GHSA-GF38-F295-35CC
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In the Linux kernel, the following vulnerability has been resolved:
net/9p: fix race condition on rdma->state in trans_rdma.c
The rdma->state field is modified without holding req_lock in both recv_done() and p9_cm_event_handler(), while rdma_request() accesses the same field under the req_lock spinlock. This inconsistent locking creates a race condition:
-
recv_done() running in softirq completion context sets rdma->state = P9_RDMA_FLUSHING without acquiring req_lock
-
p9_cm_event_handler() modifies rdma->state at multiple points (ADDR_RESOLVED, ROUTE_RESOLVED, ESTABLISHED, CLOSED) without req_lock
-
rdma_request() uses spin_lock_irqsave(&rdma->req_lock, flags) to protect the read-modify-write of rdma->state
The race can cause lost state transitions: recv_done() or the CM event handler could set state to FLUSHING/CLOSED while rdma_request() is concurrently checking or modifying state under the lock, leading to the FLUSHING transition being silently overwritten by CLOSING. This corrupts the connection state machine and can cause use-after-free on RDMA request objects during teardown.
Fix by adding req_lock protection to all rdma->state modifications in recv_done() and p9_cm_event_handler(), matching the pattern already used in rdma_request(). Use spin_lock_irqsave/spin_unlock_irqrestore in the CM event handler since it can race with recv_done() which runs in softirq context.
Tested with a kernel module that races two threads (simulating rdma_request and recv_done/CM handler) on rdma->state with proper locking: 5.5M+ FLUSHING writes over 27M iterations with 0 lost transitions.
{
"affected": [],
"aliases": [
"CVE-2026-72491"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:23Z",
"severity": "CRITICAL"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/9p: fix race condition on rdma-\u003estate in trans_rdma.c\n\nThe rdma-\u003estate field is modified without holding req_lock in both\nrecv_done() and p9_cm_event_handler(), while rdma_request() accesses\nthe same field under the req_lock spinlock. This inconsistent locking\ncreates a race condition:\n\n- recv_done() running in softirq completion context sets\n rdma-\u003estate = P9_RDMA_FLUSHING without acquiring req_lock\n\n- p9_cm_event_handler() modifies rdma-\u003estate at multiple points\n (ADDR_RESOLVED, ROUTE_RESOLVED, ESTABLISHED, CLOSED) without\n req_lock\n\n- rdma_request() uses spin_lock_irqsave(\u0026rdma-\u003ereq_lock, flags) to\n protect the read-modify-write of rdma-\u003estate\n\nThe race can cause lost state transitions: recv_done() or the CM\nevent handler could set state to FLUSHING/CLOSED while rdma_request()\nis concurrently checking or modifying state under the lock, leading to\nthe FLUSHING transition being silently overwritten by CLOSING. This\ncorrupts the connection state machine and can cause use-after-free on\nRDMA request objects during teardown.\n\nFix by adding req_lock protection to all rdma-\u003estate modifications in\nrecv_done() and p9_cm_event_handler(), matching the pattern already\nused in rdma_request(). Use spin_lock_irqsave/spin_unlock_irqrestore\nin the CM event handler since it can race with recv_done() which runs\nin softirq context.\n\nTested with a kernel module that races two threads (simulating\nrdma_request and recv_done/CM handler) on rdma-\u003estate with proper\nlocking: 5.5M+ FLUSHING writes over 27M iterations with 0 lost\ntransitions.",
"id": "GHSA-gf38-f295-35cc",
"modified": "2026-08-17T06:33:33Z",
"published": "2026-08-15T06:32:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72491"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/13bf9879b778b2f4b260b45bed18f31806120d1e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/151f8cf5b23d8a534d884432a82a6d54d5a61989"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3970a19a80de530b801b6256354d4a529a9a2d6c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4cee2b8766045059d5e0b8114837b4a8efe827ac"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5424138848eb7d7d8a7196676e90a2cbf2142454"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7d54894a1ee265a72d70f7cae1da6cc774cccc71"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8aadc136d8e8d8fc95d7982d213cfe2234dfcf2b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ebbcbe5c0db215feecc17def06178da443f4eea6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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