Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: net/rds: use wq_has_sleeper() in release_in_xmit() release_in_xmit() clears RDS_IN_XMIT with clear_bit_unlock() and then checks waitqueue_active() to decide whether anyone needs waking. clear_bit_unlock() is only a release operation: it orders the critical section before the bit clear, but does not order the subsequent plain load of the wait queue head after it. The waiter side does the mirror image - it adds itself to the wait queue and then tests the bit. That is the classic store-buffering pattern: the releasing CPU can read the wait queue as empty while the waiting CPU still reads the bit as set, so the sleeper is never woken. The waiters are rds_conn_shutdown() and rds_tcp_reset_callbacks(), both in uninterruptible wait_event() with no timeout. A lost wake-up strands the shutdown worker on its single-threaded workqueue until some other sender releases the bit again - and on a connection that is being torn down precisely because it failed, there may never be another sender. The barrier used to be there: release_in_xmit() did clear_bit() followed by smp_mb__after_atomic() until commit 1422f28826d2 ("rds: introduce acquire/release ordering in acquire/release_in_xmit()") folded both into clear_bit_unlock(), which strengthened the lock hand-off but silently dropped the full barrier the wake-up check depends on. The refill counterpart, release_refill() in net/rds/ib_recv.c, still carries its smp_mb__after_atomic() for exactly this reason. Use wq_has_sleeper(), which is waitqueue_active() preceded by the required full barrier.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 1e1e4316fcaeb9cd6bc56c91127e88625237dd44 before 6f552364d97cf4005c7a58f11c9f79e14e269865; affected 8c378cc522aedd5fa5aa53486b43a4d552fbbd5c before a94b1dfc82454c5bc068e71c25393af674daf63b; affected 52287ed416a10bc3d3e204a3186d9509ab3ee634 before 5a806ed1eb46850ca4159a18b2a8c4b70f0c1341; affected 4a4dffdff9ea6201665f5d0a5042011d09bd527f before 3d401934b7edb3ccb07d982dabadd04c45ee307c; affected 1422f28826d2a0c11e5240b3e951c9e214d8656e before ed7ee0cd0e136d02f87f13181b1a89880463c7e9; affected 1422f28826d2a0c11e5240b3e951c9e214d8656e before a269795107f45adc95975a83324f8fef40bec4ce; affected 1422f28826d2a0c11e5240b3e951c9e214d8656e before 3764627b30a283e611e652c4a2bb8cdc74a75a99; affected 1422f28826d2a0c11e5240b3e951c9e214d8656e before 6d0c8b7073913011459cf968cbbadd341e166bc3; affected bec6c4ce1169a565c58c347d5d0ac22e46d507d6; affected f781fb5177cdfd9a6c98cd94e30275457c6461ac; affected 917135195200e20e5244b9c3f2bb40f3d5e02510; affected d792459a6e2ae21c7f5107babd63e52e4c5ab93a; affected 5.10.214 before 5.10.271; affected 5.15.153 before 5.15.222; affected 6.1.83 before 6.1.189; affected 6.6.23 before 6.6.158; affected 4.19.311 before 4.20; affected 5.4.273 before 5.5; affected 6.7.11 before 6.8; affected 6.8.2 before 6.9 |
| Linux / Linux | affected 6.9; unaffected 0 before 6.9; unaffected 5.10.271 through 5.10.*; unaffected 5.15.222 through 5.15.*; unaffected 6.1.189 through 6.1.*; unaffected 6.6.158 through 6.6.*; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/6f552364d97cf4005c7a58f11c9f79e14e269865
- https://git.kernel.org/stable/c/a94b1dfc82454c5bc068e71c25393af674daf63b
- https://git.kernel.org/stable/c/5a806ed1eb46850ca4159a18b2a8c4b70f0c1341
- https://git.kernel.org/stable/c/3d401934b7edb3ccb07d982dabadd04c45ee307c
- https://git.kernel.org/stable/c/ed7ee0cd0e136d02f87f13181b1a89880463c7e9
- https://git.kernel.org/stable/c/a269795107f45adc95975a83324f8fef40bec4ce
- https://git.kernel.org/stable/c/3764627b30a283e611e652c4a2bb8cdc74a75a99
- https://git.kernel.org/stable/c/6d0c8b7073913011459cf968cbbadd341e166bc3