[v6.1] BUG: unable to handle kernel NULL pointer dereference in sk_psock_verdict_data_ready

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f1bb70486c9c Linux 6.1.77
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12150b98180000
kernel config: https://syzkaller.appspot.com/x/.config?x=39447811cb133e7e
dashboard link: https://syzkaller.appspot.com/bug?extid=928fd41f9ea0b8e6140e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1644c684180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16081e78180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b4e70e158586/disk-f1bb7048.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6fd889f445ac/vmlinux-f1bb7048.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c8bf6d15492/bzImage-f1bb7048.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+928fd4...@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 72f73067 P4D 72f73067 PUD 23248067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4454 Comm: syz-executor990 Not tainted 6.1.77-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000402f928 EFLAGS: 00010246
RAX: 1ffff1100f652a5c RBX: ffff88807b2952e0 RCX: ffff888074ca3b80
RDX: 0000000000000000 RSI: ffff88807b295000 RDI: ffff88801f1ef000
RBP: ffffc9000402fb30 R08: ffffffff8896bb3e R09: fffffbfff2092245
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000004 R14: ffffffff8896ba1d R15: ffff88801f1ef000
FS: 00007f36f643b6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000183a4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
sk_psock_verdict_data_ready+0x210/0x330 net/core/skmsg.c:1221
unix_stream_sendmsg+0x8fd/0x1070 net/unix/af_unix.c:2241
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514
___sys_sendmsg net/socket.c:2568 [inline]
__sys_sendmsg+0x2a9/0x390 net/socket.c:2597
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f36f64bc729
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f36f643b218 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f36f6546368 RCX: 00007f36f64bc729
RDX: 0000000000040000 RSI: 0000000020000980 RDI: 0000000000000003
RBP: 00007f36f6546360 R08: 00007ffd47365c37 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f36f654636c
R13: 00007f36f6513074 R14: 656c6c616b7a7973 R15: 00007ffd47365c38
</TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000402f928 EFLAGS: 00010246
RAX: 1ffff1100f652a5c RBX: ffff88807b2952e0 RCX: ffff888074ca3b80
RDX: 0000000000000000 RSI: ffff88807b295000 RDI: ffff88801f1ef000
RBP: ffffc9000402fb30 R08: ffffffff8896bb3e R09: fffffbfff2092245
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000004 R14: ffffffff8896ba1d R15: ffff88801f1ef000
FS: 00007f36f643b6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000183a4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot suspects this issue was fixed by commit:

commit 4588b13abcbd561ec67f5b3c1cb2eff690990a54
Author: Shigeru Yoshida <syos...@redhat.com>
Date: Sun Feb 18 15:09:33 2024 +0000

bpf, sockmap: Fix NULL pointer dereference in sk_psock_verdict_data_ready()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=150aea6e180000
start commit: f1bb70486c9c Linux 6.1.77
git tree: linux-6.1.y

kernel config: https://syzkaller.appspot.com/x/.config?x=39447811cb133e7e
dashboard link: https://syzkaller.appspot.com/bug?extid=928fd41f9ea0b8e6140e

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1644c684180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16081e78180000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: bpf, sockmap: Fix NULL pointer dereference in sk_psock_verdict_data_ready()

For information about bisection process see: https://goo.gl/tpsmEJ#bisection