From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753416AbeCaUtf (ORCPT ); Sat, 31 Mar 2018 16:49:35 -0400 Received: from mail-it0-f72.google.com ([209.85.214.72]:57308 "EHLO mail-it0-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751647AbeCaUrH (ORCPT ); Sat, 31 Mar 2018 16:47:07 -0400 X-Google-Smtp-Source: AIpwx49u6vXNmdNXEyO44SuHkW8V10YCt4JmFoGdnZI43miEbss3FqyTc1fVeAhMQfYAvUq6PjyRL/ziA8beUY6pXDexX6is2hgL MIME-Version: 1.0 Date: Sat, 31 Mar 2018 13:47:06 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <001a113ed49eb535d20568bb75ba@google.com> Subject: KASAN: slab-out-of-bounds Read in find_first_zero_bit From: syzbot To: aivazian.tigran@gmail.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot hit the following crash on upstream commit b5dbc28762fd3fd40ba76303be0c7f707826f982 (Sat Mar 31 04:53:57 2018 +0000) Merge tag 'kbuild-fixes-v4.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=a88c8270030dc5d71e4f C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6431707947335680 syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=6420485734662144 Raw console output: https://syzkaller.appspot.com/x/log.txt?id=6746019962290176 Kernel config: https://syzkaller.appspot.com/x/.config?id=-2760467897697295172 compiler: gcc (GCC) 7.1.1 20170620 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a88c8270030dc5d71e4f@syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer. ================================================================== BUG: KASAN: slab-out-of-bounds in find_first_zero_bit+0xc5/0xe0 lib/find_bit.c:125 Read of size 8 at addr ffff8801d7480a00 by task syzkaller291450/4476 CPU: 1 PID: 4476 Comm: syzkaller291450 Not tainted 4.16.0-rc7+ #8 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 find_first_zero_bit+0xc5/0xe0 lib/find_bit.c:125 bfs_create+0xf7/0x610 fs/bfs/dir.c:92 lookup_open+0x1217/0x1970 fs/namei.c:3200 do_last fs/namei.c:3291 [inline] path_openat+0xd76/0x3530 fs/namei.c:3519 do_filp_open+0x25b/0x3b0 fs/namei.c:3554 do_sys_open+0x502/0x6d0 fs/open.c:1059 SYSC_open fs/open.c:1077 [inline] SyS_open+0x2d/0x40 fs/open.c:1072 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4404f9 RSP: 002b:00007ffd2305ebd8 EFLAGS: 00000207 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004404f9 RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000020000340 RBP: 0000000000000003 R08: 000000000000000a R09: 6f6f6c2f7665642f R10: 0000000000000000 R11: 0000000000000207 R12: 0000000000000004 R13: 0000000000401d70 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 4476: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 __do_kmalloc mm/slab.c:3706 [inline] __kmalloc+0x162/0x760 mm/slab.c:3715 kmalloc include/linux/slab.h:517 [inline] kzalloc include/linux/slab.h:701 [inline] bfs_fill_super+0x3d3/0xea0 fs/bfs/inode.c:362 mount_bdev+0x2b7/0x370 fs/super.c:1119 bfs_mount+0x34/0x40 fs/bfs/inode.c:465 mount_fs+0x66/0x2d0 fs/super.c:1222 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:2509 [inline] do_new_mount fs/namespace.c:2512 [inline] do_mount+0xea4/0x2bb0 fs/namespace.c:2842 SYSC_mount fs/namespace.c:3058 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3035 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 2830: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3486 [inline] kfree+0xd9/0x260 mm/slab.c:3801 single_release+0x88/0xb0 fs/seq_file.c:606 __fput+0x327/0x7e0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8801d7480a00 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 0 bytes inside of 32-byte region [ffff8801d7480a00, ffff8801d7480a20) The buggy address belongs to the page: page:ffffea00075d2000 count:1 mapcount:0 mapping:ffff8801d7480000 index:0xffff8801d7480fc1 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801d7480000 ffff8801d7480fc1 000000010000003f raw: ffffea00075d1ea0 ffffea00075d32a0 ffff8801dac001c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d7480900: 00 02 fc fc fc fc fc fc 00 02 fc fc fc fc fc fc ffff8801d7480980: 00 02 fc fc fc fc fc fc 00 fc fc fc fc fc fc fc > ffff8801d7480a00: 07 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc ^ ffff8801d7480a80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ffff8801d7480b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ================================================================== --- This bug is generated by a dumb bot. 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