syzbot


WARNING in inc_nlink

Status: upstream: reported C repro on 2025/06/21 08:35
Reported-by: syzbot+1b98f5b9073182f3f902@syzkaller.appspotmail.com
First crash: 2d08h, last: 1d16h
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 WARNING in inc_nlink (2) C error 102 939d 1695d 0/1 upstream: reported C repro on 2020/11/01 15:25
linux-5.15 WARNING in inc_nlink origin:lts-only C done 573 1h12m 826d 0/3 upstream: reported C repro on 2023/03/20 05:26
upstream WARNING in inc_nlink (2) fs C inconclusive done 21 1203d 1540d 20/29 fixed on 2022/03/08 16:11
upstream WARNING in inc_nlink (3) fs C error error 6834 5d23h 1194d 0/29 upstream: reported C repro on 2022/03/17 16:37
linux-6.1 WARNING in inc_nlink 81 783d 805d 0/3 auto-obsoleted due to no activity on 2023/07/31 15:23
linux-4.19 WARNING in inc_nlink C done 8 1769d 1918d 1/1 fixed on 2020/09/18 07:23
linux-4.14 WARNING in inc_nlink C done 21 1777d 1919d 1/1 fixed on 2020/09/11 09:49
linux-4.14 WARNING in inc_nlink (2) C 47 855d 1690d 0/1 upstream: reported C repro on 2020/11/06 09:55
upstream WARNING in inc_nlink C done 26 1806d 1910d 15/29 fixed on 2020/09/16 22:51
linux-6.1 WARNING in inc_nlink (2) origin:upstream missing-backport C done 347 4h10m 542d 0/3 upstream: reported C repro on 2023/12/28 21:17

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5771 at fs/inode.c:389 inc_nlink+0x121/0x130 fs/inode.c:389
Modules linked in:
CPU: 1 PID: 5771 Comm: syz-executor243 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:inc_nlink+0x121/0x130 fs/inode.c:389
Code: 43 ea 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 19 43 ea ff e9 3f ff ff ff e8 0f 9c 91 ff <0f> 0b eb 82 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 41 57 41
RSP: 0018:ffffc9000447fc28 EFLAGS: 00010293
RAX: ffffffff81f3f9c1 RBX: ffff8880724311c8 RCX: ffff8880220f3c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88807658009b R09: 1ffff1100ecb0013
R10: dffffc0000000000 R11: ffffed100ecb0014 R12: dffffc0000000000
R13: 1ffff1100e486239 R14: ffff888072431170 R15: 0000000000000000
FS:  000055556b99e380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffed55fba88 CR3: 000000007e662000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 v9fs_vfs_mkdir_dotl+0x624/0x780 fs/9p/vfs_inode_dotl.c:431
 vfs_mkdir+0x296/0x440 fs/namei.c:4113
 do_mkdirat+0x1d4/0x440 fs/namei.c:4136
 __do_sys_mkdirat fs/namei.c:4151 [inline]
 __se_sys_mkdirat fs/namei.c:4149 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4149
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7e295f9ef9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed55fbb88 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007f7e295f9ef9
RDX: 0000000000000003 RSI: 0000200000000080 RDI: 00000000ffffff9c
RBP: 0030656c69662f2e R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 0000200000000040
R13: 0000200000000000 R14: 00007f7e2964304e R15: 0000000000000001
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/22 01:07 linux-6.6.y 6282921b6825 d6cdfb8a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in inc_nlink
2025/06/21 08:34 linux-6.6.y 6282921b6825 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in inc_nlink
2025/06/21 08:34 linux-6.6.y 6282921b6825 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in inc_nlink
* Struck through repros no longer work on HEAD.