rdma.c-116-{\n--\nnet/rds/rdma.c=128=void rds_rdma_drop_keys(struct rds_sock *rs)\n--\nnet/rds/rdma.c-142-\t\tspin_unlock_irqrestore(\u0026rs-\u003ers_rdma_lock, flags);\nnet/rds/rdma.c:143:\t\tkref_put(\u0026mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/rdma.c-144-\t\tspin_lock_irqsave(\u0026rs-\u003ers_rdma_lock, flags);\n--\nnet/rds/rdma.c=173=static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args,\n--\nnet/rds/rdma.c-247-\t/* The MR can outlive its socket: a socket reference is held\nnet/rds/rdma.c:248:\t * until the final kref is dropped in __rds_put_mr_final().\nnet/rds/rdma.c-249-\t */\n--\nnet/rds/rdma.c-355-\tif (mr)\nnet/rds/rdma.c:356:\t\tkref_put(\u0026mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/rdma.c-357-\treturn ret;\n--\nnet/rds/rdma.c=400=int rds_free_mr(struct rds_sock *rs, sockptr_t optval, int optlen)\n--\nnet/rds/rdma.c-436-\nnet/rds/rdma.c:437:\tkref_put(\u0026mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/rdma.c-438-\treturn 0;\n--\nnet/rds/rdma.c=446=void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force)\n--\nnet/rds/rdma.c-482-\t/* Release the reference held above. */\nnet/rds/rdma.c:483:\tkref_put(\u0026mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/rdma.c-484-\n--\nnet/rds/rdma.c-487-\tif (zot_me)\nnet/rds/rdma.c:488:\t\tkref_put(\u0026mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/rdma.c-489-}\n--\nnet/rds/rdma.c=491=void rds_rdma_free_op(struct rm_rdma_op *ro)\n--\nnet/rds/rdma.c-495-\tif (ro-\u003eop_odp_mr) {\nnet/rds/rdma.c:496:\t\tkref_put(\u0026ro-\u003eop_odp_mr-\u003er_kref, __rds_put_mr_final);\nnet/rds/rdma.c-497-\t} else {\n--\nnet/rds/rdma.c=618=int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,\n--\nnet/rds/rdma.c-763-\t\t\t/* From here on the MR is torn down through\nnet/rds/rdma.c:764:\t\t\t * __rds_put_mr_final(), which drops this reference.\nnet/rds/rdma.c-765-\t\t\t */\n--\nnet/rds/rds.h=977=int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,\n--\nnet/rds/rds.h-979-\nnet/rds/rds.h:980:void __rds_put_mr_final(struct kref *kref);\nnet/rds/rds.h-981-\n"
}

gemini-3.1-pro-preview

null

null

							input: 14791
							output: 36
							thoughts: 0
						

{
  "File": "net/rds/rdma.c",
  "FirstLine": 110,
  "LineCount": 50
}

{
  "Contents": " 110:\t\n 111:\t\tif (trans_private)\n 112:\t\t\tmr-\u003er_trans-\u003efree_mr(trans_private, mr-\u003er_invalidate);\n 113:\t}\n 114:\t\n 115:\tvoid __rds_put_mr_final(struct kref *kref)\n 116:\t{\n 117:\t\tstruct rds_mr *mr = container_of(kref, struct rds_mr, r_kref);\n 118:\t\n 119:\t\trds_destroy_mr(mr);\n 120:\t\tsock_put(rds_rs_to_sk(mr-\u003er_sock));\n 121:\t\tkfree(mr);\n 122:\t}\n 123:\t\n 124:\t/*\n 125:\t * By the time this is called we can't have any more ioctls called on\n 126:\t * the socket so we don't need to worry about racing with others.\n 127:\t */\n 128:\tvoid rds_rdma_drop_keys(struct rds_sock *rs)\n 129:\t{\n 130:\t\tstruct rds_mr *mr;\n 131:\t\tstruct rb_node *node;\n 132:\t\tunsigned long flags;\n 133:\t\n 134:\t\t/* Release any MRs associated with this socket */\n 135:\t\tspin_lock_irqsave(\u0026rs-\u003ers_rdma_lock, flags);\n 136:\t\twhile ((node = rb_first(\u0026rs-\u003ers_rdma_keys))) {\n 137:\t\t\tmr = rb_entry(node, struct rds_mr, r_rb_node);\n 138:\t\t\tif (mr-\u003er_trans == rs-\u003ers_transport)\n 139:\t\t\t\tmr-\u003er_invalidate = 0;\n 140:\t\t\trb_erase(\u0026mr-\u003er_rb_node, \u0026rs-\u003ers_rdma_keys);\n 141:\t\t\tRB_CLEAR_NODE(\u0026mr-\u003er_rb_node);\n 142:\t\t\tspin_unlock_irqrestore(\u0026rs-\u003ers_rdma_lock, flags);\n 143:\t\t\tkref_put(\u0026mr-\u003er_kref, __rds_put_mr_final);\n 144:\t\t\tspin_lock_irqsave(\u0026rs-\u003ers_rdma_lock, flags);\n 145:\t\t}\n 146:\t\tspin_unlock_irqrestore(\u0026rs-\u003ers_rdma_lock, flags);\n 147:\t\n 148:\t\tif (rs-\u003ers_transport \u0026\u0026 rs-\u003ers_transport-\u003eflush_mrs)\n 149:\t\t\trs-\u003ers_transport-\u003eflush_mrs();\n 150:\t}\n 151:\t\n 152:\t/*\n 153:\t * Helper function to pin user pages.\n 154:\t */\n 155:\tstatic int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,\n 156:\t\t\t\tstruct page **pages, int write)\n 157:\t{\n 158:\t\tunsigned int gup_flags = FOLL_LONGTERM;\n 159:\t\tint ret;\n"
}

