Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2026/5/6 6:48, syzbot 写道:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit:    74fe02ce122a Merge tag 'wq-for-7.1-rc2-fixes' of git://git..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16e895ce580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=59da38148f3a3d24
> dashboard link: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
> compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13a613ba580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-74fe02ce.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/c0a591d96864/vmlinux-74fe02ce.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/9f94fb623cd1/bzImage-74fe02ce.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
>
> Oops: general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] SMP KASAN NOPTI
> KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]

Thanks a lot. IIRC, this problem is in process. The link is 
https://patchwork.kernel.org/project/linux-rdma/patch/20260424013759.728288-1-kuniyu@google.com/

Hi, Kuniyuki Iwashima

I think you are fixing this problem. I hope that we can see your commit 
very soon.

Zhu Yanjun

> CPU: 3 UID: 0 PID: 5986 Comm: syz.3.20 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> RIP: 0010:kernel_sock_shutdown+0x47/0x70 net/socket.c:3785
> Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 33 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 20 49 8d 7c 24 68 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1a 49 8b 44 24 68 89 ee 48 89 df 5b 5d 41 5c ff e0
> RSP: 0018:ffffc9000391f180 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffff88802a2a0040 RCX: ffffffff8b8b72bd
> RDX: 000000000000000d RSI: ffffffff89553b32 RDI: 0000000000000068
> RBP: 0000000000000002 R08: 0000000000000001 R09: fffff52000723dfc
> R10: ffffc9000391efe7 R11: 0000000000000000 R12: 0000000000000000
> R13: ffff8880311b8000 R14: 0000000000000002 R15: 0000000000000018
> FS:  00007f602d1fe6c0(0000) GS:ffff8880d6675000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000561c522a6000 CR3: 000000002e99e000 CR4: 0000000000352ef0
> Call Trace:
>   <TASK>
>   udp_tunnel_sock_release+0x68/0x80 net/ipv4/udp_tunnel_core.c:202
>   rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
>   rxe_sock_put+0xae/0x130 drivers/infiniband/sw/rxe/rxe_net.c:639
>   rxe_net_del+0x83/0x120 drivers/infiniband/sw/rxe/rxe_net.c:660
>   rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
>   nldev_dellink+0x289/0x3c0 drivers/infiniband/core/nldev.c:1849
>   rdma_nl_rcv_msg+0x392/0x6f0 drivers/infiniband/core/netlink.c:195
>   rdma_nl_rcv_skb.constprop.0.isra.0+0x2cb/0x410 drivers/infiniband/core/netlink.c:239
>   netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
>   netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
>   netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
>   sock_sendmsg_nosec net/socket.c:787 [inline]
>   __sock_sendmsg net/socket.c:802 [inline]
>   ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
>   ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
>   __sys_sendmsg+0x170/0x220 net/socket.c:2784
>   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>   do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
>   entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f602db9cdd9
> 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:00007f602d1fe028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f602de16090 RCX: 00007f602db9cdd9
> RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000007
> RBP: 00007f602dc32d69 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f602de16128 R14: 00007f602de16090 R15: 00007ffc1d89c428
>   </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:kernel_sock_shutdown+0x47/0x70 net/socket.c:3785
> Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 33 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 20 49 8d 7c 24 68 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1a 49 8b 44 24 68 89 ee 48 89 df 5b 5d 41 5c ff e0
> RSP: 0018:ffffc9000391f180 EFLAGS: 00010202
>
> RAX: dffffc0000000000 RBX: ffff88802a2a0040 RCX: ffffffff8b8b72bd
> RDX: 000000000000000d RSI: ffffffff89553b32 RDI: 0000000000000068
> RBP: 0000000000000002 R08: 0000000000000001 R09: fffff52000723dfc
> R10: ffffc9000391efe7 R11: 0000000000000000 R12: 0000000000000000
> R13: ffff8880311b8000 R14: 0000000000000002 R15: 0000000000000018
> FS:  00007f602d1fe6c0(0000) GS:ffff8880d6675000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000561c522a6000 CR3: 000000002e99e000 CR4: 0000000000352ef0
> ----------------
> Code disassembly (best guess):
>     0:	fc                   	cld
>     1:	ff                   	lcall  (bad)
>     2:	df 48 89             	fisttps -0x77(%rax)
>     5:	fa                   	cli
>     6:	48 c1 ea 03          	shr    $0x3,%rdx
>     a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
>     e:	75 33                	jne    0x43
>    10:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
>    17:	fc ff df
>    1a:	4c 8b 63 20          	mov    0x20(%rbx),%r12
>    1e:	49 8d 7c 24 68       	lea    0x68(%r12),%rdi
>    23:	48 89 fa             	mov    %rdi,%rdx
>    26:	48 c1 ea 03          	shr    $0x3,%rdx
> * 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
>    2e:	75 1a                	jne    0x4a
>    30:	49 8b 44 24 68       	mov    0x68(%r12),%rax
>    35:	89 ee                	mov    %ebp,%esi
>    37:	48 89 df             	mov    %rbx,%rdi
>    3a:	5b                   	pop    %rbx
>    3b:	5d                   	pop    %rbp
>    3c:	41 5c                	pop    %r12
>    3e:	ff e0                	jmp    *%rax
>
>
> ---
> 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.

-- 
Best Regards,
Yanjun.Zhu