syzbot
linux-next test error: general protection fault in __bh_submit
Status:
upstream: reported on 2026/09/05 16:35
Subsystems:
ext4
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+5a7a23af225c215902e7@syzkaller.appspotmail.com
First crash: 4d06h, last: 3d08h
Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 4945 Comm: jbd2/sda1-8 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:const_folio_flags include/linux/page-flags.h:345 [inline]
RIP: 0010:folio_test_dropbehind include/linux/page-flags.h:600 [inline]
RIP: 0010:__bh_submit+0x22d/0x8d0 fs/buffer.c:1109
Code: c1 e8 03 48 89 44 24 18 42 80 3c 20 00 74 08 48 89 df e8 26 f6 d7 ff 48 89 5c 24 28 48 8b 1b 4c 8d 7b 08 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 04 f6 d7 ff 4d 8b 3f 4c 89 fe 48
RSP: 0018:ffffc9001016f868 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff84b96ff9
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888075a7a660
RBP: 0000000000009801 R08: ffff888075a7a6bf R09: 1ffff1100eb4f4d7
R10: dffffc0000000000 R11: ffffed100eb4f4d8 R12: dffffc0000000000
R13: ffff888075a7a640 R14: ffff8880123a17e0 R15: 0000000000000008
FS: 0000000000000000(0000) GS:ffff888124ccb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe1ee627da0 CR3: 0000000074fa8000 CR4: 00000000003526f0
Call Trace:
<TASK>
jbd2_journal_commit_transaction+0x22a9/0x5cd0 fs/jbd2/commit.c:751
kjournald2+0x3bc/0x750 fs/jbd2/journal.c:200
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:const_folio_flags include/linux/page-flags.h:345 [inline]
RIP: 0010:folio_test_dropbehind include/linux/page-flags.h:600 [inline]
RIP: 0010:__bh_submit+0x22d/0x8d0 fs/buffer.c:1109
Code: c1 e8 03 48 89 44 24 18 42 80 3c 20 00 74 08 48 89 df e8 26 f6 d7 ff 48 89 5c 24 28 48 8b 1b 4c 8d 7b 08 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 04 f6 d7 ff 4d 8b 3f 4c 89 fe 48
RSP: 0018:ffffc9001016f868 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff84b96ff9
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888075a7a660
RBP: 0000000000009801 R08: ffff888075a7a6bf R09: 1ffff1100eb4f4d7
R10: dffffc0000000000 R11: ffffed100eb4f4d8 R12: dffffc0000000000
R13: ffff888075a7a640 R14: ffff8880123a17e0 R15: 0000000000000008
FS: 0000000000000000(0000) GS:ffff888124dcb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87c696cf80 CR3: 000000000eb48000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: c1 e8 03 shr $0x3,%eax
3: 48 89 44 24 18 mov %rax,0x18(%rsp)
8: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1)
d: 74 08 je 0x17
f: 48 89 df mov %rbx,%rdi
12: e8 26 f6 d7 ff call 0xffd7f63d
17: 48 89 5c 24 28 mov %rbx,0x28(%rsp)
1c: 48 8b 1b mov (%rbx),%rbx
1f: 4c 8d 7b 08 lea 0x8(%rbx),%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 ff mov %r15,%rdi
34: e8 04 f6 d7 ff call 0xffd7f63d
39: 4d 8b 3f mov (%r15),%r15
3c: 4c 89 fe mov %r15,%rsi
3f: 48 rex.W
* Struck through repros no longer work on HEAD.