[Android 6.1] general protection fault in __ext4_journal_get_write_access

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b328aff1d7b8 UPSTREAM: cpufreq: scmi: Account for malforme..
git tree: android14-6.1
console output: https://syzkaller.appspot.com/x/log.txt?x=115d392f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4b268c91041514a
dashboard link: https://syzkaller.appspot.com/bug?extid=302e868f06095aee212d
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14fe2304580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=112681e2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2e8318e5ee7d/disk-b328aff1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/25a14742b7ac/vmlinux-b328aff1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bffb7e4ce555/bzImage-b328aff1.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0b5a20d385e4/mount_1.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11dab334580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+302e86...@syzkaller.appspotmail.com

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


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