| From e677edbcabee849bfdd43f1602bccbecf736a646 Mon Sep 17 00:00:00 2001 |
| From: Jens Axboe <axboe@kernel.dk> |
| Date: Fri, 8 Apr 2022 11:08:58 -0600 |
| Subject: io_uring: fix race between timeout flush and removal |
| |
| From: Jens Axboe <axboe@kernel.dk> |
| |
| commit e677edbcabee849bfdd43f1602bccbecf736a646 upstream. |
| |
| 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 <axboe@kernel.dk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| fs/io_uring.c | 7 +++---- |
| 1 file changed, 3 insertions(+), 4 deletions(-) |
| |
| --- a/fs/io_uring.c |
| +++ b/fs/io_uring.c |
| @@ -1614,12 +1614,11 @@ static __cold void io_flush_timeouts(str |
| __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; |
| @@ -1636,7 +1635,6 @@ static __cold void io_flush_timeouts(str |
| if (events_got < events_needed) |
| break; |
| |
| - list_del_init(&req->timeout.list); |
| io_kill_timeout(req, 0); |
| } |
| ctx->cq_last_tm_flush = seq; |
| @@ -6223,6 +6221,7 @@ static int io_timeout_prep(struct io_kio |
| 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); |
| |
