Medium · published July 25, 2026
In the Linux kernel, the following vulnerability has been resolved:
io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item
commit 10dc95939817 ("io_uring/io-wq: check IO_WQ_BIT_EXIT inside work
run loop") fixed the obvious case where io_worker_handle_work() took one
exit-bit snapshot before draining pending work, but the fix stops one
level too early.
io_worker_handle_work() now re-checks IO_WQ_BIT_EXIT in its outer work
run loop, yet it still snapshots that bit once before processing a whole
dependent linked-work chain. If io_wq_exit_start() sets IO_WQ_BIT_EXIT
after the first linked item has started, the remaining linked items can
still reuse stale do_kill = false, skip IO_WQ_WORK_CANCEL, and continue
running after exit has begun.
Move the check further inside, so it covers linked items too. Note: this
is a syzbot special as it loves setting up tons of slow linked work on
weird devices like msr that take forever to read, and immediately close
the ring. Exit then takes a long time.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 5.10.253, < 5.10.261 | 5.10.261 |
| linux/linux_kernel | ≥ 5.15.203, < 5.15.212 | 5.15.212 |
| linux/linux_kernel | ≥ 6.1.167, < 6.1.178 | 6.1.178 |
| linux/linux_kernel | ≥ 6.6.122, < 6.6.145 | 6.6.145 |
| linux/linux_kernel | ≥ 6.12.68, < 6.12.96 | 6.12.96 |
| linux/linux_kernel | ≥ 6.18.8, < 6.18.39 | 6.18.39 |
| linux/linux_kernel | ≥ 6.19.1, < 7.1.4 | 7.1.4 |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |