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io_uring: fix overflow resched cqe reordering

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Leaving the CQ critical section in the middle of a overflow flushing
can cause cqe reordering since the cache cq pointers are reset and any
new cqe emitters that might get called in between are not going to be
forced into io_cqe_cache_refill().

Fixes: eac2ca2d68 ("io_uring: check if we need to reschedule during overflow flush")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/90ba817f1a458f091f355f407de1c911d2b93bbf.1747483784.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2025-05-17 13:27:37 +01:00 • committed by Jens Axboe
parent f1774d9d4e
commit a7d755ed9c
1 changed files with 1 additions and 0 deletions
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io_uring/io_uring.c
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@ -636,6 +636,7 @@ static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool dying)
* to care for a non-real case.
*/
if (need_resched()) {
ctx->cqe_sentinel = ctx->cqe_cached;
io_cq_unlock_post(ctx);
mutex_unlock(&ctx->uring_lock);
cond_resched();