From patchwork Wed Nov 6 05:16:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11229295 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B7C7815AB for ; Wed, 6 Nov 2019 05:16:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6B00E217F4 for ; Wed, 6 Nov 2019 05:16:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="upSax/QB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B00E217F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C45056B0269; Wed, 6 Nov 2019 00:16:23 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id BF6EE6B026A; Wed, 6 Nov 2019 00:16:23 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B0B5E6B026B; Wed, 6 Nov 2019 00:16:23 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0084.hostedemail.com [216.40.44.84]) by kanga.kvack.org (Postfix) with ESMTP id 99ECD6B0269 for ; Wed, 6 Nov 2019 00:16:23 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 3E62C2C9D for ; Wed, 6 Nov 2019 05:16:23 +0000 (UTC) X-FDA: 76124691846.05.coil69_37b269a0d9208 X-Spam-Summary: 2,0,0,1414ba49181a8992,d41d8cd98f00b204,akpm@linux-foundation.org,:akpm@linux-foundation.org:guro@fb.com:hannes@cmpxchg.org::mhocko@suse.com:mm-commits@vger.kernel.org:shakeelb@google.com:stable@vger.kernel.org:torvalds@linux-foundation.org:vdavydov.dev@gmail.com,RULES_HIT:41:355:379:800:960:966:967:973:988:989:1260:1263:1345:1381:1431:1437:1535:1544:1605:1711:1730:1747:1777:1792:2196:2199:2393:2525:2559:2563:2682:2685:2859:2897:2899:2901:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3865:3866:3867:3868:3870:3871:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4117:4321:4385:5007:6119:6120:6238:6261:6653:7514:7576:7809:7903:8599:8660:9025:9163:9545:10004:10913:11026:11473:11658:11914:12043:12048:12296:12297:12438:12517:12519:12555:12679:12740:12783:12895:12986:13148:13221:13229:13230:13846:13870:14093:14096:14181:14721:14849:21080:21451:21622:21795:21939:30012:30029:30051:30054:30056:30064,0,RBL:error,CacheIP:none,Bayesian:0.5,0. 5,0.5,Ne X-HE-Tag: coil69_37b269a0d9208 X-Filterd-Recvd-Size: 6302 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Wed, 6 Nov 2019 05:16:22 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 551BF206A3; Wed, 6 Nov 2019 05:16:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573017381; bh=aH/jj0H4fMOvSzV5fvt6swlyJYSWxEBSqHHIoXLKLFM=; h=Date:From:To:Subject:From; b=upSax/QBfbsLXteQ4sH5d5fNopRj7PpMHPYSQdUnaDVhAquYUbMoTfYzrg4qvA+sX Co472BfVNqF+BGfFTQdGVII7xUq5il9up9IUriWDlEA9RLbPottL9FNY2j4wzBvTGF 4nxRkBEQam8R9opCKbgPn8QMPnSisbo5JspcjX5w= Date: Tue, 05 Nov 2019 21:16:21 -0800 From: akpm@linux-foundation.org To: akpm@linux-foundation.org, guro@fb.com, hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, shakeelb@google.com, stable@vger.kernel.org, torvalds@linux-foundation.org, vdavydov.dev@gmail.com Subject: [patch 01/17] mm: memcontrol: fix NULL-ptr deref in percpu stats flush Message-ID: <20191106051621.ptBmJsVW2%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 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: Shakeel Butt Subject: mm: memcontrol: fix NULL-ptr deref in percpu stats flush __mem_cgroup_free() can be called on the failure path in mem_cgroup_alloc(). However memcg_flush_percpu_vmstats() and memcg_flush_percpu_vmevents() which are called from __mem_cgroup_free() access the fields of memcg which can potentially be null if called from failure path from mem_cgroup_alloc(). Indeed syzbot has reported the following crash: R13: 00000000004bf27d R14: 