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* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
       [not found] <69ea344f.a00a0220.17a17.0040.GAE@google.com>
@ 2026-05-06 13:48 ` syzbot
  2026-05-06 14:28   ` Zhu Yanjun
  2026-05-07  1:30   ` Hillf Danton
  2026-05-07  3:52 ` syzbot
  1 sibling, 2 replies; 12+ messages in thread
From: syzbot @ 2026-05-06 13:48 UTC (permalink / raw)
  To: akpm, arjan, davem, dsahern, edumazet, horms, jgg, kuba, kuni1840,
	kuniyu, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzkaller-bugs, yanjun.zhu, zyjzyj2000

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]
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.

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
  2026-05-06 13:48 ` [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4) syzbot
@ 2026-05-06 14:28   ` Zhu Yanjun
  2026-05-06 15:19     ` Kuniyuki Iwashima
  2026-05-07  1:30   ` Hillf Danton
  1 sibling, 1 reply; 12+ messages in thread
From: Zhu Yanjun @ 2026-05-06 14:28 UTC (permalink / raw)
  To: syzbot, akpm, arjan, davem, dsahern, edumazet, horms, jgg, kuba,
	kuni1840, kuniyu, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzkaller-bugs, zyjzyj2000
  Cc: Kuniyuki Iwashima


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


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
  2026-05-06 14:28   ` Zhu Yanjun
@ 2026-05-06 15:19     ` Kuniyuki Iwashima
  0 siblings, 0 replies; 12+ messages in thread
From: Kuniyuki Iwashima @ 2026-05-06 15:19 UTC (permalink / raw)
  To: Zhu Yanjun
  Cc: syzbot, akpm, arjan, davem, dsahern, edumazet, horms, jgg, kuba,
	kuni1840, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzkaller-bugs, zyjzyj2000

On Wed, May 6, 2026 at 7:28 AM Zhu Yanjun <yanjun.zhu@linux.dev> wrote:
>
>
> 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.

Yes, I was sidetracked but will respin v3 this week.

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
  2026-05-06 13:48 ` [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4) syzbot
  2026-05-06 14:28   ` Zhu Yanjun
@ 2026-05-07  1:30   ` Hillf Danton
  2026-05-07  1:57     ` syzbot
  1 sibling, 1 reply; 12+ messages in thread
From: Hillf Danton @ 2026-05-07  1:30 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Wed, 06 May 2026 06:48:30 -0700	[thread overview]
> 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

#syz test

--- x/net/socket.c
+++ y/net/socket.c
@@ -3782,7 +3782,11 @@ EXPORT_SYMBOL(kernel_getpeername);
 
 int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how)
 {
-	return READ_ONCE(sock->ops)->shutdown(sock, how);
+	const struct proto_ops *ops = READ_ONCE(sock->ops);
+	if (ops)
+		return ops->shutdown(sock, how);
+	else
+		return 0;
 }
 EXPORT_SYMBOL(kernel_sock_shutdown);
 
--

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
  2026-05-07  1:30   ` Hillf Danton
@ 2026-05-07  1:57     ` syzbot
  0 siblings, 0 replies; 12+ messages in thread
From: syzbot @ 2026-05-07  1:57 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

