[Android 5.15] general protection fault in sk_psock_verdict_data_ready

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 050dc55b0457 Revert "net/sched: act_connmark: handle errno..
git tree: android13-5.15-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=168ac852580000
kernel config: https://syzkaller.appspot.com/x/.config?x=deffac0a782f1cb0
dashboard link: https://syzkaller.appspot.com/bug?extid=eb5af0b13a821f4ffe41
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=1471f39a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=146ab522580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/824d99904cff/disk-050dc55b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/099356de8ffe/vmlinux-050dc55b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/43bdc6ff8eed/bzImage-050dc55b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eb5af0...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000018: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000c0-0x00000000000000c7]
CPU: 1 PID: 4300 Comm: syz.3.1292 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:sk_psock_verdict_data_ready+0x143/0x1d0 net/core/skmsg.c:1256
Code: 24 50 48 c7 44 24 48 01 00 00 00 43 80 3c 2e 00 74 08 4c 89 ff e8 cd 1b d1 fd 41 bc c0 00 00 00 4d 03 27 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 ae 1b d1 fd 48 8b 7c 24 18 48 8d
RSP: 0018:ffffc90000e477e0 EFLAGS: 00010206
RAX: 0000000000000018 RBX: 1ffff920001c8f00 RCX: ffff88810b1962c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90000e47840
RBP: ffffc90000e478b0 R08: ffffc90000e4783f R09: ffffc90000e47820
R10: dffffc0000000000 R11: fffff520001c8f08 R12: 00000000000000c0
R13: dffffc0000000000 R14: 1ffff11021a03404 R15: ffff88810d01a020
FS: 00007f70239816c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f339c038060 CR3: 000000011d0d1000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
unix_stream_sendmsg+0x7d1/0xc90 net/unix/af_unix.c:2117
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2436
___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg net/socket.c:2526 [inline]
__x64_sys_sendmsg+0x206/0x2f0 net/socket.c:2526
x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7023b1ccb9
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:00007f7023981028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f7023d97fa0 RCX: 00007f7023b1ccb9
RDX: 0200000000000000 RSI: 0000200000000500 RDI: 0000000000000005
RBP: 00007f7023b8abf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7023d98038 R14: 00007f7023d97fa0 R15: 00007ffd059bce78
</TASK>
Modules linked in:
---[ end trace 79ec861c9278866e ]---
RIP: 0010:sk_psock_verdict_data_ready+0x143/0x1d0 net/core/skmsg.c:1256
Code: 24 50 48 c7 44 24 48 01 00 00 00 43 80 3c 2e 00 74 08 4c 89 ff e8 cd 1b d1 fd 41 bc c0 00 00 00 4d 03 27 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 ae 1b d1 fd 48 8b 7c 24 18 48 8d
RSP: 0018:ffffc90000e477e0 EFLAGS: 00010206
RAX: 0000000000000018 RBX: 1ffff920001c8f00 RCX: ffff88810b1962c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90000e47840
RBP: ffffc90000e478b0 R08: ffffc90000e4783f R09: ffffc90000e47820
R10: dffffc0000000000 R11: fffff520001c8f08 R12: 00000000000000c0
R13: dffffc0000000000 R14: 1ffff11021a03404 R15: ffff88810d01a020
FS: 00007f70239816c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000022a000 CR3: 000000011d0d1000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 24 50 and $0x50,%al
2: 48 c7 44 24 48 01 00 movq $0x1,0x48(%rsp)
9: 00 00
b: 43 80 3c 2e 00 cmpb $0x0,(%r14,%r13,1)
10: 74 08 je 0x1a
12: 4c 89 ff mov %r15,%rdi
15: e8 cd 1b d1 fd call 0xfdd11be7
1a: 41 bc c0 00 00 00 mov $0xc0,%r12d
20: 4d 03 27 add (%r15),%r12
23: 4c 89 e0 mov %r12,%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: 4c 89 e7 mov %r12,%rdi
34: e8 ae 1b d1 fd call 0xfdd11be7
39: 48 8b 7c 24 18 mov 0x18(%rsp),%rdi
3e: 48 rex.W
3f: 8d .byte 0x8d


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