diff options
| author | Xiaoguang Wang | 2020-02-22 14:46:05 +0800 |
|---|---|---|
| committer | Jens Axboe | 2020-02-22 07:45:03 -0700 |
| commit | c7849be9cc2dd2754c48ddbaca27c2de6d80a95d (patch) | |
| tree | f097b2326d01be9834bcad66d20b1818464db2f1 /fs | |
| parent | 7143b5ac5750f404ff3a594b34fdf3fc2f99f828 (diff) | |
io_uring: fix __io_iopoll_check deadlock in io_sq_thread
Since commit a3a0e43fd770 ("io_uring: don't enter poll loop if we have
CQEs pending"), if we already events pending, we won't enter poll loop.
In case SETUP_IOPOLL and SETUP_SQPOLL are both enabled, if app has
been terminated and don't reap pending events which are already in cq
ring, and there are some reqs in poll_list, io_sq_thread will enter
__io_iopoll_check(), and find pending events, then return, this loop
will never have a chance to exit.
I have seen this issue in fio stress tests, to fix this issue, let
io_sq_thread call io_iopoll_getevents() with argument 'min' being zero,
and remove __io_iopoll_check().
Fixes: a3a0e43fd770 ("io_uring: don't enter poll loop if we have CQEs pending")
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 27 |
1 files changed, 9 insertions, 18 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index b43467b3a8dc..de650df9ac53 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1672,11 +1672,17 @@ static void io_iopoll_reap_events(struct io_ring_ctx *ctx) mutex_unlock(&ctx->uring_lock); } -static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, - long min) +static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, + long min) { int iters = 0, ret = 0; + /* + * We disallow the app entering submit/complete with polling, but we + * still need to lock the ring to prevent racing with polled issue + * that got punted to a workqueue. + */ + mutex_lock(&ctx->uring_lock); do { int tmin = 0; @@ -1712,21 +1718,6 @@ static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, ret = 0; } while (min && !*nr_events && !need_resched()); - return ret; -} - -static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, - long min) -{ - int ret; - - /* - * We disallow the app entering submit/complete with polling, but we - * still need to lock the ring to prevent racing with polled issue - * that got punted to a workqueue. - */ - mutex_lock(&ctx->uring_lock); - ret = __io_iopoll_check(ctx, nr_events, min); mutex_unlock(&ctx->uring_lock); return ret; } @@ -5118,7 +5109,7 @@ static int io_sq_thread(void *data) */ mutex_lock(&ctx->uring_lock); if (!list_empty(&ctx->poll_list)) - __io_iopoll_check(ctx, &nr_events, 0); + io_iopoll_getevents(ctx, &nr_events, 0); else inflight = 0; mutex_unlock(&ctx->uring_lock); |