From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7661CC433E0 for ; Tue, 7 Jul 2020 15:28:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51D32206F6 for ; Tue, 7 Jul 2020 15:28:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594135700; bh=BLq+7ekXzyO3NbF70Wi6NnkYVRG+s2BoLo1H7UPaafU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0DBCTtoEELliUccU2XeF+kQpV45wg3Y5Q1IZI6nCFEtQwMbX6vxr8MIgRaNWE/+7W 9uLla4bdPjZfuTmDccIGJ61QRSv9qvTJKlLT08TwhHSwYQqt+oHKcwWWOsH4AQtfPP PGj78NMfgBHvwfE8ZmKBCBxgVCl6GscEm3blQyBo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729375AbgGGP2P (ORCPT ); Tue, 7 Jul 2020 11:28:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:42592 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729176AbgGGP2D (ORCPT ); Tue, 7 Jul 2020 11:28:03 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F16F320663; Tue, 7 Jul 2020 15:28:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594135682; bh=BLq+7ekXzyO3NbF70Wi6NnkYVRG+s2BoLo1H7UPaafU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bCGrX1ck6tOVZsA9/g1ojtqRTYcrXsOipcsu1jmWEJOZxvJIVomPNyToCKfhyoz24 Y/bHc5vQheGoKehncqOXT+6kqYbiDKj5dH0JVIy+qYJ1Xra472nS9pDuGa8bIGzjHR w1rNraIzg4Bs0OKucSXN8f+gUMc/KVqP7sB8dDi8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Agarwal, Anchal" , Jens Axboe , Sasha Levin Subject: [PATCH 5.4 01/65] io_uring: make sure async workqueue is canceled on exit Date: Tue, 7 Jul 2020 17:16:40 +0200 Message-Id: <20200707145752.491283624@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200707145752.417212219@linuxfoundation.org> References: <20200707145752.417212219@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jens Axboe Track async work items that we queue, so we can safely cancel them if the ring is closed or the process exits. Newer kernels handle this automatically with io-wq, but the old workqueue based setup needs a bit of special help to get there. There's no upstream variant of this, as that would require backporting all the io-wq changes from 5.5 and on. Hence I made a one-off that ensures that we don't leak memory if we have async work items that need active cancelation (like socket IO). Reported-by: Agarwal, Anchal Tested-by: Agarwal, Anchal Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/io_uring.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 7fa3cd3fff4d2..e0200406765c3 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -267,6 +267,9 @@ struct io_ring_ctx { #if defined(CONFIG_UNIX) struct socket *ring_sock; #endif + + struct list_head task_list; + spinlock_t task_lock; }; struct sqe_submit { @@ -331,14 +334,18 @@ struct io_kiocb { #define REQ_F_ISREG 2048 /* regular file */ #define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */ #define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */ +#define REQ_F_CANCEL 16384 /* cancel request */ unsigned long fsize; u64 user_data; u32 result; u32 sequence; + struct task_struct *task; struct fs_struct *fs; struct work_struct work; + struct task_struct *work_task; + struct list_head task_list; }; #define IO_PLUG_THRESHOLD 2 @@ -425,6 +432,8 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) INIT_LIST_HEAD(&ctx->cancel_list); INIT_LIST_HEAD(&ctx->defer_list); INIT_LIST_HEAD(&ctx->timeout_list); + INIT_LIST_HEAD(&ctx->task_list); + spin_lock_init(&ctx->task_lock); return ctx; } @@ -492,6 +501,7 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx) static inline void io_queue_async_work(struct io_ring_ctx *ctx, struct io_kiocb *req) { + unsigned long flags; int rw = 0; if (req->submit.sqe) { @@ -503,6 +513,13 @@ static inline void io_queue_async_work(struct io_ring_ctx *ctx, } } + req->task = current; + + spin_lock_irqsave(&ctx->task_lock, flags); + list_add(&req->task_list, &ctx->task_list); + req->work_task = NULL; + spin_unlock_irqrestore(&ctx->task_lock, flags); + queue_work(ctx->sqo_wq[rw], &req->work); } @@ -2201,6 +2218,8 @@ static void io_sq_wq_submit_work(struct work_struct *work) old_cred = override_creds(ctx->creds); async_list = io_async_list_from_sqe(ctx, req->submit.sqe); + + allow_kernel_signal(SIGINT); restart: do { struct sqe_submit *s = &req->submit; @@ -2232,6 +2251,12 @@ static void io_sq_wq_submit_work(struct work_struct *work) } if (!ret) { + req->work_task = current; + if (req->flags & REQ_F_CANCEL) { + ret = -ECANCELED; + goto end_req; + } + s->has_user = cur_mm != NULL; s->needs_lock = true; do { @@ -2246,6 +2271,12 @@ static void io_sq_wq_submit_work(struct work_struct *work) break; cond_resched(); } while (1); +end_req: + if (!list_empty(&req->task_list)) { + spin_lock_irq(&ctx->task_lock); + list_del_init(&req->task_list); + spin_unlock_irq(&ctx->task_lock); + } } /* drop submission reference */ @@ -2311,6 +2342,7 @@ static void io_sq_wq_submit_work(struct work_struct *work) } out: + disallow_signal(SIGINT); if (cur_mm) { set_fs(old_fs); unuse_mm(cur_mm); @@ -3675,12 +3707,32 @@ static int io_uring_fasync(int fd, struct file *file, int on) return fasync_helper(fd, file, on, &ctx->cq_fasync); } +static void io_cancel_async_work(struct io_ring_ctx *ctx, + struct task_struct *task) +{ + if (list_empty(&ctx->task_list)) + return; + + spin_lock_irq(&ctx->task_lock); + while (!list_empty(&ctx->task_list)) { + struct io_kiocb *req; + + req = list_first_entry(&ctx->task_list, struct io_kiocb, task_list); + list_del_init(&req->task_list); + req->flags |= REQ_F_CANCEL; + if (req->work_task && (!task || req->task == task)) + send_sig(SIGINT, req->work_task, 1); + } + spin_unlock_irq(&ctx->task_lock); +} + static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); + io_cancel_async_work(ctx, NULL); io_kill_timeouts(ctx); io_poll_remove_all(ctx); io_iopoll_reap_events(ctx); @@ -3688,6 +3740,16 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) io_ring_ctx_free(ctx); } +static int io_uring_flush(struct file *file, void *data) +{ + struct io_ring_ctx *ctx = file->private_data; + + if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) + io_cancel_async_work(ctx, current); + + return 0; +} + static int io_uring_release(struct inode *inode, struct file *file) { struct io_ring_ctx *ctx = file->private_data; @@ -3792,6 +3854,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, static const struct file_operations io_uring_fops = { .release = io_uring_release, + .flush = io_uring_flush, .mmap = io_uring_mmap, .poll = io_uring_poll, .fasync = io_uring_fasync, -- 2.25.1