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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 45F35C43381 for ; Wed, 27 Mar 2019 18:11:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F2C1B217D9 for ; Wed, 27 Mar 2019 18:11:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="gpjuknid" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2C1B217D9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E30A36B027A; Wed, 27 Mar 2019 14:11:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DB96E6B027C; Wed, 27 Mar 2019 14:11:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AAB8D6B027D; Wed, 27 Mar 2019 14:11:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 62DA76B027A for ; Wed, 27 Mar 2019 14:11:15 -0400 (EDT) Received: by mail-pl1-f197.google.com with SMTP id a90so4812169pla.11 for ; Wed, 27 Mar 2019 11:11:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=+T44u5bIU/P3avjmDcSMpYAg984E4STk4hP/54qFw6c=; b=cnsPSY8rnqD7B1PSXlP+C36ugnAUdlX5szXUpP7SSXT+YN0TOvhQITX/vRG1yxQBDN UANyuOXpWoPDkcQnouOAWFCbzmf09UMYBx8Q3PUV8mbcodQ40DhFFrz4wo93d8ugrVrT bGF8LX1Mdx3/OzKXV3Ckr8KwRGZLrkY6l+HJusP5bBVcUfgZKTQ4tC+TpHYJAzM9GC69 xdJHP8bJn8m4rdWACVFDwa1S0/rsUPXEWHKgMDkIo37GM1bW0VTI4xx2R//BRGIRehaR zvlUXTqMy7PC2kkwccIRsrIh3mRUFhdFvE189946yfqIb1GGbIZcA7pfZtRbLMFbMKMb 6o3A== X-Gm-Message-State: APjAAAW5OcmMfPWJbaFkIbX/KmtOVMNHFFrv+4oqRv/xZ5eBZ5JzUbxT 64Gc5Nq0Yn24qt/RiVgmMvxT8E3Z9o1t9/YGVmb1dkVBYkiwmSrFG8BSVDNkgJ6y+rtqJfp2KoI XEqDsVlzJZfawRSnFoZj8bZHpMWT19kRdQ3OwMcWlavMYzk2ocqu0jJ44kEYOKNKddQ== X-Received: by 2002:a17:902:bd96:: with SMTP id q22mr29836913pls.322.1553710275011; Wed, 27 Mar 2019 11:11:15 -0700 (PDT) X-Google-Smtp-Source: APXvYqzblMgBhJeI0/Pggfq4a2NSf/yaQn1B2prpyx/V39I3OwLNlrlyDAptg7b+OF8HV2ZIfy3C X-Received: by 2002:a17:902:bd96:: with SMTP id q22mr29836833pls.322.1553710274150; Wed, 27 Mar 2019 11:11:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553710274; cv=none; d=google.com; s=arc-20160816; b=X10b6MdpUs115z8Gr4ynfCxzT0a58ZD2eQto3KPx9FB+k6PQ6UuBquSy3FTdg8fL2z DwjAfduRfeRQ2geSVCj5DcqsrFfPOxmJB5fleNM+fZzixWUObKU3f9eYkjTO8Z1hTixu /QQ91uGmuZVg6DgU6kKf7EdAamjXa2CZs7RXI9Hl11myfH++3q5MNvi8JZjKkF0ASWo7 yqjjYw+DuVnccHVcKgYBdpmBdDIvZzBp075trUD/HaYZ7OhwKkA5MtB280c9oLYWlhNZ /cq8jc1du594b3WlES+5VlE7KGjDgo5cwszc4c5YxWHSJhm6mbOtbFr/DvttOj91X4cp I3ZQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature; bh=+T44u5bIU/P3avjmDcSMpYAg984E4STk4hP/54qFw6c=; b=WsFyV5I6i8ZVy01BDtyejWCJQl8KPsoit/wgFDe9nmFcgeLrvFvucU+drpQXexADml VMTzja3JxPWFaJmyqT7L+f/xPcz5K524sk/54X4MfrmCjKMBR5Q596arB9C4rayiduY8 tSROhsGvzbVidnUwBo6daaBJuwrjTFcRqPHyo1I/NhKzrfJULWK5S7MGlkL3MoTU7mVD yyihImJkp2RguBLUempC2twVlClsbsABeSBcSMPdv4G5jwX9qPVhZBM1u/QiTBJpFG+T QxhDi++tq+codmM7l86W6mMDFmgS+LHZzemfzEmuQ8Q+ahW3YwhB16PH3sDHnfvLhyCU z/Kg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=gpjuknid; spf=pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sashal@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id y10si19329217pll.142.2019.03.27.11.11.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Mar 2019 11:11:14 -0700 (PDT) Received-SPF: pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=gpjuknid; spf=pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sashal@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org 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 4331621741; Wed, 27 Mar 2019 18:11:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710273; bh=jjyy72O1VbcZ/3O4FpFKkZSa8zUDlWIVltcMCUYuvQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gpjuknidbSXJc9S5Aw5EaotPfirqykXmQx6JegXQ4wSgYuDIo9l6/16f9tFTQGmNu vNhKksITohIjoPkg979h5oddZl9aNmgcPzEAfRqjIR8sRwzpBkRZkWgxTDHAXdcH4R