syzbot


WARNING in bfs_get_block

Status: upstream: reported C repro on 2026/04/24 05:14
Reported-by: syzbot+f719c54d9fe65474cc4d@syzkaller.appspotmail.com
First crash: 3d07h, last: 22h21m
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in bfs_get_block bfs -1 C error 95 6h34m 28d 0/29 upstream: reported C repro on 2026/03/30 05:05

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 6311 at fs/buffer.c:1188 mark_buffer_dirty+0x2bb/0x4c0 fs/buffer.c:1188
Modules linked in:
CPU: 1 PID: 6311 Comm: syz.2.177 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:mark_buffer_dirty+0x2bb/0x4c0 fs/buffer.c:1188
Code: 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 9f 9a fc ff e8 5a b6 88 ff 48 89 df 5b 41 5c 41 5e 41 5f 5d e9 ea 08 e8 ff e8 45 b6 88 ff <0f> 0b e9 84 fd ff ff e8 39 b6 88 ff 0f 0b e9 b0 fd ff ff e8 2d b6
RSP: 0018:ffffc90004aff850 EFLAGS: 00010293
RAX: ffffffff81fe6bbb RBX: ffff88805c4323a0 RCX: ffff888022a60000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff88805c038a01 R08: ffff88805c4323a7 R09: 1ffff1100b886474
R10: dffffc0000000000 R11: ffffed100b886475 R12: ffff88805ef7e160
R13: 0000000000000200 R14: ffff88806c0d6000 R15: 000000000000000f
FS:  00007fcb803c06c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000030adb000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 bfs_move_block fs/bfs/file.c:43 [inline]
 bfs_move_blocks fs/bfs/file.c:56 [inline]
 bfs_get_block+0x593/0xa50 fs/bfs/file.c:125
 __block_write_begin_int+0x57f/0x1af0 fs/buffer.c:2124
 __block_write_begin fs/buffer.c:2173 [inline]
 block_write_begin+0x9a/0x1e0 fs/buffer.c:2234
 bfs_write_begin+0x35/0xd0 fs/bfs/file.c:177
 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4036
 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4157
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x46c/0x990 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __x64_sys_pwrite64+0x19b/0x230 fs/read_write.c:706
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcb7f59cdd9
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:00007fcb803c0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fcb7f815fa0 RCX: 00007fcb7f59cdd9
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000005
RBP: 00007fcb7f632d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb7f816038 R14: 00007fcb7f815fa0 R15: 00007fff31fe2588
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/26 09:42 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan WARNING in bfs_get_block
2026/04/26 05:06 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan WARNING in bfs_get_block
2026/04/26 14:48 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan WARNING in bfs_get_block
2026/04/26 07:58 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan WARNING in bfs_get_block
2026/04/25 21:52 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan WARNING in bfs_get_block
2026/04/24 05:13 linux-6.6.y 9760bf04666d 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in bfs_get_block
* Struck through repros no longer work on HEAD.