syzbot


kernel BUG in bdev_getblk

Status: moderation: reported on 2026/04/10 14:30
Subsystems: fs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+bd20cfddc4d4ee3b6730@syzkaller.appspotmail.com
First crash: 55d, last: 2d02h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
b296375b-0984-4251-b793-2d4302c3aabf assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ kernel BUG in bdev_getblk 2026/05/20 05:59 2026/05/20 05:59 2026/05/20 06:40 0909d65fc692e54fa1900b68b476e89207bc7f34

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/buffer.c:1479!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 1198 Comm: syz.5.7404 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:1479 [inline]
RIP: 0010:folio_set_bh fs/buffer.c:1475 [inline]
RIP: 0010:folio_alloc_buffers+0x4b5/0x8e0 fs/buffer.c:849
Code: 18 48 89 83 00 17 00 00 e9 d1 fb ff ff e8 b3 79 69 ff 48 c7 c6 40 78 c6 8b 48 89 ef e8 d4 b1 b8 ff 90 0f 0b e8 9c 79 69 ff 90 <0f> 0b e8 94 79 69 ff 48 bd 00 00 00 00 00 fc ff df 4d 85 f6 75 05
RSP: 0018:ffffc90004abfa90 EFLAGS: 00010283
RAX: 0000000000001a1a RBX: ffff888057a5e910 RCX: ffffc9003690f000
RDX: 0000000000080000 RSI: ffffffff829f2784 RDI: ffff88806226a540
RBP: ffffea000194f540 R08: 0000000000000006 R09: 0000000000001000
R10: 0000000000001000 R11: ffff88801cef2100 R12: dffffc0000000000
R13: 0000000000001000 R14: 0000000000001000 R15: 0000000000000000
FS:  00007f3520bf66c0(0000) GS:ffff8880d6386000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3ae534 CR3: 000000004d5d7000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 grow_dev_folio fs/buffer.c:979 [inline]
 grow_buffers fs/buffer.c:1020 [inline]
 __getblk_slow fs/buffer.c:1038 [inline]
 bdev_getblk+0x2fb/0x6a0 fs/buffer.c:1358
 __bread_gfp+0x86/0x3c0 fs/buffer.c:1412
 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:3758 [inline]
 do_new_mount fs/namespace.c:3834 [inline]
 path_mount+0x7d0/0x23d0 fs/namespace.c:4154
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount fs/namespace.c:4360 [inline]
 __x64_sys_mount+0x293/0x310 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f352299ce59
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:00007f3520bf6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f3522c15fa0 RCX: 00007f352299ce59
RDX: 00002000000001c0 RSI: 0000200000000000 RDI: 0000200000000040
RBP: 00007f3522a32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000208004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3522c16038 R14: 00007f3522c15fa0 R15: 00007fffa3279398
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:folio_set_bh fs/buffer.c:1479 [inline]
RIP: 0010:folio_set_bh fs/buffer.c:1475 [inline]
RIP: 0010:folio_alloc_buffers+0x4b5/0x8e0 fs/buffer.c:849
Code: 18 48 89 83 00 17 00 00 e9 d1 fb ff ff e8 b3 79 69 ff 48 c7 c6 40 78 c6 8b 48 89 ef e8 d4 b1 b8 ff 90 0f 0b e8 9c 79 69 ff 90 <0f> 0b e8 94 79 69 ff 48 bd 00 00 00 00 00 fc ff df 4d 85 f6 75 05
RSP: 0018:ffffc90004abfa90 EFLAGS: 00010283
RAX: 0000000000001a1a RBX: ffff888057a5e910 RCX: ffffc9003690f000
RDX: 0000000000080000 RSI: ffffffff829f2784 RDI: ffff88806226a540
RBP: ffffea000194f540 R08: 0000000000000006 R09: 0000000000001000
R10: 0000000000001000 R11: ffff88801cef2100 R12: dffffc0000000000
R13: 0000000000001000 R14: 0000000000001000 R15: 0000000000000000
FS:  00007f3520bf66c0(0000) GS:ffff8880d6386000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005603ba301da8 CR3: 000000004d5d7000 CR4: 0000000000352ef0

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/29 17:37 upstream 8fde5d1d47f6 6b4a8443 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in bdev_getblk
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.