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, 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 5B05CC43381 for ; Wed, 27 Mar 2019 18:17:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0E52621741 for ; Wed, 27 Mar 2019 18:17:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="MUvQZIES" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E52621741 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 095296B0286; Wed, 27 Mar 2019 14:17:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 01A996B0288; Wed, 27 Mar 2019 14:17:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DFDE26B0289; Wed, 27 Mar 2019 14:17:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 961806B0286 for ; Wed, 27 Mar 2019 14:17:01 -0400 (EDT) Received: by mail-pf1-f199.google.com with SMTP id z26so14634879pfa.7 for ; Wed, 27 Mar 2019 11:17:01 -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=jDVBzzK+WLpPQuthFGnYHZWjDVTFJrtG5e/s0YG+j3o=; b=dPkZwlVIWMOXKgqLMn1Pswo/c7ntm7p35ZlaQpq2W8UGL7qxUHZOIuMMDqW5FbwFZt 38YMvWqY9YseSz5KJavv3S8jHejosgxcss60cDDEFgYDybpSlZ35JC6OTFOQxn9Zz4pr qOj08WCjfRjbj7201I+4A9jEBz7WlOtd3B5jLhZINklAp8pb8o2OwRhlWSWGJCZDOWxJ BrpDsFa82WHc21sY4TVY4pjOkdoMXrRn1mt1p+YlmLeXABmtBpVq4V8LfIlcZqSeiUgf +awz3ODAjZj9aLH8L6CjAvXrjGB5uGC30X566pQnWbWP7VdQ65kliUCol9bDDSAnv5kO xHjA== X-Gm-Message-State: APjAAAVEszR6kG3Ku60+nPQ1EDw6yJYQbK5dO5pevpF5dgahrJd423XA l+vMJ5eJq6HPV7WpfzV0/xvBV+9bBWkRjKnUlZy++JNL1fTE2sdXNZ+iRDoSE85yazvaR3ulQuj QJYsLNNEojU/QZJ+oXhYSeW/76iBZD+i3MUWy0HQ4KBazSErUW7v3h4U97Opz0RRDUg== X-Received: by 2002:a17:902:6b03:: with SMTP id o3mr38339479plk.126.1553710621252; Wed, 27 Mar 2019 11:17:01 -0700 (PDT) X-Google-Smtp-Source: APXvYqxVzE2ctFJQK1jfb5wl2HPKoOXukexj18sDEK4VHSe/9GLGlyusirDn/KRmK9/02+qGuMp0 X-Received: by 2002:a17:902:6b03:: with SMTP id o3mr38339426plk.126.1553710620543; Wed, 27 Mar 2019 11:17:00 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553710620; cv=none; d=google.com; s=arc-20160816; b=dBUxI6vD6ryV+722fQiyOFjIOF2Oh3xq4f8I3dnAs1COtjn8yVvN9gVa0KVYqzN6i5 /BbgwvJXeaBJweJW6zPb8600YR1rnNG3anrLhlohc4kSCsYETliU6dRVU6lkii//S0Q6 +RLQ0h6TN/Sb4JkAhr2zasfgqs94+d9JQ/JT4zGXXltQh7hFksr8OWtiTBZNB5+0e0Jh KvEvEeb95yxuI7NTK/415MS1TkvFS88PoNuTUkAMh/1115akeKVF2j5DflQKz5NUEunf 8rYspqENVnZjOe/FhC/EUDTL4HtH4kSts1uiHKEIg5DpvBbtJx8D6wT9ydIbjOiSMMTk aztg== 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=jDVBzzK+WLpPQuthFGnYHZWjDVTFJrtG5e/s0YG+j3o=; b=nIVDt3e4WbOxntHxMlS2mZfkXcD5h57XRCg9telAFjk+ThZbtF4TjLZt/m1LOmVWdl UtcnDUEdrtN/v9JwJbN1Db9bPzYPf8y8o/9uwlyg4jdfO3RRvjIDdQtbqbEaUq0Bp87w XSe+znzTAxKpKHe9/yB3u+RCazXKDzxux1710/XrsA8gEYFYCEFkQ41I0tf2TRkMKa7T Dc+UckB1Pb0sb49pulgD8U3OhXLWQ7eVYDJiIl45WPE2H+IpI08XaCP9AAsnHBbt7hh7 GUReKqbitcovj7bAtpFW4dG01nC3bgJghRLgQZixxH0/EdtcEeBVW1qTkwXPGTeCdn5h n3Qw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=MUvQZIES; 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 129si1118882pfz.159.2019.03.27.11.17.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Mar 2019 11:17:00 -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=MUvQZIES; 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 A13F92082F; Wed, 27 Mar 2019 18:16:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710620; bh=vZlZSwjI0j1qTEE66ehzHcxXT94pw+35NscVhJmlVwM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MUvQZIES8fuCF9Xm/nBZwSY3SNN4pqVIhmWtohyvMv+ji+BmA0J1EHKl9bm0ge8V/ ckUQb2U0KOxjhNcWueuV2AYceYiMQrkaApNXfTzVPgKrT7xa3VUfsblC1nh8C//a5u YtIWnbUb5ssChU/5piR7grexKJ921bpx53r2QzTo= 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 4.14 017/123] mm, mempolicy: fix uninit memory access Date: Wed, 27 Mar 2019 14:14:41 -0400 Message-Id: <20190327181628.15899-17-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327181628.15899-1-sashal@kernel.org> References: <20190327181628.15899-1-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 1331645a3794..b0e99ea0c3db 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -349,7 +349,7 @@ 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