Skip to content
CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2026-72491

net/9p: fix race condition on rdma->state in trans_rdma.c

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
Linux

Description

In 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 products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 4cee2b8766045059d5e0b8114837b4a8efe827acaffected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 5424138848eb7d7d8a7196676e90a2cbf2142454affected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 3970a19a80de530b801b6256354d4a529a9a2d6caffected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 8aadc136d8e8d8fc95d7982d213cfe2234dfcf2baffected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 151f8cf5b23d8a534d884432a82a6d54d5a61989affected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 13bf9879b778b2f4b260b45bed18f31806120d1eaffected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < ebbcbe5c0db215feecc17def06178da443f4eea6affected
  • 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b to < 7d54894a1ee265a72d70f7cae1da6cc774cccc71affected
  • 3479b3c35e82ed10aa0ca2ee9e78c4eded06ba62affected
  • c01ddaa54d7411e964ffd250c018d8469c5852f2affected
  • 9e69c673fe077b8dc491cd8406c9bdcb1f76dee2affected
  • e48e7e27e4dfd00c81e0381e7cee610cce021452affected
  • 4.4.185 to < 4.5affected
  • 4.9.185 to < 4.10affected
  • 4.14.132 to < 4.15affected
  • 4.19.57 to < 4.20affected

Linux Linux

Default version status: affected

  • 4.20affected
  • 0 to < 4.20unaffected
  • 5.10.261 to ≤ 5.10.*unaffected
  • 5.15.212 to ≤ 5.15.*unaffected
  • 6.1.178 to ≤ 6.1.*unaffected
  • 6.6.145 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References