From e677edbcabee849bfdd43f1602bccbecf736a646 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 8 Apr 2022 11:08:58 -0600 Subject: [PATCH] io_uring: fix race between timeout flush and removal io_flush_timeouts() assumes the timeout isn't in progress of triggering or being removed/canceled, so it unconditionally removes it from the timeout list and attempts to cancel it. Leave it on the list and let the normal timeout cancelation take care of it. Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Jens Axboe --- fs/io_uring.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index fafd1ca4780b6..659f8ecba5b79 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1736,12 +1736,11 @@ static __cold void io_flush_timeouts(struct io_ring_ctx *ctx) __must_hold(&ctx->completion_lock) { u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); + struct io_kiocb *req, *tmp; spin_lock_irq(&ctx->timeout_lock); - while (!list_empty(&ctx->timeout_list)) { + list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) { u32 events_needed, events_got; - struct io_kiocb *req = list_first_entry(&ctx->timeout_list, - struct io_kiocb, timeout.list); if (io_is_timeout_noseq(req)) break; @@ -1758,7 +1757,6 @@ static __cold void io_flush_timeouts(struct io_ring_ctx *ctx) if (events_got < events_needed) break; - list_del_init(&req->timeout.list); io_kill_timeout(req, 0); } ctx->cq_last_tm_flush = seq; @@ -6628,6 +6626,7 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0) return -EINVAL; + INIT_LIST_HEAD(&req->timeout.list); data->mode = io_translate_timeout_mode(flags); hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);