gemini-3.1-pro-preview

null

null

							input: 17433
							output: 243
							thoughts: 532
						

**My Fuzzing Strategy for RDS/RDMA**

Okay, let's nail down this fuzzing target. `__rds_put_mr_final` looks like a key point, since it's where the socket reference is dropped. This is the right place to start.

Therefore, the main symbols I want to focus the fuzzer on are: `__rds_put_mr_final`, naturally, but also `__rds_rdma_map`, `rds_rdma_free_op`, `rds_atomic_free_op`, and `rds_cmsg_rdma_args`. Those all seem directly related to the RDMA path and the reference counting issue.

Hmm, `rds_send_xmit`... that's a hot function, and I was originally hesitant to add it to the focus list because I don't want to skew the test distributions. However, the patch *specifically* modifies `rds_send_xmit` to fix a refcount leak when `rm->m_flags` has `RDS_MSG_ON_CONN` cleared. If I don't include it, the fuzzer might miss that part of the send path entirely. The entry point is `rds_sendmsg`, which means the fuzzer should spend some time in the send path. Therefore, I'm going to include `rds_send_xmit` because the fix is explicit in the patch.

Now, let me just double-check my configuration assumptions. I'm pretty sure `RDS` and `RDS_RDMA` are the main ones, but let me add `RDS_TCP` just to make sure I cover everything.

Alright, here's my summary:

WorthFuzzing: True
FocusSymbols:
- `__rds_put_mr_final`
- `__rds_rdma_map`
- `rds_rdma_free_op`
- `rds_atomic_free_op`
- `rds_cmsg_rdma_args`
- `rds_send_xmit`
EnableConfigs:
- `RDS`
- `RDS_RDMA`
- `RDS_TCP`

My reasoning is this: the patch fundamentally fixes a socket refcount leak within RDS RDMA operations. It does this by carefully managing socket references in `__rds_rdma_map` and `rds_cmsg_rdma_args`, and releasing them in `__rds_put_mr_final`. Additionally, `rds_rdma_free_op` and `rds_atomic_free_op` are changed to use non-sleeping page unpinning functions since they could be called from a tasklet context. This is very important. Finally, it corrects a message refcount leak in `rds_send_xmit`. These are all crucial functional changes in the RDS and RDMA logic itself, making them ideal fuzzing targets.

Okay, I'm confident. Time to call `set-results`.

{
  "EnableConfigs": [
    "RDS",
    "RDS_RDMA",
    "RDS_TCP"
  ],
  "FocusSymbols": [
    "__rds_put_mr_final",
    "__rds_rdma_map",
    "rds_rdma_free_op",
    "rds_atomic_free_op",
    "rds_cmsg_rdma_args",
    "rds_send_xmit"
  ],
  "Reasoning": "The patch fixes a socket refcount leak in RDS RDMA operations by holding a socket reference in `__rds_rdma_map` and `rds_cmsg_rdma_args` and releasing it in `__rds_put_mr_final`. It also modifies `rds_rdma_free_op` and `rds_atomic_free_op` to use non-sleeping page unpinning functions since they can be called from tasklet context. Finally, it fixes a message refcount leak in `rds_send_xmit`. These are functional changes in the core RDS and RDMA logic that should be fuzzed.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "RDS",
    "RDS_RDMA",
    "RDS_TCP"
  ],
  "FocusSymbols": [
    "__rds_put_mr_final",
    "__rds_rdma_map",
    "rds_rdma_free_op",
    "rds_atomic_free_op",
    "rds_cmsg_rdma_args",
    "rds_send_xmit"
  ],
  "Reasoning": "The patch fixes a socket refcount leak in RDS RDMA operations by holding a socket reference in `__rds_rdma_map` and `rds_cmsg_rdma_args` and releasing it in `__rds_put_mr_final`. It also modifies `rds_rdma_free_op` and `rds_atomic_free_op` to use non-sleeping page unpinning functions since they can be called from tasklet context. Finally, it fixes a message refcount leak in `rds_send_xmit`. These are functional changes in the core RDS and RDMA logic that should be fuzzed.",
  "WorthFuzzing": true
}