syzbot


WARNING in f2fs_unlink

Status: upstream: reported C repro on 2025/02/10 09:12
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+27489c6642fc3831fdbd@syzkaller.appspotmail.com
First crash: 151d, last: 40d
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: WARNING in f2fs_unlink (log)
Repro: C syz .config
  
Bug presence (3)
Date Name Commit Repro Result
2025/04/26 linux-6.1.y (ToT) 535ec20c5027 C [report] WARNING in f2fs_unlink
2025/03/11 upstream (ToT) 4d872d51bc9d C [report] WARNING in f2fs_unlink
2025/04/26 upstream (ToT) f1a3944c860b C Didn't crash
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in f2fs_unlink f2fs -1 C done 215 106d 231d 28/29 fixed on 2025/06/10 16:19
Fix bisection attempts (3)
Created Duration User Patch Repo Result
2025/05/28 15:54 3h37m fix candidate upstream OK (0) job log
2025/04/17 04:22 2h40m bisect fix linux-6.1.y OK (0) job log log
2025/03/13 23:59 2h51m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
F2FS-fs (loop0): invalid namelen(0), ino:8, run fsck to fix.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4247 at fs/inode.c:332 drop_nlink+0xbb/0x100 fs/inode.c:332
Modules linked in:
CPU: 1 PID: 4247 Comm: syz-executor372 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:drop_nlink+0xbb/0x100 fs/inode.c:332
Code: 48 8b 1b 48 8d bb c0 07 00 00 be 08 00 00 00 e8 6b 7d eb ff f0 48 ff 83 c0 07 00 00 5b 41 5c 41 5e 41 5f 5d c3 e8 b5 05 9a ff <0f> 0b eb 88 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 62 ff ff ff 4c
RSP: 0018:ffffc90003c27c58 EFLAGS: 00010293
RAX: ffffffff81e6d15b RBX: ffff888073f311c0 RCX: ffff8880797d9dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff2117062
R10: fffffbfff2117062 R11: 1ffffffff2117061 R12: 1ffff1100e7e6241
R13: 00000000683ac93e R14: ffff888073f31208 R15: dffffc0000000000
FS:  0000555584550380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555584569778 CR3: 0000000027e03000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 f2fs_i_links_write fs/f2fs/f2fs.h:3044 [inline]
 f2fs_drop_nlink+0x125/0x3b0 fs/f2fs/dir.c:922
 f2fs_unlink+0x3d4/0x8c0 fs/f2fs/namei.c:562
 vfs_rmdir+0x36c/0x4d0 fs/namei.c:4191
 do_rmdir+0x288/0x5e0 fs/namei.c:4252
 __do_sys_rmdir fs/namei.c:4271 [inline]
 __se_sys_rmdir fs/namei.c:4269 [inline]
 __x64_sys_rmdir+0x45/0x50 fs/namei.c:4269
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc5788eac87
Code: 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 54 00 00 00 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:00007ffdad6ad988 EFLAGS: 00000207 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc5788eac87
RDX: 0000000000008890 RSI: 0000000000000000 RDI: 00007ffdad6aeb30
RBP: 0000000000000065 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffdad6aeb30
R13: 0000555584561740 R14: 431bde82d7b634db R15: 00007ffdad6b0cb0
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/31 09:18 linux-6.1.y da3c5173c55f 3d2f584d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan WARNING in f2fs_unlink
2025/02/10 09:54 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan WARNING in f2fs_unlink
2025/02/10 09:32 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan WARNING in f2fs_unlink
2025/06/01 19:01 linux-6.1.y da3c5173c55f 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in f2fs_unlink
2025/05/31 07:05 linux-6.1.y da3c5173c55f 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in f2fs_unlink
2025/02/10 09:13 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in f2fs_unlink
2025/02/10 09:11 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in f2fs_unlink
* Struck through repros no longer work on HEAD.