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=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B0CBAC282DD for ; Mon, 10 Jun 2019 09:30:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FB0520859 for ; Mon, 10 Jun 2019 09:30:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388770AbfFJJaH (ORCPT ); Mon, 10 Jun 2019 05:30:07 -0400 Received: from mail-io1-f69.google.com ([209.85.166.69]:37469 "EHLO mail-io1-f69.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388380AbfFJJaG (ORCPT ); Mon, 10 Jun 2019 05:30:06 -0400 Received: by mail-io1-f69.google.com with SMTP id j18so7108277ioj.4 for ; Mon, 10 Jun 2019 02:30:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=Np+xPJWikxtIIlIvGvVx4ZfVKde2a2GTO356MNseHYo=; b=jgqjHfoqTDqz37qexxOpEsTq11cEhkUCvsOoqKbFCe5Y/H3sPCzUsN22D+kyPvMYyQ sH+K/Hvd5BiSe4lOIBtoHn8D5+p1lWH3NLxAFBtAwmUizDt5zYr8F0z/xds+Ukiv8qcU a5LMhPaTa4DSHiTZp2ucfCXFNaV6cIV/1VK9Yq/J8YhqKDMKI66Wp3rcARAxZF2Cj4vH 5Z0N8IYl/FA0cD+vbP8Gpmuu6QlpTG4K+rq15oT/vJMwO649xoocvycwUbG4hpeeYeM2 uPQ3s1ombALYCz9sYiPECwtAe/AQEZoHiLkTZt1AMkNs+bkKgMIzSIDVEMvnc+zTH0m6 wk+Q== X-Gm-Message-State: APjAAAWZY37a5iHX+KVacln6SeUROd3RbJHVF3Si7+G4/9X1tgrijUN/ ligBzPzkV0Pa3FNidoDZjWIdDJLD4/WfiaD/om5qvlBPkr8d X-Google-Smtp-Source: APXvYqz2M+f0Q17h76RoBB7choSL+vGIvH++EpNIaPAzhimyQwDJcGoElZVdPCA72l9rTJFgMT/hvree53vNcYjlWWDhxWCDz0Rs MIME-Version: 1.0 X-Received: by 2002:a24:690f:: with SMTP id e15mr378569itc.31.1560159005811; Mon, 10 Jun 2019 02:30:05 -0700 (PDT) Date: Mon, 10 Jun 2019 02:30:05 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000055aba7058af4d378@google.com> Subject: KASAN: null-ptr-deref Read in css_task_iter_advance From: syzbot To: ast@kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, daniel@iogearbox.net, hannes@cmpxchg.org, kafai@fb.com, linux-kernel@vger.kernel.org, lizefan@huawei.com, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, tj@kernel.org, yhs@fb.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 3f310e51 Add linux-next specific files for 20190607 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=170acfa6a00000 kernel config: https://syzkaller.appspot.com/x/.config?x=5d176e1849bbc45 dashboard link: https://syzkaller.appspot.com/bug?extid=d4bba5ccd4f9a2a68681 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+d4bba5ccd4f9a2a68681@syzkaller.appspotmail.com ================================================================== BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: null-ptr-deref in css_task_iter_advance+0x240/0x540 kernel/cgroup/cgroup.c:4503 Read of size 4 at addr 0000000000000004 by task syz-executor.2/26575 CPU: 1 PID: 26575 Comm: syz-executor.2 Not tainted 5.2.0-rc3-next-20190607 #11 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+0x172/0x1f0 lib/dump_stack.c:113 __kasan_report.cold+0x5/0x36 mm/kasan/report.c:486 kasan_report+0x12/0x20 mm/kasan/common.c:614 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:94 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] css_task_iter_advance+0x240/0x540 kernel/cgroup/cgroup.c:4503 css_task_iter_start+0x18b/0x230 kernel/cgroup/cgroup.c:4543 __cgroup_procs_start.isra.0+0x32f/0x400 kernel/cgroup/cgroup.c:4638 cgroup_procs_start kernel/cgroup/cgroup.c:4660 [inline] cgroup_procs_start+0x1e7/0x260 kernel/cgroup/cgroup.c:4647 cgroup_seqfile_start+0xa4/0xd0 kernel/cgroup/cgroup.c:3752 kernfs_seq_start+0xdc/0x190 fs/kernfs/file.c:118 seq_read+0x2a7/0x1110 fs/seq_file.c:224 kernfs_fop_read+0xed/0x560 fs/kernfs/file.c:252 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_preadv+0x1c4/0x280 fs/read_write.c:1089 __do_sys_preadv fs/read_write.c:1139 [inline] __se_sys_preadv fs/read_write.c:1134 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1134 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 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:00007f4ee9fa8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459279 RDX: 0000000000000001 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4ee9fa96d4 R13: 00000000004c6376 R14: 00000000004dae78 R15: 00000000ffffffff ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.