From patchwork Wed Aug 26 12:02:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 264888 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=-10.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 D11B5C433E3 for ; Wed, 26 Aug 2020 12:06:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B81F20786 for ; Wed, 26 Aug 2020 12:06:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598443597; bh=b5EO4+AmusjhpfSUxjeTLp5l8RBm10R97KGtkUSvOuw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Um2SViXOdblC+FCKvMSh9xW0KVpLLkqUEQs+sRub0oJJdyWsZ7wZm27oRON6NN0lg z0ra4LiTr5tFBjB1R02AZkSmtaV4/fDGLMOTzHPUD2Tc+EzdxeWuVwEIT5NQn9+8ND QRbz3ngp2QAKAVlGpoZCKFQmAJ02hEU9mVmkY8Oo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729542AbgHZMGd (ORCPT ); Wed, 26 Aug 2020 08:06:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:38756 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729534AbgHZMDf (ORCPT ); Wed, 26 Aug 2020 08:03:35 -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 E200D208E4; Wed, 26 Aug 2020 12:03:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598443413; bh=b5EO4+AmusjhpfSUxjeTLp5l8RBm10R97KGtkUSvOuw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TUpYACMQV1b1SSK7FoIJIDMYeGNqnXgCedExN2NJg8AszvM6sKeHp80dBPjH4JhjF 55Q9W5iDIN0QjZSjkzVqujz0YdSIPiz9xxnx1/tRrIayt8RkemRvwIOMwmO4xT3i/b KmIlQxJkbIRTzMxs4vun4T4heImzg0x3vqLLuLeY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Roman Gershman , Pavel Begunkov Subject: [PATCH 5.8 15/16] io_uring: fix missing ->mm on exit Date: Wed, 26 Aug 2020 14:02:52 +0200 Message-Id: <20200826114911.967258227@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200826114911.216745274@linuxfoundation.org> References: <20200826114911.216745274@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pavel Begunkov Upstream commits: 8eb06d7e8dd85 ("io_uring: fix missing ->mm on exit") cbcf72148da4a ("io_uring: return locked and pinned page accounting") do_exit() first drops current->mm and then runs task_work, from where io_sq_thread_acquire_mm() would try to set mm for a user dying process. [ 208.004249] WARNING: CPU: 2 PID: 1854 at kernel/kthread.c:1238 kthread_use_mm+0x244/0x270 [ 208.004287] kthread_use_mm+0x244/0x270 [ 208.004288] io_sq_thread_acquire_mm.part.0+0x54/0x80 [ 208.004290] io_async_task_func+0x258/0x2ac [ 208.004291] task_work_run+0xc8/0x210 [ 208.004294] do_exit+0x1b8/0x430 [ 208.004295] do_group_exit+0x44/0xac [ 208.004296] get_signal+0x164/0x69c [ 208.004298] do_signal+0x94/0x1d0 [ 208.004299] do_notify_resume+0x18c/0x340 [ 208.004300] work_pending+0x8/0x3d4 Reported-by: Roman Gershman Tested-by: Roman Gershman Signed-off-by: Pavel Begunkov Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4363,7 +4363,8 @@ static int io_sq_thread_acquire_mm(struc struct io_kiocb *req) { if (io_op_defs[req->opcode].needs_mm && !current->mm) { - if (unlikely(!mmget_not_zero(ctx->sqo_mm))) + if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL) || + !mmget_not_zero(ctx->sqo_mm))) return -EFAULT; kthread_use_mm(ctx->sqo_mm); }