[v6.6] general protection fault in metapage_writepage (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cbb31f77b879 Linux 6.6.121
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=173a2bfa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a950bf7c0bff9f9
dashboard link: https://syzkaller.appspot.com/bug?extid=7604ca7055db760ddf76
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6436cbae3604/disk-cbb31f77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f3a3d318f99/vmlinux-cbb31f77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84920a2a012f/bzImage-cbb31f77.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7604ca...@syzkaller.appspotmail.com

bn = 72c, index = 96
bn = 0, index = 0
bn = 72c, index = 96
bn = 0, index = 0
bn = 72c, index = 96
bn = 0, index = 0
bn = 0, index = 0
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 8472 Comm: syz.1.750 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:metapage_writepage+0xa3/0x11f0 fs/jfs/jfs_metapage.c:340
Code: f3 e8 d1 d2 81 fe 4c 8d 73 18 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 07 fa d9 fe 4d 8b 36 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 ee f9 d9 fe 4d 8b 2e 43 c6 44 3c
RSP: 0000:ffffc90003a77700 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffea0000b791c0 RCX: 0000000000080000
RDX: ffffc9000d67b000 RSI: 0000000000027e22 RDI: 0000000000027e23
RBP: ffffc90003a777f0 R08: ffffea0000b791f7 R09: 1ffffd400016f23e
R10: dffffc0000000000 R11: fffff9400016f23f R12: 1ffff9200074eee8
R13: ffffea0000b791f4 R14: 0000000000000000 R15: dffffc0000000000
FS: 00007f309bd016c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7431804000 CR3: 000000002c1ed000 CR4: 00000000003506e0
Call Trace:
<TASK>
metapage_write_one+0x2d3/0x790 fs/jfs/jfs_metapage.c:710
release_metapage+0x48a/0x870 fs/jfs/jfs_metapage.c:778
dtSearch+0x1c45/0x21b0 fs/jfs/jfs_dtree.c:793
jfs_symlink+0x854/0xfa0 fs/jfs/namei.c:1016
vfs_symlink+0x138/0x2b0 fs/namei.c:4481
do_symlinkat+0x1ba/0x400 fs/namei.c:4507
__do_sys_symlinkat fs/namei.c:4523 [inline]
__se_sys_symlinkat fs/namei.c:4520 [inline]
__x64_sys_symlinkat+0x99/0xb0 fs/namei.c:4520
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f309ad9acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f309bd01028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f309b015fa0 RCX: 00007f309ad9acb9
RDX: 00002000000007c0 RSI: 0000000000000005 RDI: 0000200000000440
RBP: 00007f309ae08bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f309b016038 R14: 00007f309b015fa0 R15: 00007ffd5786b6e8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:metapage_writepage+0xa3/0x11f0 fs/jfs/jfs_metapage.c:340
Code: f3 e8 d1 d2 81 fe 4c 8d 73 18 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 07 fa d9 fe 4d 8b 36 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 ee f9 d9 fe 4d 8b 2e 43 c6 44 3c
RSP: 0000:ffffc90003a77700 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffea0000b791c0 RCX: 0000000000080000
RDX: ffffc9000d67b000 RSI: 0000000000027e22 RDI: 0000000000027e23
RBP: ffffc90003a777f0 R08: ffffea0000b791f7 R09: 1ffffd400016f23e
R10: dffffc0000000000 R11: fffff9400016f23f R12: 1ffff9200074eee8
R13: ffffea0000b791f4 R14: 0000000000000000 R15: dffffc0000000000
FS: 00007f309bd016c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c34ee68 CR3: 000000002c1ed000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
0: f3 e8 d1 d2 81 fe repz call 0xfe81d2d7
6: 4c 8d 73 18 lea 0x18(%rbx),%r14
a: 4c 89 f0 mov %r14,%rax
d: 48 c1 e8 03 shr $0x3,%rax
11: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1)
16: 74 08 je 0x20
18: 4c 89 f7 mov %r14,%rdi
1b: e8 07 fa d9 fe call 0xfed9fa27
20: 4d 8b 36 mov (%r14),%r14
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 f7 mov %r14,%rdi
34: e8 ee f9 d9 fe call 0xfed9fa27
39: 4d 8b 2e mov (%r14),%r13
3c: 43 rex.XB
3d: c6 .byte 0xc6
3e: 44 rex.R
3f: 3c .byte 0x3c


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