syzbot


kernel BUG in f2fs_allocate_data_block

Status: upstream: reported C repro on 2025/06/16 20:16
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+fd1280572f6ac45a8a80@syzkaller.appspotmail.com
First crash: 302d, last: 9h26m
Bug presence (2)
Date Name Commit Repro Result
2025/06/22 linux-6.6.y (ToT) 6282921b6825 C [report] kernel BUG in f2fs_allocate_data_block
2025/06/22 upstream (ToT) 739a6c93cc75 C Didn't crash
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/09/15 11:56 1h48m fix candidate upstream OK (0) job log

Sample crash report:
F2FS-fs (loop0): invalid crc value
F2FS-fs (loop0): Found nat_bits in checkpoint
F2FS-fs (loop0): Start checkpoint disabled!
F2FS-fs (loop0): Mounted with checkpoint version = 48b305e6
------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.c:3481!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5926 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:f2fs_allocate_data_block+0x3f78/0x3fc0 fs/f2fs/segment.c:3481
Code: 20 fe 48 8b 54 24 30 e9 88 eb ff ff e8 b1 5b c9 fd 48 c7 c7 10 c4 2f 8d 4c 89 f6 e8 22 fb 95 00 e9 a4 eb ff ff e8 98 5b c9 fd <0f> 0b e8 91 5b c9 fd 0f 0b e8 8a 5b c9 fd 0f 0b e8 83 5b c9 fd 0f
RSP: 0018:ffffc900033e7410 EFLAGS: 00010293
RAX: ffffffff83bc4f68 RBX: 0000000000000200 RCX: ffff88802aac8000
RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000200
RBP: 0000000000000200 R08: ffff888024eb045f R09: 1ffff110049d608b
R10: dffffc0000000000 R11: ffffed10049d608c R12: 1ffff9200067cef8
R13: 0000000000000000 R14: 0000000000001a00 R15: dffffc0000000000
FS:  000055555a35a500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34263fff CR3: 000000002c279000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 __allocate_data_block fs/f2fs/data.c:1421 [inline]
 f2fs_map_blocks+0x12dd/0x3da0 fs/f2fs/data.c:1604
 f2fs_expand_inode_data+0x65e/0xa10 fs/f2fs/file.c:1851
 f2fs_fallocate+0x416/0x8a0 fs/f2fs/file.c:1954
 vfs_fallocate+0x58e/0x700 fs/open.c:324
 ioctl_preallocate fs/ioctl.c:291 [inline]
 file_ioctl fs/ioctl.c:-1 [inline]
 do_vfs_ioctl+0x1935/0x1bb0 fs/ioctl.c:850
 __do_sys_ioctl fs/ioctl.c:869 [inline]
 __se_sys_ioctl+0x83/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f25b8d8f749
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:00007ffd508f7438 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f25b8fe5fa0 RCX: 00007f25b8d8f749
RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007f25b8e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f25b8fe5fa0 R14: 00007f25b8fe5fa0 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_allocate_data_block+0x3f78/0x3fc0 fs/f2fs/segment.c:3481
Code: 20 fe 48 8b 54 24 30 e9 88 eb ff ff e8 b1 5b c9 fd 48 c7 c7 10 c4 2f 8d 4c 89 f6 e8 22 fb 95 00 e9 a4 eb ff ff e8 98 5b c9 fd <0f> 0b e8 91 5b c9 fd 0f 0b e8 8a 5b c9 fd 0f 0b e8 83 5b c9 fd 0f
RSP: 0018:ffffc900033e7410 EFLAGS: 00010293
RAX: ffffffff83bc4f68 RBX: 0000000000000200 RCX: ffff88802aac8000
RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000200
RBP: 0000000000000200 R08: ffff888024eb045f R09: 1ffff110049d608b
R10: dffffc0000000000 R11: ffffed10049d608c R12: 1ffff9200067cef8
R13: 0000000000000000 R14: 0000000000001a00 R15: dffffc0000000000
FS:  000055555a35a500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb174558000 CR3: 000000002c279000 CR4: 00000000003506f0

Crashes (448):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/15 01:30 linux-6.6.y c596736dadab d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2025/09/30 07:24 linux-6.6.y 147338df3487 86341da6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2025/06/20 09:27 linux-6.6.y 6282921b6825 ed3e87f7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/15 10:31 linux-6.6.y 8cee53b8eaeb e2e976a8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/15 09:01 linux-6.6.y 8cee53b8eaeb e2e976a8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/13 21:13 linux-6.6.y 8cee53b8eaeb 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/09 14:41 linux-6.6.y 80de0a958133 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/08 12:49 linux-6.6.y 80de0a958133 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/08 09:45 linux-6.6.y 80de0a958133 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/08 09:39 linux-6.6.y 80de0a958133 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/06 08:06 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/05 00:16 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/03 17:02 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/03 08:18 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/01 19:26 linux-6.6.y c09fbcd31ae6 9a1f7828 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/01 19:26 linux-6.6.y c09fbcd31ae6 9a1f7828 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/01 07:06 linux-6.6.y c09fbcd31ae6 fb8b2c26 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/04/01 05:51 linux-6.6.y c09fbcd31ae6 fb8b2c26 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/30 16:28 linux-6.6.y c09fbcd31ae6 dcaebc52 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/29 22:40 linux-6.6.y c09fbcd31ae6 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/29 21:29 linux-6.6.y c09fbcd31ae6 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/28 21:01 linux-6.6.y c09fbcd31ae6 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/27 20:57 linux-6.6.y c09fbcd31ae6 74a13a23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/27 04:58 linux-6.6.y c09fbcd31ae6 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/27 04:56 linux-6.6.y c09fbcd31ae6 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/26 03:26 linux-6.6.y c09fbcd31ae6 c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/23 02:58 linux-6.6.y 4fc00fe35d46 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/12 20:30 linux-6.6.y 4fc00fe35d46 4efadf07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/12 19:21 linux-6.6.y 4fc00fe35d46 4efadf07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/12 07:45 linux-6.6.y 4fc00fe35d46 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/08 19:18 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/07 07:59 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/07 07:06 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/06 20:11 linux-6.6.y 4fc00fe35d46 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/06 06:04 linux-6.6.y 4fc00fe35d46 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/05 23:22 linux-6.6.y 4fc00fe35d46 d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/04 22:25 linux-6.6.y 682d8e2f892b e6b6b96b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/02 20:36 linux-6.6.y 7a137e9bfa0e b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/01 13:48 linux-6.6.y 7a137e9bfa0e 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/01 12:48 linux-6.6.y 7a137e9bfa0e 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/03/01 08:47 linux-6.6.y 7a137e9bfa0e 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/26 19:50 linux-6.6.y 7a137e9bfa0e ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/26 07:39 linux-6.6.y 7a137e9bfa0e e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/24 06:48 linux-6.6.y 7a137e9bfa0e 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/22 19:24 linux-6.6.y 7a137e9bfa0e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/22 11:05 linux-6.6.y 7a137e9bfa0e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/22 11:04 linux-6.6.y 7a137e9bfa0e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/22 02:41 linux-6.6.y 7a137e9bfa0e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/22 01:40 linux-6.6.y 7a137e9bfa0e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2026/02/20 17:41 linux-6.6.y 7a137e9bfa0e 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
2025/06/16 20:16 linux-6.6.y c2603c511feb d1716036 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in f2fs_allocate_data_block
* Struck through repros no longer work on HEAD.