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io_uring: fix CQ waiting timeout handling 

commit 12521a5d5c 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: 228339662b ("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 3c09dbaf6e
commit b026bb1617
1 changed files with 3 additions and 3 deletions
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6
io_uring/io_uring.c
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@ -2206,7 +2206,7 @@ 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;
unsigned long check_cq;
@ -2224,7 +2224,7 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
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;
}
@ -2289,7 +2289,7 @@ 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);
cond_resched();
} while (ret > 0);