syzbot


WARNING in inc_nlink (2)

Status: upstream: reported C repro on 2023/12/28 21:17
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+9e9d439464190b89a70c@syzkaller.appspotmail.com
First crash: 711d, last: 4h07m
Fix commit to backport (bisect log) :
tree: upstream
commit fb6f20ecb121cef4d7946f834a6ee867c4e21b4a
Author: Jan Kara <jack@suse.cz>
Date: Thu Oct 17 10:28:23 2024 +0000

  reiserfs: The last commit

  
Fix bisection: failed (error log, bisect log)
  
Bug presence (3)
Date Name Commit Repro Result
2024/12/27 linux-6.1.y (ToT) 563edd786f0a C [report] WARNING in inc_nlink
2023/12/29 upstream (ToT) 8735c7c84d1b C [report] WARNING in inc_nlink
2024/12/27 upstream (ToT) d6ef8b40d075 C Didn't crash
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 WARNING in inc_nlink origin:lts-only -1 C 22 30d 170d 0/2 upstream: reported C repro on 2025/06/21 08:35
linux-4.19 WARNING in inc_nlink (2) -1 C error 102 1107d 1863d 0/1 upstream: reported C repro on 2020/11/01 15:25
linux-5.15 WARNING in inc_nlink origin:lts-only -1 C done 771 3d17h 994d 0/3 upstream: reported C repro on 2023/03/20 05:26
upstream WARNING in inc_nlink (2) fs -1 C inconclusive done 21 1371d 1708d 20/29 fixed on 2022/03/08 16:11
upstream WARNING in inc_nlink (3) fs -1 C error error 6903 1d00h 1362d 0/29 upstream: reported C repro on 2022/03/17 16:37
linux-6.1 WARNING in inc_nlink -1 81 951d 973d 0/3 auto-obsoleted due to no activity on 2023/07/31 15:23
linux-4.19 WARNING in inc_nlink -1 C done 8 1937d 2086d 1/1 fixed on 2020/09/18 07:23
linux-4.14 WARNING in inc_nlink -1 C done 21 1945d 2087d 1/1 fixed on 2020/09/11 09:49
linux-4.14 WARNING in inc_nlink (2) -1 C 47 1023d 1858d 0/1 upstream: reported C repro on 2020/11/06 09:55
upstream WARNING in inc_nlink -1 C done 26 1975d 2078d 15/29 fixed on 2020/09/16 22:51
Fix bisection attempts (5)
Created Duration User Patch Repo Result
2025/01/31 12:21 3h48m fix candidate upstream OK (1) job log
2024/08/14 23:18 2m bisect fix linux-6.1.y error job log
2024/07/05 01:13 1h28m bisect fix linux-6.1.y OK (0) job log log
2024/03/20 09:43 1h03m bisect fix linux-6.1.y OK (0) job log log
2024/02/01 03:08 1h06m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
loop0: detected capacity change from 0 to 128
VFS: Found a Xenix FS (block size = 1024) on device loop0
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4435 at fs/inode.c:389 inc_nlink+0x11d/0x130 fs/inode.c:389
Modules linked in:
CPU: 0 PID: 4435 Comm: syz.0.17 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:inc_nlink+0x11d/0x130 fs/inode.c:389
Code: 78 eb ff e9 3a ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 4c ff ff ff 48 89 df e8 ad 78 eb ff e9 3f ff ff ff e8 13 5c 9b ff <0f> 0b eb 82 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 41
RSP: 0018:ffffc90003497d60 EFLAGS: 00010293
RAX: ffffffff81e5624d RBX: ffff88806ded8080 RCX: ffff8880731b8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed1002ec2b57
R10: ffffed1002ec2b57 R11: 1ffff11002ec2b56 R12: dffffc0000000000
R13: 1ffff1100dbdb010 R14: ffff88806ded8038 R15: 0000000000000000
FS:  000055556720a500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d763fff CR3: 000000002ffe1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 inode_inc_link_count include/linux/fs.h:2576 [inline]
 sysv_mkdir+0x1d/0x120 fs/sysv/namei.c:119
 vfs_mkdir+0x387/0x570 fs/namei.c:4106
 do_mkdirat+0x1d0/0x430 fs/namei.c:4131
 __do_sys_mkdir fs/namei.c:4151 [inline]
 __se_sys_mkdir fs/namei.c:4149 [inline]
 __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4149
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1f9b78ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe76f26c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007f1f9b9b5fa0 RCX: 00007f1f9b78ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007f1f9b811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1f9b9b5fa0 R14: 00007f1f9b9b5fa0 R15: 0000000000000002
 </TASK>

Crashes (452):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/26 15:28 linux-6.1.y 0bc96de781b4 bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan WARNING in inc_nlink
2024/10/28 03:25 linux-6.1.y 7ec6f9fa3d97 65e8686b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan WARNING in inc_nlink
2023/12/29 06:44 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/12/04 22:10 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/08/26 14:47 linux-6.1.y 0bc96de781b4 bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/05/18 04:57 linux-6.1.y 02b72ccb5f9d f41472b0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/02/05 07:57 linux-6.1.y 0cbb5f65e52f 5896748e .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2024/04/14 09:36 linux-6.1.y cd5d98c0556c c8349e48 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/12/08 20:42 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/12/05 03:54 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/12/04 00:10 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/10/04 00:42 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/10/01 02:21 linux-6.1.y 7b34dc04e4ff 65a0eece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/09/16 00:46 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/09/08 02:25 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2023/12/28 21:16 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in inc_nlink
2025/12/06 08:34 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/12/04 21:18 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/12/03 12:32 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/12/02 11:38 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/12/02 07:37 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/12/01 16:38 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/30 14:57 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/30 11:18 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/29 20:57 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/29 10:04 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/27 10:45 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/16 22:32 linux-6.1.y f6e38ae624cf f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/11 19:32 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/10 17:25 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/09 09:46 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/09 05:38 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/04 21:00 linux-6.1.y f6e38ae624cf 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/02 14:30 linux-6.1.y f6e38ae624cf 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/11/02 00:19 linux-6.1.y f6e38ae624cf 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/30 11:47 linux-6.1.y f6e38ae624cf fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/27 08:41 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/27 06:16 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/27 05:01 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/26 23:43 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/26 16:48 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/23 19:36 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/04 17:40 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/04 16:50 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/03 22:42 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/01 03:26 linux-6.1.y 7b34dc04e4ff 65a0eece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/10/01 01:13 linux-6.1.y 7b34dc04e4ff 65a0eece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/09/30 12:50 linux-6.1.y 7b34dc04e4ff 86341da6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/09/26 10:48 linux-6.1.y 7b34dc04e4ff 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/09/16 13:25 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/09/16 06:14 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
2025/09/13 15:29 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in inc_nlink
* Struck through repros no longer work on HEAD.