syzbot


general protection fault in __ext4_journal_get_write_access (4)

Status: upstream: reported on 2025/11/26 15:43
Reported-by: syzbot+c890c084a63d534ab61b@syzkaller.appspotmail.com
First crash: 5d23h, last: 5d23h
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 general protection fault in __ext4_journal_get_write_access (2) 2 1 300d 300d 0/3 auto-obsoleted due to no activity on 2025/05/16 06:11
upstream general protection fault in __ext4_journal_get_write_access fuse ext4 2 C done done 7 1848d 1897d 22/29 fixed on 2022/11/15 22:34
linux-6.1 general protection fault in __ext4_journal_get_write_access 2 2 443d 446d 0/3 auto-obsoleted due to no activity on 2024/12/24 15:34
android-6-1 general protection fault in __ext4_journal_get_write_access missing-backport origin:lts 2 C 91 21d 56d 0/2 upstream: reported C repro on 2025/10/06 16:02
linux-6.1 general protection fault in __ext4_journal_get_write_access (3) 2 1 134d 134d 0/3 auto-obsoleted due to no activity on 2025/10/29 07:49

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 0 PID: 4455 Comm: ext4lazyinit Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__ext4_journal_get_write_access+0xc6/0x6d0 fs/ext4/ext4_jbd2.c:231
Code: 31 c0 49 8d 5f 30 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 f8 86 b5 ff 48 8b 1b 48 83 c3 38 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 db 86 b5 ff 4c 8b 23 4d 85 e4 4c
RSP: 0018:ffffc90004387ba0 EFLAGS: 00010202
RAX: 0000000000000007 RBX: 0000000000000038 RCX: d662d970f4920300
RDX: ffff88802a87bb80 RSI: ffffffff8a8c1700 RDI: ffffffff8adef760
RBP: ffffc90004387c70 R08: ffff88805555bae0 R09: 0000000000000001
R10: ffffed100aa99835 R11: 1ffff1100aa99834 R12: 1ffff1100ed884cf
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88805555bae0
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f23d61b42f8 CR3: 000000005d30f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_init_inode_table+0x3fa/0x7b0 fs/ext4/ialloc.c:1598
 ext4_run_li_request fs/ext4/super.c:3682 [inline]
 ext4_lazyinit_thread+0xba4/0x1800 fs/ext4/super.c:3773
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__ext4_journal_get_write_access+0xc6/0x6d0 fs/ext4/ext4_jbd2.c:231
Code: 31 c0 49 8d 5f 30 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 f8 86 b5 ff 48 8b 1b 48 83 c3 38 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 db 86 b5 ff 4c 8b 23 4d 85 e4 4c
RSP: 0018:ffffc90004387ba0 EFLAGS: 00010202
RAX: 0000000000000007 RBX: 0000000000000038 RCX: d662d970f4920300
RDX: ffff88802a87bb80 RSI: ffffffff8a8c1700 RDI: ffffffff8adef760
RBP: ffffc90004387c70 R08: ffff88805555bae0 R09: 0000000000000001
R10: ffffed100aa99835 R11: 1ffff1100aa99834 R12: 1ffff1100ed884cf
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88805555bae0
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33f75b7198 CR3: 000000005d30f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	31 c0                	xor    %eax,%eax
   2:	49 8d 5f 30          	lea    0x30(%r15),%rbx
   6:	48 89 d8             	mov    %rbx,%rax
   9:	48 c1 e8 03          	shr    $0x3,%rax
   d:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  12:	74 08                	je     0x1c
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 f8 86 b5 ff       	call   0xffb58714
  1c:	48 8b 1b             	mov    (%rbx),%rbx
  1f:	48 83 c3 38          	add    $0x38,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 db 86 b5 ff       	call   0xffb58714
  39:	4c 8b 23             	mov    (%rbx),%r12
  3c:	4d 85 e4             	test   %r12,%r12
  3f:	4c                   	rex.WR

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/26 15:43 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in __ext4_journal_get_write_access
* Struck through repros no longer work on HEAD.