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io_uring: fix CQ waiting timeout handling

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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.1672915663.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Pavel Begunkov 2023-01-05 10:49:15 +00:00 committed by Greg Kroah-Hartman
parent b7b9bc9305
commit c3222fd282
1 changed files with 3 additions and 3 deletions
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6
io_uring/io_uring.c
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@ -7598,7 +7598,7 @@ static int io_run_task_work_sig(void)
/* 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;
@ -7610,7 +7610,7 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
if (test_bit(0, &ctx->check_cq_overflow))
return 1;
if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS))
if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS))
return -ETIME;
return 1;
}
@ -7673,7 +7673,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
}
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);
finish_wait(&ctx->cq_wait, &iowq.wq);
cond_resched();
} while (ret > 0);