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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 07455C433DF for ; Thu, 2 Jul 2020 01:24:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9AC920874 for ; Thu, 2 Jul 2020 01:24:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653091; bh=FeJYSWpPkEj16ll5EuwSvsmJPTgeQNhCZZ/l+eCp2w8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BvanW/y8HTjDN4/LeGUTlsVetQI1NtmwABIlPn7ytMxRbCX8QaHTJANDzwTBjLF7g fqds2WGjrWxtCIJG5cerBY8Meu/hf2LEUBb48bPMJ8YPyoDuaBv2fZWr8ARrrLE2ir 30K/mijAoCYuueTGdhxRY8+dagv01wUf9bczB7Bw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728552AbgGBBX5 (ORCPT ); Wed, 1 Jul 2020 21:23:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:54746 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728536AbgGBBX4 (ORCPT ); Wed, 1 Jul 2020 21:23:56 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4BBF12145D; Thu, 2 Jul 2020 01:23:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653036; bh=FeJYSWpPkEj16ll5EuwSvsmJPTgeQNhCZZ/l+eCp2w8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LEpsozyf6RMXApLZrXyeYiLc92fWqrtut31jAJvEuJWAkkmqigAyOkVoLeeC3tlyZ dbsKuOiparlf1nZNc5FGSCY0M0nfXijdvlJf7HpZRUbm/5GLkMcq6+d/Ko1ZHSPMid 8XvdYLkzpXXGEMWTTLVpE71faGWImnyXBx5jgZ1A= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Pavel Begunkov , Jens Axboe , Sasha Levin , io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.7 49/53] io_uring: fix current->mm NULL dereference on exit Date: Wed, 1 Jul 2020 21:21:58 -0400 Message-Id: <20200702012202.2700645-49-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200702012202.2700645-1-sashal@kernel.org> References: <20200702012202.2700645-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org From: Pavel Begunkov [ Upstream commit d60b5fbc1ce8210759b568da49d149b868e7c6d3 ] Don't reissue requests from io_iopoll_reap_events(), the task may not have mm, which ends up with NULL. It's better to kill everything off on exit anyway. [ 677.734670] RIP: 0010:io_iopoll_complete+0x27e/0x630 ... [ 677.734679] Call Trace: [ 677.734695] ? __send_signal+0x1f2/0x420 [ 677.734698] ? _raw_spin_unlock_irqrestore+0x24/0x40 [ 677.734699] ? send_signal+0xf5/0x140 [ 677.734700] io_iopoll_getevents+0x12f/0x1a0 [ 677.734702] io_iopoll_reap_events.part.0+0x5e/0xa0 [ 677.734703] io_ring_ctx_wait_and_kill+0x132/0x1c0 [ 677.734704] io_uring_release+0x20/0x30 [ 677.734706] __fput+0xcd/0x230 [ 677.734707] ____fput+0xe/0x10 [ 677.734709] task_work_run+0x67/0xa0 [ 677.734710] do_exit+0x35d/0xb70 [ 677.734712] do_group_exit+0x43/0xa0 [ 677.734713] get_signal+0x140/0x900 [ 677.734715] do_signal+0x37/0x780 [ 677.734717] ? enqueue_hrtimer+0x41/0xb0 [ 677.734718] ? recalibrate_cpu_khz+0x10/0x10 [ 677.734720] ? ktime_get+0x3e/0xa0 [ 677.734721] ? lapic_next_deadline+0x26/0x30 [ 677.734723] ? tick_program_event+0x4d/0x90 [ 677.734724] ? __hrtimer_get_next_event+0x4d/0x80 [ 677.734726] __prepare_exit_to_usermode+0x126/0x1c0 [ 677.734741] prepare_exit_to_usermode+0x9/0x40 [ 677.734742] idtentry_exit_cond_rcu+0x4c/0x60 [ 677.734743] sysvec_reschedule_ipi+0x92/0x160 [ 677.734744] ? asm_sysvec_reschedule_ipi+0xa/0x20 [ 677.734745] asm_sysvec_reschedule_ipi+0x12/0x20 Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/io_uring.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6cf9d509371e2..43dc745727408 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -858,6 +858,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_files_update *ip, unsigned nr_args); static int io_grab_files(struct io_kiocb *req); +static void io_complete_rw_common(struct kiocb *kiocb, long res); static void io_cleanup_req(struct io_kiocb *req); static int io_file_get(struct io_submit_state *state, struct io_kiocb *req, int fd, struct file **out_file, bool fixed); @@ -1697,6 +1698,14 @@ static void io_iopoll_queue(struct list_head *again) do { req = list_first_entry(again, struct io_kiocb, list); list_del(&req->list); + + /* shouldn't happen unless io_uring is dying, cancel reqs */ + if (unlikely(!current->mm)) { + io_complete_rw_common(&req->rw.kiocb, -EAGAIN); + io_put_req(req); + continue; + } + refcount_inc(&req->refs); io_queue_async_work(req); } while (!list_empty(again)); -- 2.25.1