[v6.1] BUG: unable to handle kernel paging request in __ext4_journal_get_write_access

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 228da13e907e Linux 6.1.175
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1012d37a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=29caf4bae4b0566f
dashboard link: https://syzkaller.appspot.com/bug?extid=87233ebfcc370afd53d0
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10fda986580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bf27a408696a/disk-228da13e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/264d4943ab43/vmlinux-228da13e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a499b0d2a133/Image-228da13e.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/5a484378139b/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1481a3b6580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+87233e...@syzkaller.appspotmail.com

EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
Unable to handle kernel paging request at virtual address dfff800000000007
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[dfff800000000007] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4555 Comm: syz.0.25 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __ext4_journal_get_write_access+0xc4/0x610 fs/ext4/ext4_jbd2.c:231
lr : __ext4_journal_get_write_access+0xa0/0x610 fs/ext4/ext4_jbd2.c:229
sp : ffff800021107560
x29: ffff8000211075e0 x28: dfff800000000000 x27: ffff0000d01ce000
x26: ffff700004220eb0 x25: 0000000000000038 x24: ffff0000d01ce068
x23: 0000000000000001 x22: ffff800021107580 x21: ffff0000cff4e000
x20: 0000000000000001 x19: ffff0000e06eb0e8 x18: ffff800011babf60
x17: 1fffe00033e9f77e x16: ffff8000082d8944 x15: ffff80001523d000
x14: 0000000000000001 x13: 1fffe0001a039c82 x12: 0000000000ff0100
x11: ff0080000a8e1dfc x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000007 x7 : ffff800008258510 x6 : 0000000000000000
x5 : 0000000000000001 x4 : ffff0000e06eb0e8 x3 : ffff0000cff4e000
x2 : 0000000000000000 x1 : ffff800011baebc0 x0 : 0000000000000000
Call trace:
__ext4_journal_get_write_access+0xc4/0x610 fs/ext4/ext4_jbd2.c:231
ext4_update_primary_sb fs/ext4/ioctl.c:67 [inline]
ext4_update_superblocks_fn+0x248/0xee8 fs/ext4/ioctl.c:221
ext4_update_overhead+0x128/0x15c fs/ext4/ioctl.c:1712
ext4_fill_super+0x23ec/0x61b0 fs/ext4/super.c:5712
get_tree_bdev+0x358/0x544 fs/super.c:1366
ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723
vfs_get_tree+0x90/0x274 fs/super.c:1573
do_new_mount+0x228/0x810 fs/namespace.c:3078
path_mount+0x5bc/0xe80 fs/namespace.c:3408
do_mount fs/namespace.c:3421 [inline]
__do_sys_mount fs/namespace.c:3629 [inline]
__se_sys_mount fs/namespace.c:3606 [inline]
__arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: 97ef46cb f9400328 9100e119 d343ff28 (387c6908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 97ef46cb bl 0xffffffffffbd1b2c
4: f9400328 ldr x8, [x25]
8: 9100e119 add x25, x8, #0x38
c: d343ff28 lsr x8, x25, #3
* 10: 387c6908 ldrb w8, [x8, x28] <-- trapping instruction


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