lost connection to test machine



syzkaller login: qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x1cc000)
Warning: Permanently added '[localhost]:12337' (ED25519) to the list of known hosts.
[   97.096781][   T10] cfg80211: failed to load regulatory.db
[  152.152171][ T1025] ata1.00: exception Emask 0x0 SAct 0x800 SErr 0x0 action 0x6 frozen
[  152.155707][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.158413][ T1025] ata1.00: cmd 61/60:58:36:81:04/0e:00:00:00:00/40 tag 11 ncq dma 1884160 ou
[  152.158413][ T1025]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  152.167703][ T1025] ata1.00: status: { DRDY }
[  152.169908][ T1025] ata1: hard resetting link
[  152.494622][ T1025] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[  152.499274][ T1025] ata1.00: configured for UDMA/100
[  152.502602][ T1025] ata1: EH complete
qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0xc2000)
[  152.536671][ T1025] ata1.00: Read log 0x10 page 0x00 failed, Emask 0x1
[  152.539788][ T1025] ata1: failed to read log page 10h (errno=-5)
[  152.543143][ T1025] ata1.00: NCQ disabled due to excessive errors
[  152.546416][ T1025] ata1.00: exception Emask 0x1 SAct 0xfc00 SErr 0x0 action 0x0
[  152.549623][ T1025] ata1.00: irq_stat 0x41000000
[  152.552697][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.555276][ T1025] ata1.00: cmd 61/10:50:36:01:05/0c:00:00:00:00/40 tag 10 ncq dma 1581056 ou
[  152.555276][ T1025]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.564262][ T1025] ata1.00: status: { DRDY }
[  152.567499][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.570300][ T1025] ata1.00: cmd 61/b0:58:46:0d:05/03:00:00:00:00/40 tag 11 ncq dma 483328 out
[  152.570300][ T1025]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.578750][ T1025] ata1.00: status: { DRDY }
[  152.580940][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.584242][ T1025] ata1.00: cmd 61/c8:60:f6:10:05/05:00:00:00:00/40 tag 12 ncq dma 757760 out
[  152.584242][ T1025]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.591624][ T1025] ata1.00: status: { DRDY }
[  152.594145][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.597218][ T1025] ata1.00: cmd 61/f0:68:be:16:05/02:00:00:00:00/40 tag 13 ncq dma 385024 out
[  152.597218][ T1025]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.605201][ T1025] ata1.00: status: { DRDY }
[  152.607461][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.610119][ T1025] ata1.00: cmd 61/10:70:ae:19:05/06:00:00:00:00/40 tag 14 ncq dma 794624 out
[  152.610119][ T1025]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.617854][ T1025] ata1.00: status: { DRDY }
[  152.620399][ T1025] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.623555][ T1025] ata1.00: cmd 61/f8:78:be:1f:05/02:00:00:00:00/40 tag 15 ncq dma 389120 out
[  152.623555][ T1025]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.632127][ T1025] ata1.00: status: { DRDY }
[  152.635455][ T1025] ata1.00: configured for UDMA/100
[  152.638343][ T1025] ata1: EH complete
qemu-system-x86_64: hw/ide/core.c:934: ide_dma_cb: Assertion `prep_size >= 0 && prep_size <= n * 512' failed.
Connection to localhost closed by remote host.


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2539546880=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 23ad3581d162
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=23ad3581d162728720256cdd0a99f8702ec9c4c5 -X github.com/google/syzkaller/prog.gitRevisionDate=20260506-081407"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=23ad3581d162728720256cdd0a99f8702ec9c4c5 -X github.com/google/syzkaller/prog.gitRevisionDate=20260506-081407"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=23ad3581d162728720256cdd0a99f8702ec9c4c5 -X github.com/google/syzkaller/prog.gitRevisionDate=20260506-081407"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"23ad3581d162728720256cdd0a99f8702ec9c4c5\"
go: downloading golang.org/x/sync v0.20.0
go: downloading go.opentelemetry.io/otel/sdk v1.43.0
go: downloading google.golang.org/grpc v1.80.0
go: downloading go.opentelemetry.io/otel v1.43.0
go: downloading go.opentelemetry.io/otel/trace v1.43.0
go: downloading google.golang.org/genproto/googleapis/api v0.0.0-20260401024825-9d38bb4040a9
go: downloading golang.org/x/net v0.52.0
go: downloading google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9
go: downloading github.com/ianlancetaylor/demangle v0.0.0-20260505044615-1ff4bf46051f
go: downloading go.opentelemetry.io/otel/sdk/metric v1.43.0
go: downloading go.opentelemetry.io/otel/metric v1.43.0
go: downloading golang.org/x/crypto v0.49.0
go: downloading golang.org/x/text v0.35.0
go: downloading github.com/go-jose/go-jose/v4 v4.1.4
/usr/bin/ld: /tmp/ccMZeaB8.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         5862221f Merge tag 'parisc-for-7.1-rc3' of git://git.k..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=7f195f6be48c12ec
dashboard link: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1583eece580000


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
       [not found] <69ea344f.a00a0220.17a17.0040.GAE@google.com>
  2026-05-06 13:48 ` [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4) syzbot
@ 2026-05-07  3:52 ` syzbot
  2026-05-07 10:12   ` Edward Adam Davis
  2026-05-07 12:50   ` [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink() Edward Adam Davis
  1 sibling, 2 replies; 12+ messages in thread
From: syzbot @ 2026-05-07  3:52 UTC (permalink / raw)
  To: akpm, arjan, davem, dsahern, edumazet, hdanton, horms, jgg, kuba,
	kuni1840, kuniyu, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzkaller-bugs, yanjun.zhu, zyjzyj2000

syzbot has found a reproducer for the following issue on:

