syzbot


WARNING in bfs_get_block

Status: upstream: reported on 2026/05/07 22:51
Reported-by: syzbot+615f4f94914be8224a24@syzkaller.appspotmail.com
First crash: 4d06h, last: 4d06h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in bfs_get_block bfs -1 C error 147 1d18h 43d 0/29 upstream: reported C repro on 2026/03/30 05:05
linux-6.6 WARNING in bfs_get_block -1 C 6 15d 17d 0/2 upstream: reported C repro on 2026/04/24 05:14

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 14043 at fs/buffer.c:1081 mark_buffer_dirty+0x383/0x7a0 fs/buffer.c:1081
Modules linked in:
CPU: 1 PID: 14043 Comm: syz.3.1891 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:mark_buffer_dirty+0x383/0x7a0 fs/buffer.c:1081
Code: 83 71 e2 ff 49 8b 3f be 04 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 fc a9 fc ff e8 27 65 91 ff e9 43 ff ff ff e8 1d 65 91 ff <0f> 0b e9 ba fc ff ff e8 11 65 91 ff 0f 0b e9 00 fd ff ff e8 05 65
RSP: 0018:ffffc90003fd7808 EFLAGS: 00010283
RAX: ffffffff81f11033 RBX: ffff888073a57cb0 RCX: 0000000000080000
RDX: ffffc9000eab9000 RSI: 00000000000060f7 RDI: 00000000000060f8
RBP: ffff888054bde601 R08: ffff888073a57cb7 R09: 1ffff1100e74af96
R10: dffffc0000000000 R11: ffffed100e74af97 R12: ffff888053a68160
R13: 0000000000000200 R14: ffff8880514e7800 R15: 000000000000000a
FS:  00007f832269b6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8fedfea4c0 CR3: 00000000644ee000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bfs_move_block fs/bfs/file.c:43 [inline]
 bfs_move_blocks fs/bfs/file.c:56 [inline]
 bfs_get_block+0x58f/0xa50 fs/bfs/file.c:125
 __block_write_begin_int+0x55d/0x1a80 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x96/0x1e0 fs/buffer.c:2102
 bfs_write_begin+0x31/0xd0 fs/bfs/file.c:177
 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4b1/0xa30 fs/read_write.c:584
 ksys_write+0x14c/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f832179cdd9
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:00007f832269b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8321a15fa0 RCX: 00007f832179cdd9
RDX: 000000000000fecc RSI: 00002000000008c0 RDI: 0000000000000007
RBP: 00007f8321832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8321a16038 R14: 00007f8321a15fa0 R15: 00007ffd15b0baf8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/07 22:50 linux-6.1.y 4931e0e1673d cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in bfs_get_block
* Struck through repros no longer work on HEAD.