From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2375C6FC9 for ; Sun, 17 Sep 2023 19:37:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80B31C433C8; Sun, 17 Sep 2023 19:37:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694979445; bh=1Yl8j9PPMwlhrNxyVHCfm+gxBxThgvHIYORL8Ts7r8Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xk9s9MdD25MPOzuO/ZxcPpUHwlkQ2V9FE3b2VLx3Sr099UqH21KaSinqUlA7FFaqN cXtyl1a3TCFxEXkkfpG2ec+9O1bRo9z6bqLdahgCovAOpS3NafUXTNkfWIz5lq6b0L lIWuID6ng4WHW5ptBERhKdZd/dvSempjDZYKdes4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pavel Begunkov , Jens Axboe Subject: [PATCH 5.10 315/406] io_uring: break out of iowq iopoll on teardown Date: Sun, 17 Sep 2023 21:12:49 +0200 Message-ID: <20230917191109.617401551@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230917191101.035638219@linuxfoundation.org> References: <20230917191101.035638219@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavel Begunkov [ 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 | 3 ++- 3 files changed, 13 insertions(+), 1 deletion(-) --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -176,6 +176,16 @@ static void io_worker_ref_put(struct io_ complete(&wq->worker_done); } +bool io_wq_worker_stopped(void) +{ + struct io_worker *worker = current->pf_io_worker; + + 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); --- a/io_uring/io-wq.h +++ b/io_uring/io-wq.h @@ -129,6 +129,7 @@ void io_wq_hash_work(struct io_wq_work * 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) { --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -6898,7 +6898,8 @@ static void io_wq_submit_work(struct io_ */ if (ret != -EAGAIN || !(req->ctx->flags & IORING_SETUP_IOPOLL)) break; - + if (io_wq_worker_stopped()) + break; /* * If REQ_F_NOWAIT is set, then don't wait or retry with * poll. -EAGAIN is final for that case.