[moderation] [fs?] WARNING in vfs_remove_acl (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c612261bedd6 Merge tag 'io_uring-7.0-20260320' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11980b52580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6754c86e8d9e4c91
dashboard link: https://syzkaller.appspot.com/bug?extid=11ef4849e6440d660951
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c8cd1384ea7c/disk-c612261b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9583e81cf450/vmlinux-c612261b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/55f234507bbe/bzImage-c612261b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+11ef48...@syzkaller.appspotmail.com

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DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff888057ee1b58, owner = 0x0, curr 0xffff8880355ebd00, list empty
WARNING: kernel/locking/rwsem.c:1381 at __up_write kernel/locking/rwsem.c:1380 [inline], CPU#0: syz.2.185/6635
WARNING: kernel/locking/rwsem.c:1381 at up_write+0x2d6/0x410 kernel/locking/rwsem.c:1643, CPU#0: syz.2.185/6635
Modules linked in:
CPU: 0 UID: 0 PID: 6635 Comm: syz.2.185 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__up_write kernel/locking/rwsem.c:1380 [inline]
RIP: 0010:up_write+0x388/0x410 kernel/locking/rwsem.c:1643
Code: cc 8b 49 c7 c2 a0 ec cc 8b 4c 0f 44 d0 48 8b 7c 24 08 48 c7 c6 00 ef cc 8b 48 8b 14 24 4c 89 f1 4d 89 e0 4c 8b 4c 24 10 41 52 <67> 48 0f b9 3a 48 83 c4 08 e8 2a 5f 0a 03 e9 67 fd ff ff 48 c7 c1
RSP: 0018:ffffc90004aa7bd0 EFLAGS: 00010246
RAX: ffffffff8bccec80 RBX: ffff888057ee1b58 RCX: ffff888057ee1b58
RDX: 0000000000000000 RSI: ffffffff8bccef00 RDI: ffffffff9014f190
RBP: ffff888057ee1bb0 R08: 0000000000000000 R09: ffff8880355ebd00
R10: ffffffff8bccec80 R11: ffffed100afdc36d R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888057ee1b58 R15: 1ffff1100afdc36c
FS: 00007fe4bcd286c0(0000) GS:ffff88812545d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f35e7be7158 CR3: 000000002f141000 CR4: 0000000000350ef0
Call Trace:
<TASK>
inode_unlock include/linux/fs.h:1038 [inline]
vfs_remove_acl+0x763/0x830 fs/posix_acl.c:1251
removexattr fs/xattr.c:1009 [inline]
filename_removexattr fs/xattr.c:1038 [inline]
path_removexattrat+0x51a/0x750 fs/xattr.c:1071
__do_sys_lremovexattr fs/xattr.c:1089 [inline]
__se_sys_lremovexattr fs/xattr.c:1086 [inline]
__x64_sys_lremovexattr+0x65/0x80 fs/xattr.c:1086
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe4bbd9c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4bcd28028 EFLAGS: 00000246 ORIG_RAX: 00000000000000c6
RAX: ffffffffffffffda RBX: 00007fe4bc015fa0 RCX: 00007fe4bbd9c799
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000080
RBP: 00007fe4bbe32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe4bc016038 R14: 00007fe4bc015fa0 R15: 00007ffeeba43088
</TASK>
----------------
Code disassembly (best guess):
0: cc int3
1: 8b 49 c7 mov -0x39(%rcx),%ecx
4: c2 a0 ec ret $0xeca0
7: cc int3
8: 8b 4c 0f 44 mov 0x44(%rdi,%rcx,1),%ecx
c: d0 48 8b rorb $1,-0x75(%rax)
f: 7c 24 jl 0x35
11: 08 48 c7 or %cl,-0x39(%rax)
14: c6 00 ef movb $0xef,(%rax)
17: cc int3
18: 8b 48 8b mov -0x75(%rax),%ecx
1b: 14 24 adc $0x24,%al
1d: 4c 89 f1 mov %r14,%rcx
20: 4d 89 e0 mov %r12,%r8
23: 4c 8b 4c 24 10 mov 0x10(%rsp),%r9
28: 41 52 push %r10
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 48 83 c4 08 add $0x8,%rsp
33: e8 2a 5f 0a 03 call 0x30a5f62
38: e9 67 fd ff ff jmp 0xfffffda4
3d: 48 rex.W
3e: c7 .byte 0xc7
3f: c1 .byte 0xc1


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