[syzbot] [squashfs?] general protection fault in squashfs_copy_data

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cee73b1e840c Merge tag 'riscv-for-linus-7.0-mw1' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17ff615a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6d9e410399043c26
dashboard link: https://syzkaller.appspot.com/bug?extid=a9747fe1c35a5b115d3f
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=131e86e6580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=171e86e6580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a804e6ee01e8/disk-cee73b1e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6bf476ceaefd/vmlinux-cee73b1e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bc7592aa375b/bzImage-cee73b1e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/8dd42118c823/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a9747f...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 8
Oops: general protection fault, probably for non-canonical address 0xe00fed1004f4f8aa: 0000 [#1] SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x007f888027a7c550-0x007f888027a7c557]
CPU: 1 UID: 0 PID: 5972 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:squashfs_copy_data+0xde/0x220 fs/squashfs/cache.c:308
Code: 74 08 4c 89 e7 e8 52 c8 91 ff 4c 63 fd 49 c1 ef 09 49 83 e7 f8 4d 03 3c 24 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 24 c8 91 ff 89 e8 25 ff 0f 00 00 4d
RSP: 0018:ffffc90002ee7430 EFLAGS: 00010216
RAX: 000ff11004f4f8aa RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88807ca88000 RSI: 0000000000000077 RDI: 00000000ffffe0fe
RBP: 00000000ffffe0fe R08: ffff888022a8df2b R09: 1ffff11004551be5
R10: dffffc0000000000 R11: ffffed1004551be6 R12: ffff88802a9f61a0
R13: 0000000000000077 R14: 000000000000000c R15: 007f888027a7c550
FS: 000055555fb6d500(0000) GS:ffff8881255a0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000057f000 CR3: 0000000030d9f000 CR4: 0000000000350ef0
Call Trace:
<TASK>
squashfs_read_metadata+0x193/0x6d0 fs/squashfs/cache.c:357
squashfs_lookup+0x852/0xf20 fs/squashfs/namei.c:156
__lookup_slow+0x2b7/0x410 fs/namei.c:1916
lookup_slow+0x53/0x70 fs/namei.c:1933
walk_component fs/namei.c:2279 [inline]
link_path_walk+0xd1e/0x18d0 fs/namei.c:2647
path_lookupat+0xe4/0x8c0 fs/namei.c:2803
filename_lookup+0x256/0x5d0 fs/namei.c:2833
kern_path+0x3d/0x150 fs/namei.c:3040
unix_find_bsd net/unix/af_unix.c:1215 [inline]
unix_find_other+0x197/0xac0 net/unix/af_unix.c:1277
unix_dgram_connect+0x2cf/0xc20 net/unix/af_unix.c:1533
__sys_connect_file net/socket.c:2089 [inline]
__sys_connect+0x312/0x450 net/socket.c:2108
__do_sys_connect net/socket.c:2114 [inline]
__se_sys_connect net/socket.c:2111 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2111
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2536d9bf79
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:00007fffb506dda8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f2537015fa0 RCX: 00007f2536d9bf79
RDX: 000000000000006e RSI: 000020000057eff8 RDI: 0000000000000004
RBP: 00007f2536e327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2537015fac R14: 00007f2537015fa0 R15: 00007f2537015fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:squashfs_copy_data+0xde/0x220 fs/squashfs/cache.c:308
Code: 74 08 4c 89 e7 e8 52 c8 91 ff 4c 63 fd 49 c1 ef 09 49 83 e7 f8 4d 03 3c 24 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 24 c8 91 ff 89 e8 25 ff 0f 00 00 4d
RSP: 0018:ffffc90002ee7430 EFLAGS: 00010216
RAX: 000ff11004f4f8aa RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88807ca88000 RSI: 0000000000000077 RDI: 00000000ffffe0fe
RBP: 00000000ffffe0fe R08: ffff888022a8df2b R09: 1ffff11004551be5
R10: dffffc0000000000 R11: ffffed1004551be6 R12: ffff88802a9f61a0
R13: 0000000000000077 R14: 000000000000000c R15: 007f888027a7c550
FS: 000055555fb6d500(0000) GS:ffff8881254a0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f413658dd30 CR3: 0000000030d9f000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
0: 74 08 je 0xa
2: 4c 89 e7 mov %r12,%rdi
5: e8 52 c8 91 ff call 0xff91c85c
a: 4c 63 fd movslq %ebp,%r15
d: 49 c1 ef 09 shr $0x9,%r15
11: 49 83 e7 f8 and $0xfffffffffffffff8,%r15
15: 4d 03 3c 24 add (%r12),%r15
19: 4c 89 f8 mov %r15,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 ff mov %r15,%rdi
33: e8 24 c8 91 ff call 0xff91c85c
38: 89 e8 mov %ebp,%eax
3a: 25 ff 0f 00 00 and $0xfff,%eax
3f: 4d rex.WRB


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