zIOAgvJzdyfwqim2TkPpNUBsQXOrw+J3uCAZztZc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vlastimil Babka , Alexander Potapenko , Dmitry Vyukov , Andrea Arcangeli , "Kirill A. Shutemov" , Michal Hocko , David Rientjes , Yisheng Xie , zhong jiang , Andrew Morton , Linus Torvalds , Sasha Levin , linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.19 027/192] mm, mempolicy: fix uninit memory access Date: Wed, 27 Mar 2019 14:07:39 -0400 Message-Id: <20190327181025.13507-27-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327181025.13507-1-sashal@kernel.org> References: <20190327181025.13507-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Vlastimil Babka [ Upstream commit 2e25644e8da4ed3a27e7b8315aaae74660be72dc ] Syzbot with KMSAN reports (excerpt): ================================================================== BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:353 [inline] BUG: KMSAN: uninit-value in mpol_rebind_mm+0x249/0x370 mm/mempolicy.c:384 CPU: 1 PID: 17420 Comm: syz-executor4 Not tainted 4.20.0-rc7+ #15 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613 __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:295 mpol_rebind_policy mm/mempolicy.c:353 [inline] mpol_rebind_mm+0x249/0x370 mm/mempolicy.c:384 update_tasks_nodemask+0x608/0xca0 kernel/cgroup/cpuset.c:1120 update_nodemasks_hier kernel/cgroup/cpuset.c:1185 [inline] update_nodemask kernel/cgroup/cpuset.c:1253 [inline] cpuset_write_resmask+0x2a98/0x34b0 kernel/cgroup/cpuset.c:1728 ... Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline] kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176 kmem_cache_alloc+0x572/0xb90 mm/slub.c:2777 mpol_new mm/mempolicy.c:276 [inline] do_mbind mm/mempolicy.c:1180 [inline] kernel_mbind+0x8a7/0x31a0 mm/mempolicy.c:1347 __do_sys_mbind mm/mempolicy.c:1354 [inline] As it's difficult to report where exactly the uninit value resides in the mempolicy object, we have to guess a bit. mm/mempolicy.c:353 contains this part of mpol_rebind_policy(): if (!mpol_store_user_nodemask(pol) && nodes_equal(pol->w.cpuset_mems_allowed, *newmask)) "mpol_store_user_nodemask(pol)" is testing pol->flags, which I couldn't ever see being uninitialized after leaving mpol_new(). So I'll guess it's actually about accessing pol->w.cpuset_mems_allowed on line 354, but still part of statement starting on line 353. For w.cpuset_mems_allowed to be not initialized, and the nodes_equal() reachable for a mempolicy where mpol_set_nodemask() is called in do_mbind(), it seems the only possibility is a MPOL_PREFERRED policy with empty set of nodes, i.e. MPOL_LOCAL equivalent, with MPOL_F_LOCAL flag. Let's exclude such policies from the nodes_equal() check. Note the uninit access should be benign anyway, as rebinding this kind of policy is always a no-op. Therefore no actual need for stable inclusion. Link: http://lkml.kernel.org/r/a71997c3-e8ae-a787-d5ce-3db05768b27c@suse.cz Link: http://lkml.kernel.org/r/73da3e9c-cc84-509e-17d9-0c434bb9967d@suse.cz Signed-off-by: Vlastimil Babka Reported-by: syzbot+b19c2dc2c990ea657a71@syzkaller.appspotmail.com Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Andrea Arcangeli Cc: "Kirill A. Shutemov" Cc: Michal Hocko Cc: David Rientjes Cc: Yisheng Xie Cc: zhong jiang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 89d4439516f6..c716ba52fb9e 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -350,7 +350,7 @@ static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask) { if (!pol) return; - if (!mpol_store_user_nodemask(pol) && + if (!mpol_store_user_nodemask(pol) && !(pol->flags & MPOL_F_LOCAL) && nodes_equal(pol->w.cpuset_mems_allowed, *newmask)) return; -- 2.19.1