syzbot
general protection fault in jbd2_journal_file_inode
Status:
upstream: reported C repro on 2026/11/12 15:25
Reported-by: syzbot+aa426bc45e95627702e0@syzkaller.appspotmail.com
First crash: 23h01m, last: 22h16m
Sample crash report:
EXT4-fs (loop0): mounted filesystem with ordered data mode. Quota mode: none.
general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 PID: 305 Comm: syz-executor413 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:jbd2_journal_file_inode+0x143/0x580 fs/jbd2/transaction.c:2698
Code: 03 48 89 45 c0 48 8d b8 80 04 00 00 48 89 7d b8 e8 82 f6 02 03 49 8d 7e 28 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 05 e8 42 e5 b7 ff 4d 09 66 28 4d 8d 66 38 4d 89 e7
RSP: 0018:ffffc90000e376f8 EFLAGS: 00010206
RAX: 0000000000000005 RBX: ffff88810c0903c0 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000028
RBP: ffffc90000e37740 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520001c6ed0 R12: 0000000000000006
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff11021812078
FS: 000055557ee653c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004100 CR3: 0000000122629000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
jbd2_journal_inode_ranged_write+0x34/0x40 fs/jbd2/transaction.c:2742
ext4_jbd2_inode_add_write fs/ext4/ext4_jbd2.h:424 [inline]
ext4_map_blocks+0x11c5/0x1a80 fs/ext4/inode.c:769
ext4_convert_inline_data_nolock+0x40a/0x9e0 fs/ext4/inline.c:1265
ext4_convert_inline_data+0x470/0x5b0 fs/ext4/inline.c:2127
ext4_setattr+0xf3c/0x1c80 fs/ext4/inode.c:5574
notify_change+0xd33/0x1030 fs/attr.c:499
do_truncate+0x1ac/0x240 fs/open.c:66
vfs_truncate+0x25b/0x2f0 fs/open.c:112
do_sys_truncate+0xf2/0x1c0 fs/open.c:135
__do_sys_truncate fs/open.c:147 [inline]
__se_sys_truncate fs/open.c:145 [inline]
__x64_sys_truncate+0x5b/0x70 fs/open.c:145
x64_sys_call+0x679/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:77
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: 0033:0x7fb403db22e9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc8a4895a8 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 0031656c69662f2e RCX: 00007fb403db22e9
RDX: 00007ffc8a489430 RSI: 0000000000009fe6 RDI: 0000200000004100
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8a4896d8
R13: 0000000000000002 R14: 00007fb403e3dc80 R15: 0000000000000002
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:jbd2_journal_file_inode+0x143/0x580 fs/jbd2/transaction.c:2698
Code: 03 48 89 45 c0 48 8d b8 80 04 00 00 48 89 7d b8 e8 82 f6 02 03 49 8d 7e 28 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 05 e8 42 e5 b7 ff 4d 09 66 28 4d 8d 66 38 4d 89 e7
RSP: 0018:ffffc90000e376f8 EFLAGS: 00010206
RAX: 0000000000000005 RBX: ffff88810c0903c0 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000028
RBP: ffffc90000e37740 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520001c6ed0 R12: 0000000000000006
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff11021812078
FS: 000055557ee653c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004100 CR3: 0000000122629000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 03 48 89 add -0x77(%rax),%ecx
3: 45 c0 48 8d b8 rex.RB rorb $0xb8,-0x73(%r8)
8: 80 04 00 00 addb $0x0,(%rax,%rax,1)
c: 48 89 7d b8 mov %rdi,-0x48(%rbp)
10: e8 82 f6 02 03 call 0x302f697
15: 49 8d 7e 28 lea 0x28(%r14),%rdi
19: 48 89 f8 mov %rdi,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
2e: 74 05 je 0x35
30: e8 42 e5 b7 ff call 0xffb7e577
35: 4d 09 66 28 or %r12,0x28(%r14)
39: 4d 8d 66 38 lea 0x38(%r14),%r12
3d: 4d 89 e7 mov %r12,%r15
* Struck through repros no longer work on HEAD.