io_uring: fix __io_iopoll_check deadlock in io_sq_thread
Since commita3a0e43fd7
("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:a3a0e43fd7
("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>
This commit is contained in:
Родитель
7143b5ac57
Коммит
c7849be9cc
|
@ -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);
|
||||
|
|
Загрузка…
Ссылка в новой задаче