syzbot


WARNING in inc_nlink

Status: fixed on 2020/09/18 07:23
Reported-by: syzbot+ba2febbc0330db7925b6@syzkaller.appspotmail.com
Fix commit: 169f7f37bd6b fs/minix: don't allow getting deleted inodes
First crash: 825d, last: 676d

Fix bisection: fixed by (bisect log) :
commit 169f7f37bd6b0bb91242099cc261219791067d5c
Author: Eric Biggers <ebiggers@google.com>
Date: Wed Aug 12 01:35:27 2020 +0000

  fs/minix: don't allow getting deleted inodes

similar bugs (6):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 WARNING in inc_nlink (2) C error 94 4d14h 601d 0/1 upstream: reported C repro on 2020/11/01 15:25
upstream WARNING in inc_nlink (2) C inconclusive done 21 110d 447d 22/22 fixed on 2022/03/08 16:11
upstream WARNING in inc_nlink (3) C error 128 4d12h 100d 0/22 upstream: reported C repro on 2022/03/17 16:37
linux-4.14 WARNING in inc_nlink C done 21 683d 826d 1/1 fixed on 2020/09/11 09:49
linux-4.14 WARNING in inc_nlink (2) C 47 5d04h 597d 0/1 upstream: reported C repro on 2020/11/06 09:55
upstream WARNING in inc_nlink C done 26 713d 816d 17/22 fixed on 2020/09/16 22:51

Sample crash report:
audit: type=1400 audit(1590023469.462:8): avc:  denied  { execmem } for  pid=6439 comm="syz-executor080" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
MINIX-fs: mounting unchecked file system, running fsck is recommended
------------[ cut here ]------------
WARNING: CPU: 1 PID: 6439 at fs/inode.c:343 inc_nlink.cold+0x11/0x18 fs/inode.c:343
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 6439 Comm: syz-executor080 Not tainted 4.19.124-syzkaller #0
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+0x1fc/0x2fe lib/dump_stack.c:118
 panic+0x26a/0x50e kernel/panic.c:186
 __warn.cold+0x20/0x46 kernel/panic.c:541
 report_bug+0x262/0x2a0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 fixup_bug arch/x86/kernel/traps.c:173 [inline]
 do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:inc_nlink.cold+0x11/0x18 fs/inode.c:343
Code: 51 b9 ff 44 89 e0 5b 5d 41 5c c3 e8 20 ff ee ff eb c3 e8 29 ff ee ff eb 8e e8 02 51 b9 ff 48 c7 c7 80 c9 74 87 e8 2f f6 a4 ff <0f> 0b e9 48 86 ff ff e8 ea 50 b9 ff 48 8d 7b 40 b8 ff ff 37 00 48
RSP: 0018:ffff88808ead7d88 EFLAGS: 00010282
RAX: 0000000000000024 RBX: ffff888082f97960 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81534081 RDI: ffffed1011d5afa3
RBP: 0000000000000000 R08: 0000000000000024 R09: ffffed1015ce5081
R10: ffffed1015ce5080 R11: ffff8880ae728407 R12: ffff888082f979a8
R13: ffff888083735080 R14: 00000000000000fa R15: 0000000000000000
 inode_inc_link_count include/linux/fs.h:2098 [inline]
 minix_mkdir+0x71/0x1b0 fs/minix/namei.c:117
 vfs_mkdir+0x423/0x6a0 fs/namei.c:3819
 do_mkdirat+0x21e/0x280 fs/namei.c:3842
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x444a59
Code: 0d d8 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 db d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdd3e0dab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffdd3e0dac0 RCX: 0000000000444a59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000240
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000400e40
R10: 00007ffdd3e0d990 R11: 0000000000000246 R12: 00000000004026c0
R13: 0000000000402750 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (8):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/05/21 01:14 linux-4.19.y 1bab61d3e8cd 4afdfa20 .config log report syz C
ci2-linux-4-19 2020/04/04 08:14 linux-4.19.y dda0e2920330 ef26b610 .config log report syz C
ci2-linux-4-19 2020/03/26 22:52 linux-4.19.y 54b4fa6d3955 6d25c5a0 .config log report syz C
ci2-linux-4-19 2020/03/24 14:28 linux-4.19.y 14cfdbd39e31 33e14df3 .config log report syz C
ci2-linux-4-19 2020/03/23 08:08 linux-4.19.y 14cfdbd39e31 78267cec .config log report syz C
ci2-linux-4-19 2020/05/21 02:36 linux-4.19.y 1bab61d3e8cd 4afdfa20 .config log report
ci2-linux-4-19 2020/05/20 04:39 linux-4.19.y 258f0cf7ac3b 6d882fd2 .config log report
ci2-linux-4-19 2020/03/23 07:47 linux-4.19.y 14cfdbd39e31 78267cec .config log report