HEAD commit:    735d2f48cada Add linux-next specific files for 20260506
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14f0e56a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a88880f0f312e277
dashboard link: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
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=125c9f6c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166580ec580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e65b731bdb98/disk-735d2f48.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/60db2f3d3f2f/vmlinux-735d2f48.xz
kernel image: https://storage.googleapis.com/syzbot-assets/55da282f7ab4/bzImage-735d2f48.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com

rdma_rxe: rxe_newlink: failed to add lo
Oops: gen[  127.022080][ T5982] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 UID: 0 PID: 5982 Comm: syz.3.20 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:kernel_sock_shutdown+0x2a/0x70 net/socket.c:3803
Code: f3 0f 1e fa 41 57 41 56 41 54 53 89 f3 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 e1 25 c5 f8 4d 8d 7e 20 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 27 bf 2e f9 4d 8b 3f 49 83 c7 68
RSP: 0018:ffffc900015ef090 EFLAGS: 00010202
RAX: 0000000000000004 RBX: 0000000000000002 RCX: ffff88802dd89ec0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1007cc8979 R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000020
FS:  000055556d432500(0000) GS:ffff888125dca000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34563fff CR3: 0000000042b1c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 udp_tunnel_sock_release+0x6d/0x80 net/ipv4/udp_tunnel_core.c:197
 rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
 rxe_sock_put drivers/infiniband/sw/rxe/rxe_net.c:639 [inline]
 rxe_net_del+0xfb/0x290 drivers/infiniband/sw/rxe/rxe_net.c:660
 rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
 nldev_dellink+0x304/0x3d0 drivers/infiniband/core/nldev.c:1849
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0x6d7/0xa10 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x780/0x920 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1895
 sock_sendmsg_nosec+0x112/0x150 net/socket.c:797
 __sock_sendmsg net/socket.c:812 [inline]
 ____sys_sendmsg+0x55c/0x870 net/socket.c:2716
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2770
 __sys_sendmsg net/socket.c:2802 [inline]
 __do_sys_sendmsg net/socket.c:2807 [inline]
 __se_sys_sendmsg net/socket.c:2805 [inline]
 __x64_sys_sendmsg+0x1c3/0x2a0 net/socket.c:2805
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f89172fcdd9
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:00007ffe8bf8c018 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8917575fa0 RCX: 00007f89172fcdd9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000006
RBP: 00007f8917392d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8917575fac R14: 00007f8917575fa0 R15: 00007f8917575fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kernel_sock_shutdown+0x2a/0x70 net/socket.c:3803
Code: f3 0f 1e fa 41 57 41 56 41 54 53 89 f3 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 e1 25 c5 f8 4d 8d 7e 20 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 27 bf 2e f9 4d 8b 3f 49 83 c7 68
RSP: 0018:ffffc900015ef090 EFLAGS: 00010202
RAX: 0000000000000004 RBX: 0000000000000002 RCX: ffff88802dd89ec0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1007cc8979 R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000020
FS:  000055556d432500(0000) GS:ffff888125dca000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000042b1c000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	f3 0f 1e fa          	endbr64
   4:	41 57                	push   %r15
   6:	41 56                	push   %r14
   8:	41 54                	push   %r12
   a:	53                   	push   %rbx
   b:	89 f3                	mov    %esi,%ebx
   d:	49 89 fe             	mov    %rdi,%r14
  10:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  17:	fc ff df
  1a:	e8 e1 25 c5 f8       	call   0xf8c52600
  1f:	4d 8d 7e 20          	lea    0x20(%r14),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 27 bf 2e f9       	call   0xf92ebf60
  39:	4d 8b 3f             	mov    (%r15),%r15
  3c:	49 83 c7 68          	add    $0x68,%r15


---
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.

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
  2026-05-07  3:52 ` syzbot
@ 2026-05-07 10:12   ` Edward Adam Davis
  2026-05-07 12:02     ` syzbot
  2026-05-07 12:50   ` [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink() Edward Adam Davis
  1 sibling, 1 reply; 12+ messages in thread
From: Edward Adam Davis @ 2026-05-07 10:12 UTC (permalink / raw)
  To: syzbot+d8f76778263ab65c2b21; +Cc: linux-kernel, syzkaller-bugs

#syz test

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index 96c745d5bac4..3cb3cb7629fe 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -1816,6 +1816,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	return err;
 }
 
+static DEFINE_MUTEX(nldev_dellink_mutex);
+
 static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct netlink_ext_ack *extack)
 {
@@ -1846,7 +1848,9 @@ static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	 * implicitly scoped to the driver supporting dynamic link deletion like RXE.
 	 */
 	if (device->link_ops && device->link_ops->dellink) {
+		mutex_lock(&nldev_dellink_mutex);
 		err = device->link_ops->dellink(device);
+		mutex_unlock(&nldev_dellink_mutex);
 		if (err)
 			return err;
 	}


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* Re: [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4)
  2026-05-07 10:12   ` Edward Adam Davis
@ 2026-05-07 12:02     ` syzbot
  0 siblings, 0 replies; 12+ messages in thread
From: syzbot @ 2026-05-07 12:02 UTC (permalink / raw)
  To: eadavis, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
Tested-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com

