From 605d055452e7abed4aca012953aecc79c09baf12 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 12 Sep 2023 14:57:06 +0100 Subject: io_uring: break out of iowq iopoll on teardown [ upstream commit 45500dc4e01c167ee063f3dcc22f51ced5b2b1e9 ] io-wq will retry iopoll even when it failed with -EAGAIN. If that races with task exit, which sets TIF_NOTIFY_SIGNAL for all its workers, such workers might potentially infinitely spin retrying iopoll again and again and each time failing on some allocation / waiting / etc. Don't keep spinning if io-wq is dying. Fixes: 561fb04a6a225 ("io_uring: replace workqueue usage with io-wq") Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/io-wq.c | 10 ++++++++++ io_uring/io-wq.h | 1 + io_uring/io_uring.c | 2 ++ 3 files changed, 13 insertions(+) (limited to 'io_uring') diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c index 411bb2d1acd4..dc3d4b835622 100644 --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -181,6 +181,16 @@ static void io_worker_ref_put(struct io_wq *wq) complete(&wq->worker_done); } +bool io_wq_worker_stopped(void) +{ + struct io_worker *worker = current->worker_private; + + if (WARN_ON_ONCE(!io_wq_current_is_worker())) + return true; + + return test_bit(IO_WQ_BIT_EXIT, &worker->wqe->wq->state); +} + static void io_worker_cancel_cb(struct io_worker *worker) { struct io_wqe_acct *acct = io_wqe_get_acct(worker); diff --git a/io_uring/io-wq.h b/io_uring/io-wq.h index 31228426d192..31cc5cc9048c 100644 --- a/io_uring/io-wq.h +++ b/io_uring/io-wq.h @@ -52,6 +52,7 @@ void io_wq_hash_work(struct io_wq_work *work, void *val); int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask); int io_wq_max_workers(struct io_wq *wq, int *new_count); +bool io_wq_worker_stopped(void); static inline bool io_wq_is_hashed(struct io_wq_work *work) { diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 6d455e2428b9..7c8e81057eb1 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1823,6 +1823,8 @@ fail: if (!needs_poll) { if (!(req->ctx->flags & IORING_SETUP_IOPOLL)) break; + if (io_wq_worker_stopped()) + break; cond_resched(); continue; } -- cgit v1.2.3