[squashfs?] general protection fault in cache_first_page

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=100cfa1b480000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=400ddff795d51da0f580
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+400ddf...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 17923 Comm: syz-executor.0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
RIP: 0010:cache_first_page+0x5c/0x90 fs/squashfs/page_actor.c:27
Code: 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 30 48 b8 00 00 00 00 00 fc ff df 48 8b 1b 48 89 da 48 c1 ea 03 <80> 3c 02 00 75 0c 48 8b 03 5b c3 e8 84 7b a4 ff eb bc 48 89 df e8
RSP: 0018:ffff8880a9bbfa88 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000010 RCX: ffffc900061e3000
RDX: 0000000000000002 RSI: ffffffff81f3e8b9 RDI: ffff88804deea630
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000001
R13: 00000000000001f8 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f6f99e01700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ed15e418e0 CR3: 00000000a0dd1000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
squashfs_first_page fs/squashfs/page_actor.h:70 [inline]
squashfs_read_data+0xabb/0x13a0 fs/squashfs/block.c:181
squashfs_read_table+0x184/0x1f0 fs/squashfs/cache.c:445
squashfs_read_xattr_id_table+0x208/0x440 fs/squashfs/xattr_id.c:108
squashfs_fill_super+0xcc0/0x1cf0 fs/squashfs/super.c:234
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2492 [inline]
do_mount+0x115c/0x2f50 fs/namespace.c:2822
ksys_mount+0xcf/0x130 fs/namespace.c:3038
__do_sys_mount fs/namespace.c:3052 [inline]
__se_sys_mount fs/namespace.c:3049 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3049
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f6f9b89062a
Code: 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6f99e00f88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000000001cf RCX: 00007f6f9b89062a
RDX: 0000000020000200 RSI: 0000000020000240 RDI: 00007f6f99e00fe0
RBP: 00007f6f99e01020 R08: 00007f6f99e01020 R09: 000000000000000f
R10: 000000000000000f R11: 0000000000000202 R12: 0000000020000200
R13: 0000000020000240 R14: 00007f6f99e00fe0 R15: 0000000020000040
Modules linked in:
---[ end trace 5b47b83cb395305d ]---
RIP: 0010:cache_first_page+0x5c/0x90 fs/squashfs/page_actor.c:27
Code: 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 30 48 b8 00 00 00 00 00 fc ff df 48 8b 1b 48 89 da 48 c1 ea 03 <80> 3c 02 00 75 0c 48 8b 03 5b c3 e8 84 7b a4 ff eb bc 48 89 df e8
RSP: 0018:ffff8880a9bbfa88 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000010 RCX: ffffc900061e3000
RDX: 0000000000000002 RSI: ffffffff81f3e8b9 RDI: ffff88804deea630
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000001
R13: 00000000000001f8 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f6f99e01700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4d71d4cff8 CR3: 00000000a0dd1000 CR4: 00000000003406e0
device vlan5 entered promiscuous mode
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
9: fc ff df
c: 48 c1 ea 03 shr $0x3,%rdx
10: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
14: 75 30 jne 0x46
16: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1d: fc ff df
20: 48 8b 1b mov (%rbx),%rbx
23: 48 89 da mov %rbx,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 75 0c jne 0x3c
30: 48 8b 03 mov (%rbx),%rax
33: 5b pop %rbx
34: c3 retq
35: e8 84 7b a4 ff callq 0xffa47bbe
3a: eb bc jmp 0xfffffff8
3c: 48 89 df mov %rbx,%rdi
3f: e8 .byte 0xe8


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