syzbot


WARNING in vfs_remove_acl (2)

Status: moderation: reported on 2026/03/25 10:21
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+11ef4849e6440d660951@syzkaller.appspotmail.com
First crash: 8d20h, last: 2d20h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in vfs_remove_acl fs -1 2 178d 179d 0/29 auto-obsoleted due to no activity on 2025/12/01 11:23

Sample crash report:
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff88823be46ab8, owner = 0x0, curr 0xffff88802f678000, list empty
WARNING: kernel/locking/rwsem.c:1381 at __up_write kernel/locking/rwsem.c:1380 [inline], CPU#0: syz.3.322/7459
WARNING: kernel/locking/rwsem.c:1381 at up_write+0x2d6/0x410 kernel/locking/rwsem.c:1643, CPU#0: syz.3.322/7459
Modules linked in:
CPU: 0 UID: 0 PID: 7459 Comm: syz.3.322 Not tainted syzkaller #0 PREEMPT(full) 
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 3a a6 0a 03 e9 67 fd ff ff 48 c7 c1
RSP: 0018:ffffc9000499fbd0 EFLAGS: 00010246
RAX: ffffffff8bccec80 RBX: ffff88823be46ab8 RCX: ffff88823be46ab8
RDX: 0000000000000000 RSI: ffffffff8bccef00 RDI: ffffffff90150c90
RBP: ffff88823be46b10 R08: 0000000000000000 R09: ffff88802f678000
R10: ffffffff8bccec80 R11: ffffed10477c8d59 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88823be46ab8 R15: 1ffff110477c8d58
FS:  00007fd5502fd6c0(0000) GS:ffff88812545a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f16d35456b8 CR3: 0000000025f90000 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: 0033:0x7fd54f39c799
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:00007fd5502fd028 EFLAGS: 00000246 ORIG_RAX: 00000000000000c6
RAX: ffffffffffffffda RBX: 00007fd54f616090 RCX: 00007fd54f39c799
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000080
RBP: 00007fd54f432c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd54f616128 R14: 00007fd54f616090 R15: 00007fff4bbae518
 </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 3a a6 0a 03       	call   0x30aa672
  38:	e9 67 fd ff ff       	jmp    0xfffffda4
  3d:	48                   	rex.W
  3e:	c7                   	.byte 0xc7
  3f:	c1                   	.byte 0xc1

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/27 10:29 upstream 46b513250491 50cdcaa1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in vfs_remove_acl
2026/03/21 10:17 upstream c612261bedd6 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in vfs_remove_acl
* Struck through repros no longer work on HEAD.