syzbot

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: 431 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__ext4_journal_get_write_access+0xb0/0x6c0 fs/ext4/ext4_jbd2.c:231
Code: 8e ff 49 8d 5f 30 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 fe 8b d2 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 e1 8b d2 ff 4c 8b 23 4d 85 e4 4c
RSP: 0018:ffffc90000ea7740 EFLAGS: 00010202
RAX: 0000000000000007 RBX: 0000000000000038 RCX: ffff888118d96540
RDX: 0000000000000000 RSI: 0000000000000045 RDI: ffffffff8647269f
RBP: ffffc90000ea7810 R08: ffff888122d26bd0 R09: 0000000000000001
R10: ffffed10233e004b R11: 1ffff110233e004a R12: ffff888119f00000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888122d26bd0
FS:  000055556672f500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6da2f79000 CR3: 0000000130874000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_update_primary_sb fs/ext4/ioctl.c:67 [inline]
 ext4_update_superblocks_fn+0x256/0x1120 fs/ext4/ioctl.c:221
 ext4_update_overhead+0x146/0x180 fs/ext4/ioctl.c:1709
 ext4_fill_super+0x27a1/0x7970 fs/ext4/super.c:5674
 get_tree_bdev+0x444/0x680 fs/super.c:1368
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5685
 vfs_get_tree+0x9a/0x270 fs/super.c:1575
 do_new_mount+0x25a/0xa20 fs/namespace.c:3069
 path_mount+0x675/0x1010 fs/namespace.c:3399
 do_mount fs/namespace.c:3412 [inline]
 __do_sys_mount fs/namespace.c:3620 [inline]
 __se_sys_mount+0x318/0x380 fs/namespace.c:3597
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3597
 x64_sys_call+0x65d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe42c59066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb1474a08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdb1474a90 RCX: 00007fe42c59066a
RDX: 0000200000000140 RSI: 0000200000000040 RDI: 00007ffdb1474a50
RBP: 0000200000000140 R08: 00007ffdb1474a90 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000040
R13: 00007ffdb1474a50 R14: 00000000000005fc R15: 0000200000000080
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__ext4_journal_get_write_access+0xb0/0x6c0 fs/ext4/ext4_jbd2.c:231
Code: 8e ff 49 8d 5f 30 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 fe 8b d2 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 e1 8b d2 ff 4c 8b 23 4d 85 e4 4c
RSP: 0018:ffffc90000ea7740 EFLAGS: 00010202
RAX: 0000000000000007 RBX: 0000000000000038 RCX: ffff888118d96540
RDX: 0000000000000000 RSI: 0000000000000045 RDI: ffffffff8647269f
RBP: ffffc90000ea7810 R08: ffff888122d26bd0 R09: 0000000000000001
R10: ffffed10233e004b R11: 1ffff110233e004a R12: ffff888119f00000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888122d26bd0
FS:  000055556672f500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6da2f71000 CR3: 0000000130874000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	8e ff                	mov    %edi,%?
   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 fe 8b d2 ff       	call   0xffd28c1a
  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 e1 8b d2 ff       	call   0xffd28c1a
  39:	4c 8b 23             	mov    (%rbx),%r12
  3c:	4d 85 e4             	test   %r12,%r12
  3f:	4c                   	rex.WR