From: Pavel Begunkov asml.silence@gmail.com
commit 12521a5d5cb7ff0ad43eadfc9c135d86e1131fa8 upstream.
Jiffy to ktime CQ waiting conversion broke how we treat timeouts, in particular we rearm it anew every time we get into io_cqring_wait_schedule() without adjusting the timeout. Waiting for 2 CQEs and getting a task_work in the middle may double the timeout value, or even worse in some cases task may wait indefinitely.
Cc: stable@vger.kernel.org Fixes: 228339662b398 ("io_uring: don't convert to jiffies for waiting on timeouts") Signed-off-by: Pavel Begunkov asml.silence@gmail.com Link: https://lore.kernel.org/r/f7bffddd71b08f28a877d44d37ac953ddb01590d.167291566... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/io_uring.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2364,7 +2364,7 @@ int io_run_task_work_sig(struct io_ring_ /* when returns >0, the caller should retry */ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx, struct io_wait_queue *iowq, - ktime_t timeout) + ktime_t *timeout) { int ret; unsigned long check_cq; @@ -2382,7 +2382,7 @@ static inline int io_cqring_wait_schedul if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) return -EBADR; } - if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS)) + if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS)) return -ETIME; return 1; } @@ -2452,7 +2452,7 @@ static int io_cqring_wait(struct io_ring } prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq, TASK_INTERRUPTIBLE); - ret = io_cqring_wait_schedule(ctx, &iowq, timeout); + ret = io_cqring_wait_schedule(ctx, &iowq, &timeout); cond_resched(); } while (ret > 0);