syzbot


WARNING in lookup_slow (4)

Status: moderation: reported on 2025/05/26 09:57
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+2b8d9d5c6bae92cffb1d@syzkaller.appspotmail.com
First crash: 31d, last: 3d18h
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in lookup_slow (2) 1 599d 599d 0/3 auto-obsoleted due to no activity on 2024/02/09 08:58
upstream WARNING in lookup_slow (2) fs 8 374d 405d 0/29 auto-obsoleted due to no activity on 2024/09/12 01:16
linux-6.1 WARNING in lookup_slow origin:upstream missing-backport C inconclusive 8 116d 568d 0/3 upstream: reported C repro on 2023/12/02 22:03
upstream WARNING in lookup_slow (3) fs 1 181d 177d 0/29 auto-obsoleted due to no activity on 2025/02/21 12:31
linux-5.15 WARNING in lookup_slow (3) origin:lts-only C error 7 40d 449d 0/3 upstream: reported C repro on 2024/03/30 12:27
upstream WARNING in lookup_slow ntfs3 C error inconclusive 34 516d 916d 0/29 auto-obsoleted due to no activity on 2024/05/02 19:30
linux-5.15 WARNING in lookup_slow 1 759d 759d 0/3 auto-obsoleted due to no activity on 2023/09/02 18:27

Sample crash report:
loop0: detected capacity change from 0 to 32768
gfs2: fsid=syz:syz: Trying to join cluster "lock_nolock", "syz:syz"
gfs2: fsid=syz:syz: Now mounting FS (format 1801)...
gfs2: fsid=syz:syz.0: journal 0 mapped with 1 extents in 0ms
gfs2: fsid=syz:syz.0: first mount done, others may mount
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem)): count = 0x101, magic = 0xffff888052c6db98, owner = 0x0, curr 0xffff888000cca440, list not empty
WARNING: CPU: 0 PID: 5325 at kernel/locking/rwsem.c:1341 __up_read+0x5f5/0x680 kernel/locking/rwsem.c:1341
Modules linked in:
CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 Not tainted 6.16.0-rc2-syzkaller-00082-gfb4d33ab452e #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__up_read+0x5f5/0x680 kernel/locking/rwsem.c:1341
Code: 44 d0 48 c7 c7 c0 f0 8a 8b 48 c7 c6 60 f1 8a 8b 4c 89 ea 48 8b 4c 24 08 4d 89 e0 4d 89 f1 41 52 e8 f0 3f e6 ff 48 83 c4 08 90 <0f> 0b 90 90 e9 72 fb ff ff 48 c7 c1 34 3f a1 8f 80 e1 07 80 c1 03
RSP: 0018:ffffc9000d437900 EFLAGS: 00010296
RAX: 0634ebded6490800 RBX: ffff888052c6db98 RCX: ffff888000cca440
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc9000d4379b8 R08: ffff88801fc24293 R09: 1ffff11003f84852
R10: dffffc0000000000 R11: ffffed1003f84853 R12: 0000000000000000
R13: 0000000000000101 R14: ffff888000cca440 R15: ffff888052c6dbf0
FS:  00007fd7c6f8e6c0(0000) GS:ffff88808d251000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7c6f4bfc8 CR3: 0000000041b62000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 inode_unlock_shared include/linux/fs.h:894 [inline]
 lookup_slow+0x5e/0x70 fs/namei.c:1835
 walk_component fs/namei.c:2138 [inline]
 link_path_walk+0x935/0xea0 fs/namei.c:2506
 path_parentat fs/namei.c:2710 [inline]
 __filename_parentat+0x246/0x670 fs/namei.c:2734
 filename_parentat fs/namei.c:2752 [inline]
 do_renameat2+0x255/0xc50 fs/namei.c:5209
 __do_sys_renameat2 fs/namei.c:5320 [inline]
 __se_sys_renameat2 fs/namei.c:5317 [inline]
 __x64_sys_renameat2+0xce/0xe0 fs/namei.c:5317
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd7c618e929
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:00007fd7c6f8e038 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007fd7c63b5fa0 RCX: 00007fd7c618e929
RDX: ffffffffffffff9c RSI: 0000200000000580 RDI: ffffffffffffff9c
RBP: 00007fd7c6210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000005c0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd7c63b5fa0 R15: 00007ffe52403008
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/19 09:02 upstream fb4d33ab452e ed3e87f7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/05/30 12:38 upstream f66bc387efbe 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/05/22 09:52 upstream d608703fcdd9 0919b50b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
* Struck through repros no longer work on HEAD.