00000000004db028 R15: 0000000000000003 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 30393 Comm: syz-executor.1 Not tainted 5.4.0-rc2+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memcg_flush_percpu_vmstats+0x4ae/0x930 mm/memcontrol.c:3436 Code: 05 41 89 c0 41 0f b6 04 24 41 38 c7 7c 08 84 c0 0f 85 5d 03 00 00 44 3b 05 33 d5 12 08 0f 83 e2 00 00 00 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 0f 85 91 03 00 00 48 8b 85 10 fe ff ff 48 8b b0 90 RSP: 0018:ffff888095c27980 EFLAGS: 00010206 RAX: 0000000000000012 RBX: ffff888095c27b28 RCX: ffffc90008192000 RDX: 0000000000040000 RSI: ffffffff8340fae7 RDI: 0000000000000007 RBP: ffff888095c27be0 R08: 0000000000000000 R09: ffffed1013f0da33 R10: ffffed1013f0da32 R11: ffff88809f86d197 R12: fffffbfff138b760 R13: dffffc0000000000 R14: 0000000000000090 R15: 0000000000000007 FS: 00007f5027170700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000710158 CR3: 00000000a7b18000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __mem_cgroup_free+0x1a/0x190 mm/memcontrol.c:5021 mem_cgroup_free mm/memcontrol.c:5033 [inline] mem_cgroup_css_alloc+0x3a1/0x1ae0 mm/memcontrol.c:5160 css_create kernel/cgroup/cgroup.c:5156 [inline] cgroup_apply_control_enable+0x44d/0xc40 kernel/cgroup/cgroup.c:3119 cgroup_mkdir+0x899/0x11b0 kernel/cgroup/cgroup.c:5401 kernfs_iop_mkdir+0x14d/0x1d0 fs/kernfs/dir.c:1124 vfs_mkdir+0x42e/0x670 fs/namei.c:3807 do_mkdirat+0x234/0x2a0 fs/namei.c:3830 __do_sys_mkdir fs/namei.c:3846 [inline] __se_sys_mkdir fs/namei.c:3844 [inline] __x64_sys_mkdir+0x5c/0x80 fs/namei.c:3844 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a59 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f502716fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007f502716fc90 RCX: 0000000000459a59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000180 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f50271706d4 R13: 00000000004bf27d R14: 00000000004db028 R15: 0000000000000003 Fixing this by moving the flush to mem_cgroup_free as there is no need to flush anything if we see failure in mem_cgroup_alloc(). Link: http://lkml.kernel.org/r/20191018165231.249872-1-shakeelb@google.com Fixes: bb65f89b7d3d ("mm: memcontrol: flush percpu vmevents before releasing memcg") Fixes: c350a99ea2b1 ("mm: memcontrol: flush percpu vmstats before releasing memcg") Signed-off-by: Shakeel Butt Reported-by: syzbot+515d5bcfe179cdf049b2@syzkaller.appspotmail.com Reviewed-by: Roman Gushchin Cc: Michal Hocko Cc: Johannes Weiner Cc: Vladimir Davydov Cc: Signed-off-by: Andrew Morton --- mm/memcontrol.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/mm/memcontrol.c~mm-memcontrol-fix-null-ptr-deref-in-percpu-stats-flush +++ a/mm/memcontrol.c @@ -5014,12 +5014,6 @@ static void __mem_cgroup_free(struct mem { int node; - /* - * Flush percpu vmstats and vmevents to guarantee the value correctness - * on parent's and all ancestor levels. - */ - memcg_flush_percpu_vmstats(memcg, false); - memcg_flush_percpu_vmevents(memcg); for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); free_percpu(memcg->vmstats_percpu); @@ -5030,6 +5024,12 @@ static void __mem_cgroup_free(struct mem static void mem_cgroup_free(struct mem_cgroup *memcg) { memcg_wb_domain_exit(memcg); + /* + * Flush percpu vmstats and vmevents to guarantee the value correctness + * on parent's and all ancestor levels. + */ + memcg_flush_percpu_vmstats(memcg, false); + memcg_flush_percpu_vmevents(memcg); __mem_cgroup_free(memcg); }