syzbot


kernel BUG in bdev_getblk

Status: moderation: reported on 2026/04/10 14:30
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+bd20cfddc4d4ee3b6730@syzkaller.appspotmail.com
First crash: 9d12h, last: 9d12h

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/buffer.c:1579!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 3 UID: 0 PID: 19369 Comm: syz.6.3835 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:folio_set_bh fs/buffer.c:1579 [inline]
RIP: 0010:folio_set_bh fs/buffer.c:1575 [inline]
RIP: 0010:folio_alloc_buffers+0x68e/0x8f0 fs/buffer.c:943
Code: 02 00 00 4d 8b 64 24 10 e9 a3 fa ff ff e8 fa 45 6a ff 48 c7 c6 e0 21 c6 8b 48 89 df e8 ab 57 b7 ff 90 0f 0b e8 e3 45 6a ff 90 <0f> 0b e8 db 45 6a ff 48 bd 00 00 00 00 00 fc ff df 4d 85 ff 75 05
RSP: 0018:ffffc90004537a98 EFLAGS: 00010283
RAX: 000000000000199d RBX: ffffea0001666f80 RCX: ffffc900079c3000
RDX: 0000000000080000 RSI: ffffffff829eb17d RDI: ffff88802a18c980
RBP: ffff88812802d0e8 R08: 0000000000000006 R09: 0000000000001000
R10: 0000000000001000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffea0001666f88 R14: 0000000000001000 R15: 0000000000001000
FS:  00007efe89c146c0(0000) GS:ffff8880d6639000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efe88e4edd5 CR3: 0000000062bc2000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 grow_dev_folio fs/buffer.c:1072 [inline]
 grow_buffers fs/buffer.c:1113 [inline]
 __getblk_slow fs/buffer.c:1131 [inline]
 bdev_getblk+0x2fb/0x6a0 fs/buffer.c:1458
 __bread_gfp+0x86/0x3c0 fs/buffer.c:1512
 sb_bread include/linux/buffer_head.h:346 [inline]
 qnx4_fill_super+0x1f8/0x760 fs/qnx4/inode.c:216
 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1694
 vfs_get_tree+0x92/0x320 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3763 [inline]
 do_new_mount fs/namespace.c:3839 [inline]
 path_mount+0x7d0/0x23d0 fs/namespace.c:4159
 do_mount fs/namespace.c:4172 [inline]
 __do_sys_mount fs/namespace.c:4361 [inline]
 __se_sys_mount fs/namespace.c:4338 [inline]
 __x64_sys_mount+0x293/0x310 fs/namespace.c:4338
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe88d9c819
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:00007efe89c14028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007efe89015fa0 RCX: 00007efe88d9c819
RDX: 00002000000001c0 RSI: 0000200000000000 RDI: 0000200000000040
RBP: 00007efe88e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000208004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe89016038 R14: 00007efe89015fa0 R15: 00007ffe22f8f3b8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:folio_set_bh fs/buffer.c:1579 [inline]
RIP: 0010:folio_set_bh fs/buffer.c:1575 [inline]
RIP: 0010:folio_alloc_buffers+0x68e/0x8f0 fs/buffer.c:943
Code: 02 00 00 4d 8b 64 24 10 e9 a3 fa ff ff e8 fa 45 6a ff 48 c7 c6 e0 21 c6 8b 48 89 df e8 ab 57 b7 ff 90 0f 0b e8 e3 45 6a ff 90 <0f> 0b e8 db 45 6a ff 48 bd 00 00 00 00 00 fc ff df 4d 85 ff 75 05
RSP: 0018:ffffc90004537a98 EFLAGS: 00010283
RAX: 000000000000199d RBX: ffffea0001666f80 RCX: ffffc900079c3000
RDX: 0000000000080000 RSI: ffffffff829eb17d RDI: ffff88802a18c980
RBP: ffff88812802d0e8 R08: 0000000000000006 R09: 0000000000001000
R10: 0000000000001000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffea0001666f88 R14: 0000000000001000 R15: 0000000000001000
FS:  00007efe89c146c0(0000) GS:ffff8880d6339000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055db550c6000 CR3: 0000000062bc2000 CR4: 0000000000352ef0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/06 14:19 upstream 591cd656a1bf 4440e7c2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in bdev_getblk
* Struck through repros no longer work on HEAD.