From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933957AbeE0Fk5 (ORCPT ); Sun, 27 May 2018 01:40:57 -0400 Received: from mail-pl0-f68.google.com ([209.85.160.68]:42758 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932215AbeE0Fk4 (ORCPT ); Sun, 27 May 2018 01:40:56 -0400 X-Google-Smtp-Source: AB8JxZpX5HoBt/FiaDOerJfMCQ1UovkqpYIBvkUAQF8l/W7COzUSgtI+FjrJvraqzR18DaO6SDDR3my01Ct8MkG3fAc= MIME-Version: 1.0 In-Reply-To: <000000000000424989056d295959@google.com> References: <000000000000424989056d295959@google.com> From: Dmitry Vyukov Date: Sun, 27 May 2018 07:40:34 +0200 Message-ID: Subject: Re: net-next boot error: KASAN: use-after-free Write in call_usermodehelper_exec_work To: syzbot , netdev , David Miller Cc: LKML , mcgrof@kernel.org, syzkaller-bugs Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 27, 2018 at 7:34 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 5b79c2af667c Merge git://git.kernel.org/pub/scm/linux/kern.. > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=16087fa7800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e4078980b886800c > dashboard link: https://syzkaller.appspot.com/bug?extid=9269ae80345087b898d0 > compiler: gcc (GCC) 8.0.1 20180413 (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+9269ae80345087b898d0@syzkaller.appspotmail.com This first happened just now on net-next, so +net maintainers. This happened during boot, so no separate reproducer. > FS-Cache: Loaded > CacheFiles: Loaded > pnp: PnP ACPI init > pnp: PnP ACPI: found 7 devices > ================================================================== > BUG: KASAN: use-after-free in call_usermodehelper_exec_work+0x2d3/0x310 > kernel/umh.c:195 > Write of size 4 at addr ffff8801d63bd370 by task kworker/u4:0/6 > > CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 4.17.0-rc6+ #65 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: events_unbound call_usermodehelper_exec_work > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1b9/0x294 lib/dump_stack.c:113 > print_address_description+0x6c/0x20b mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 > __asan_report_store4_noabort+0x17/0x20 mm/kasan/report.c:437 > call_usermodehelper_exec_work+0x2d3/0x310 kernel/umh.c:195 > process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 > worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 > kthread+0x345/0x410 kernel/kthread.c:240 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > Allocated by task 1: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 > kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 > kmalloc include/linux/slab.h:512 [inline] > kzalloc include/linux/slab.h:701 [inline] > call_usermodehelper_setup+0xe8/0x400 kernel/umh.c:382 > clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: > 2085701024 ns > kobject_uevent_env+0xb21/0x1110 lib/kobject_uevent.c:608 > kobject_uevent+0x1f/0x30 lib/kobject_uevent.c:636 > device_add+0xb01/0x16d0 drivers/base/core.c:1843 > device_create_groups_vargs+0x1ff/0x270 drivers/base/core.c:2439 > device_create_vargs drivers/base/core.c:2479 [inline] > device_create+0xd3/0x100 drivers/base/core.c:2515 > chr_dev_init+0x120/0x158 drivers/char/mem.c:938 > do_one_initcall+0x127/0x913 init/main.c:884 > do_initcall_level init/main.c:952 [inline] > do_initcalls init/main.c:960 [inline] > do_basic_setup init/main.c:978 [inline] > kernel_init_freeable+0x49b/0x58e init/main.c:1135 > kernel_init+0x11/0x1b3 init/main.c:1061 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > Freed by task 1296: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > NET: Registered protocol family 2 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xd9/0x260 mm/slab.c:3813 > call_usermodehelper_freeinfo kernel/umh.c:45 [inline] > umh_complete+0x7b/0x90 kernel/umh.c:59 > call_usermodehelper_exec_async+0x6e8/0x9e0 kernel/umh.c:116 > tcp_listen_portaddr_hash hash table entries: 4096 (order: 6, 294912 bytes) > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > The buggy address belongs to the object at ffff8801d63bd300 > which belongs to the cache kmalloc-192 of size 192 > The buggy address is located 112 bytes inside of > 192-byte region [ffff8801d63bd300, ffff8801d63bd3c0) > The buggy address belongs to the page: > TCP established hash table entries: 65536 (order: 7, 524288 bytes) > page:ffffea000758ef40 count:1 mapcount:0 mapping:ffff8801d63bd000 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffff8801d63bd000 0000000000000000 0000000100000010 > TCP bind hash table entries: 65536 (order: 10, 4194304 bytes) > raw: ffffea000759c2e0 ffffea0007521be0 ffff8801da800040 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801d63bd200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801d63bd280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >> >> ffff8801d63bd300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > TCP: Hash tables configured (established 65536 bind 65536) > ^ > ffff8801d63bd380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801d63bd400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > UDP hash table entries: 4096 (order: 7, 655360 bytes) > UDP-Lite hash table entries: 4096 (order: 7, 655360 bytes) > > > --- > 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#bug-status-tracking for how to communicate with > syzbot. > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/000000000000424989056d295959%40google.com. > For more options, visit https://groups.google.com/d/optout.