syzbot
general protection fault in jbd2_journal_file_inode
Status:
upstream: reported C repro on 2026/11/12 15:14
Reported-by: syzbot+b8e5d51daf3946929dd9@syzkaller.appspotmail.com
First crash: 1d07h, last: 12h58m
Sample crash report:
EXT4-fs (loop0): Using encoding defined by superblock: utf8-12.1.0 with flags 0x0
EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: init_itable,,errors=continue. Quota mode: journalled.
general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 1 PID: 303 Comm: syz-executor884 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:2700
Code: 03 48 89 45 c0 48 8d b8 80 04 00 00 48 89 7d b8 e8 42 de c7 02 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 32 9c bb ff 4d 09 66 28 4d 8d 66 38 4d 89 e7
RSP: 0018:ffffc90000957718 EFLAGS: 00010206
RAX: 0000000000000005 RBX: ffff8881208413c0 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000028
RBP: ffffc90000957760 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200012aed4 R12: 0000000000000006
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff11024108278
FS: 00005555809673c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056074e56a428 CR3: 000000011d133000 CR4: 00000000003506a0
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:2744
ext4_jbd2_inode_add_write fs/ext4/ext4_jbd2.h:424 [inline]
ext4_map_blocks+0x1167/0x1a50 fs/ext4/inode.c:764
ext4_convert_inline_data_nolock+0x435/0xcd0 fs/ext4/inline.c:1286
ext4_convert_inline_data+0x470/0x5b0 fs/ext4/inline.c:2129
ext4_setattr+0xdc7/0x1b10 fs/ext4/inode.c:5555
notify_change+0xc30/0xf40 fs/attr.c:505
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+0x212/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:77
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5f76cdb2e9
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:00007fff4b5fe3e8 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f5f76cdb2e9
RDX: 00007fff4b5fe270 RSI: 0000000002fffffd RDI: 00002000000033c0
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff4b5fe518
R13: 0000000000000002 R14: 00007f5f76d66c80 R15: 0000000000000002
</TASK>
Modules linked in:
---[ end trace d1a5ba8d6dd0d721 ]---
RIP: 0010:jbd2_journal_file_inode+0x143/0x580 fs/jbd2/transaction.c:2700
Code: 03 48 89 45 c0 48 8d b8 80 04 00 00 48 89 7d b8 e8 42 de c7 02 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 32 9c bb ff 4d 09 66 28 4d 8d 66 38 4d 89 e7
RSP: 0018:ffffc90000957718 EFLAGS: 00010206
RAX: 0000000000000005 RBX: ffff8881208413c0 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000028
RBP: ffffc90000957760 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200012aed4 R12: 0000000000000006
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff11024108278
FS: 00005555809673c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056074e56a428 CR3: 000000011d133000 CR4: 00000000003506a0
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 42 de c7 02 call 0x2c7de57
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 32 9c bb ff call 0xffbb9c67
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.