[syzbot] WARNING in inc_nlink (3)

[syzbot <syzbot+2b3af42c0644df1e4da9@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    aad611a868d1 Merge tag 'perf-tools-fixes-for-v5.17-2022-03..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11ae4ede700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=aba0ab2928a512c2
dashboard link: https://syzkaller.appspot.com/bug?extid=2b3af42c0644df1e4da9
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12b9eb31700000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1429c4c5700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2b3af42c0644df1e4da9@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 3 PID: 3671 at fs/inode.c:388 inc_nlink+0x144/0x160 fs/inode.c:388
Modules linked in:
CPU: 3 PID: 3671 Comm: syz-executor254 Not tainted 5.17.0-rc7-syzkaller-00235-gaad611a868d1 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:inc_nlink+0x144/0x160 fs/inode.c:388
Code: ff 4c 89 e7 e8 0d 97 ec ff e9 42 ff ff ff 4c 89 e7 e8 90 96 ec ff e9 fc fe ff ff 4c 89 e7 e8 83 96 ec ff eb d4 e8 9c b0 a5 ff <0f> 0b e9 6e ff ff ff e8 80 96 ec ff e9 44 ff ff ff e8 76 96 ec ff
RSP: 0018:ffffc900027cfcc0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff8880266e06c0 RCX: 0000000000000000
RDX: ffff888022f24100 RSI: ffffffff81d244f4 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: ffff8880266e0183
R10: ffffffff81d24460 R11: 000000000000001d R12: ffff8880266e0708
R13: ffff888026531d78 R14: ffff8880266e00f8 R15: ffff88801d309c00
FS:  00005555565363c0(0000) GS:ffff88802ca00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564785040878 CR3: 000000001626c000 CR4: 0000000000150ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 v9fs_vfs_mkdir_dotl+0x478/0x770 fs/9p/vfs_inode_dotl.c:454
 vfs_mkdir+0x1c3/0x3b0 fs/namei.c:3933
 do_mkdirat+0x285/0x300 fs/namei.c:3959
 __do_sys_mkdir fs/namei.c:3979 [inline]
 __se_sys_mkdir fs/namei.c:3977 [inline]
 __x64_sys_mkdir+0xf2/0x140 fs/namei.c:3977
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f5da8ba5829
Code: 28 c3 e8 5a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd6deb21e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffd6deb21f8 RCX: 00007f5da8ba5829
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200002c0
RBP: 00007ffd6deb21f0 R08: 00007f5da8b63af0 R09: 00007f5da8b63af0
R10: 0000000020000340 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>


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