CVE-2026-43314 — linux / linux_kernel
Missing Release of Resource after Effective LifetimeIn the Linux kernel, the following vulnerability has been resolved:
dm: remove fake timeout to avoid leak request
Since commit 15f73f5b3e59 ("blk-mq: move failure injection out of blk_mq_complete_request"), drivers are responsible for calling blk_should_fake_timeout() at appropriate code paths and opportunities.
However, the dm driver does not implement its own timeout handler and relies on the timeout handling of its slave devices.
If an io-timeout-fail error is injected to a dm device, the request will be leaked and never completed, causing tasks to hang indefinitely.
Reproduce:
- prepare dm which has iscsi slave device
- inject io-timeout-fail to dm echo 1 >/sys/class/block/dm-0/io-timeout-fail echo 100 >/sys/kernel/debug/fail_io_timeout/probability echo 10 >/sys/kernel/debug/fail_io_timeout/times
- read/write dm
- iscsiadm -m node -u
Result: hang task like below [ 862.243768] INFO: task kworker/u514:2:151 blocked for more than 122 seconds. [ 862.244133] Tainted: G E 6.19.0-rc1+ #51 [ 862.244337] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 862.244718] task:kworker/u514:2 state:D stack:0 pid:151 tgid:151 ppid:2 task_flags:0x4288060 flags:0x00080000 [ 862.245024] Workqueue: iscsi_ctrl_3:1 __iscsi_unbind_session [scsi_transport_iscsi] [ 862.245264] Call Trace: [ 862.245587] <TASK> [ 862.245814] __schedule+0x810/0x15c0 [ 862.246557] schedule+0x69/0x180 [ 862.246760] blk_mq_freeze_queue_wait+0xde/0x120 [ 862.247688] elevator_change+0x16d/0x460 [ 862.247893] elevator_set_none+0x87/0xf0 [ 862.248798] blk_unregister_queue+0x12e/0x2a0 [ 862.248995] __del_gendisk+0x231/0x7e0 [ 862.250143] del_gendisk+0x12f/0x1d0 [ 862.250339] sd_remove+0x85/0x130 [sd_mod] [ 862.250650] device_release_driver_internal+0x36d/0x530 [ 862.250849] bus_remove_device+0x1dd/0x3f0 [ 862.251042] device_del+0x38a/0x930 [ 862.252095] __scsi_remove_device+0x293/0x360 [ 862.252291] scsi_remove_target+0x486/0x760 [ 862.252654] __iscsi_unbind_session+0x18a/0x3e0 [scsi_transport_iscsi] [ 862.252886] process_one_work+0x633/0xe50 [ 862.253101] worker_thread+0x6df/0xf10 [ 862.253647] kthread+0x36d/0x720 [ 862.254533] ret_from_fork+0x2a6/0x470 [ 862.255852] ret_from_fork_asm+0x1a/0x30 [ 862.256037] </TASK>
Remove the blk_should_fake_timeout() check from dm, as dm has no native timeout handling and should not attempt to fake timeouts.
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | 2.6.31 | 5.10.252 |
| linux / linux_kernel | 5.11 | 5.15.202 |
| linux / linux_kernel | 5.16 | 6.1.165 |
| linux / linux_kernel | 6.2 | 6.6.128 |
| linux / linux_kernel | 6.7 | 6.12.75 |
| linux / linux_kernel | 6.13 | 6.18.16 |
| linux / linux_kernel | 6.19 | 6.19.6 |
- https://git.kernel.org/stable/c/4f9e7ca933a9fbf9912a384b061a00c77332cbf0
- https://git.kernel.org/stable/c/6cdb21e0c9fdee484feba14fc9e72e9d07daf9f3
- https://git.kernel.org/stable/c/8200fca818c1e2f65bc6cb16d934ff6049302197
- https://git.kernel.org/stable/c/b307b6307f6459841312432bd4bc9519cbac97f5
- https://git.kernel.org/stable/c/c8a23d4c995ef4227bd4de64cd3910637ee6162e
- https://git.kernel.org/stable/c/cf2d06c9fd4b6521ea5b7f73c99c64c2c6f5e224
- https://git.kernel.org/stable/c/ece6720de9403260088209b0b92d45e0b49ff856
- https://git.kernel.org/stable/c/f3a9c95a15d2f4466acad5c68faeff79ca5e9f47
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