linux-kernel - Re: [syzbot] [bpf?] [net?] BUG: unable to handle kernel NULL pointer dereference in sk_psock_verdict_data

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Message-ID: <000000000000c299950611406e55@google.com>
Date: Tue, 13 Feb 2024 01:58:14 -0800
From: syzbot <syzbot+fd7b34375c1c8ce29c93@...kaller.appspotmail.com>
To: andrii@...nel.org, ast@...nel.org, bpf@...r.kernel.org, 
	daniel@...earbox.net, davem@...emloft.net, edumazet@...gle.com, 
	jakub@...udflare.com, john.fastabend@...il.com, kuba@...nel.org, 
	linux-kernel@...r.kernel.org, mukattreyee@...il.com, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bpf?] [net?] BUG: unable to handle kernel NULL pointer
 dereference in sk_psock_verdict_data_ready

syzbot has found a reproducer for the following issue on:

HEAD commit:    577e4432f3ac tcp: add sanity checks to rx zerocopy
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=149a6fe0180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5e23375d0c3afdc8
dashboard link: https://syzkaller.appspot.com/bug?extid=fd7b34375c1c8ce29c93
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=17e2ddf4180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16c5d592180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d512cc35258d/disk-577e4432.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/83484fcd4968/vmlinux-577e4432.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dc2452784eec/bzImage-577e4432.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fd7b34375c1c8ce29c93@...kaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 8000000023d8f067 P4D 8000000023d8f067 PUD 7af79067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 5255 Comm: syz-executor278 Not tainted 6.8.0-rc1-syzkaller-00195-g577e4432f3ac #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:ffffc9000437f8c8 EFLAGS: 00010246
RAX: 1ffff1100482de5c RBX: ffff88802416f2e0 RCX: ffff888023a7bb80
RDX: 0000000000000000 RSI: ffff88802416f000 RDI: ffff888023a96800
RBP: ffffc9000437fad0 R08: ffffffff8957112c R09: 1ffffffff2590c84
R10: dffffc0000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000004 R14: ffffffff89570ff9 R15: ffff888023a96800
FS:  00007f8dfb0eb6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000023dae000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sk_psock_verdict_data_ready+0x232/0x340 net/core/skmsg.c:1230
 unix_stream_sendmsg+0x9b4/0x1230 net/unix/af_unix.c:2293
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f8dfb16c729
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:00007f8dfb0eb218 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8dfb1f6368 RCX: 00007f8dfb16c729
RDX: 0000000000040000 RSI: 0000000020000980 RDI: 0000000000000003
RBP: 00007f8dfb1f6360 R08: 00007fff2e940fc7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8dfb1f636c
R13: 00007f8dfb1c3074 R14: 656c6c616b7a7973 R15: 00007fff2e940fc8
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000437f8c8 EFLAGS: 00010246
RAX: 1ffff1100482de5c RBX: ffff88802416f2e0 RCX: ffff888023a7bb80
RDX: 0000000000000000 RSI: ffff88802416f000 RDI: ffff888023a96800
RBP: ffffc9000437fad0 R08: ffffffff8957112c R09: 1ffffffff2590c84
R10: dffffc0000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000004 R14: ffffffff89570ff9 R15: ffff888023a96800
FS:  00007f8dfb0eb6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000023dae000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.