From a7d755ed9ce9738af3db602eb29d32774a180bc7 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sat, 17 May 2025 13:27:37 +0100 Subject: [PATCH] io_uring: fix overflow resched cqe reordering 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: eac2ca2d682f9 ("io_uring: check if we need to reschedule during overflow flush") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/90ba817f1a458f091f355f407de1c911d2b93bbf.1747483784.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 1 + 1 file changed, 1 insertion(+) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 541e65a1eebfd..edda31a15c6e6 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -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(); -- 2.39.5