Tested on:

commit:         735d2f48 Add linux-next specific files for 20260506
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15d2c196580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a88880f0f312e277
dashboard link: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=101a5f48580000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink()
  2026-05-07  3:52 ` syzbot
  2026-05-07 10:12   ` Edward Adam Davis
@ 2026-05-07 12:50   ` Edward Adam Davis
  2026-05-07 13:25     ` Zhu Yanjun
  1 sibling, 1 reply; 12+ messages in thread
From: Edward Adam Davis @ 2026-05-07 12:50 UTC (permalink / raw)
  To: syzbot+d8f76778263ab65c2b21
  Cc: akpm, arjan, davem, dsahern, edumazet, hdanton, horms, jgg, kuba,
	kuni1840, kuniyu, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzkaller-bugs, yanjun.zhu, zyjzyj2000

We must serialize calls to nldev_dellink() or risk a crash as syzbot
reported:

KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
Call Trace:
 udp_tunnel_sock_release+0x6d/0x80 net/ipv4/udp_tunnel_core.c:197
 rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
 rxe_sock_put drivers/infiniband/sw/rxe/rxe_net.c:639 [inline]
 rxe_net_del+0xfb/0x290 drivers/infiniband/sw/rxe/rxe_net.c:660
 rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
 
Fixes: a60e3f3d6fba ("RDMA/nldev: Add dellink function pointer")
Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
Tested-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 drivers/infiniband/core/nldev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index 96c745d5bac4..3cb3cb7629fe 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -1816,6 +1816,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	return err;
 }
 
+static DEFINE_MUTEX(nldev_dellink_mutex);
+
 static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct netlink_ext_ack *extack)
 {
@@ -1846,7 +1848,9 @@ static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	 * implicitly scoped to the driver supporting dynamic link deletion like RXE.
 	 */
 	if (device->link_ops && device->link_ops->dellink) {
+		mutex_lock(&nldev_dellink_mutex);
 		err = device->link_ops->dellink(device);
+		mutex_unlock(&nldev_dellink_mutex);
 		if (err)
 			return err;
 	}
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* Re: [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink()
  2026-05-07 12:50   ` [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink() Edward Adam Davis
@ 2026-05-07 13:25     ` Zhu Yanjun
  2026-05-07 13:40       ` Edward Adam Davis
  0 siblings, 1 reply; 12+ messages in thread
From: Zhu Yanjun @ 2026-05-07 13:25 UTC (permalink / raw)
  To: Edward Adam Davis, syzbot+d8f76778263ab65c2b21,
	yanjun.zhu@linux.dev
  Cc: akpm, arjan, davem, dsahern, edumazet, hdanton, horms, jgg, kuba,
	kuni1840, kuniyu, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzkaller-bugs, zyjzyj2000


在 2026/5/7 5:50, Edward Adam Davis 写道:
> We must serialize calls to nldev_dellink() or risk a crash as syzbot
> reported:
>
> KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
> Call Trace:
>   udp_tunnel_sock_release+0x6d/0x80 net/ipv4/udp_tunnel_core.c:197
>   rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
>   rxe_sock_put drivers/infiniband/sw/rxe/rxe_net.c:639 [inline]
>   rxe_net_del+0xfb/0x290 drivers/infiniband/sw/rxe/rxe_net.c:660
>   rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
>   
> Fixes: a60e3f3d6fba ("RDMA/nldev: Add dellink function pointer")
> Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
> Tested-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>

Thanks a lot. This looks like a good solution. Since the issue is 
reproducible,

have you sent this commit to syzbot for verification?

Thanks,

Zhu Yanjun

> ---
>   drivers/infiniband/core/nldev.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index 96c745d5bac4..3cb3cb7629fe 100644
> --- a/drivers/infiniband/core/nldev.c
> +++ b/drivers/infiniband/core/nldev.c
> @@ -1816,6 +1816,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
>   	return err;
>   }
>   
> +static DEFINE_MUTEX(nldev_dellink_mutex);
> +
>   static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
>   			  struct netlink_ext_ack *extack)
>   {
> @@ -1846,7 +1848,9 @@ static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
>   	 * implicitly scoped to the driver supporting dynamic link deletion like RXE.
>   	 */
>   	if (device->link_ops && device->link_ops->dellink) {
> +		mutex_lock(&nldev_dellink_mutex);
>   		err = device->link_ops->dellink(device);
> +		mutex_unlock(&nldev_dellink_mutex);
>   		if (err)
>   			return err;
>   	}

-- 
Best Regards,
Yanjun.Zhu


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink()
  2026-05-07 13:25     ` Zhu Yanjun
@ 2026-05-07 13:40       ` Edward Adam Davis
  2026-05-07 14:11         ` Zhu Yanjun
  0 siblings, 1 reply; 12+ messages in thread
From: Edward Adam Davis @ 2026-05-07 13:40 UTC (permalink / raw)
  To: yanjun.zhu
  Cc: akpm, arjan, davem, dsahern, eadavis, edumazet, hdanton, horms,
	jgg, kuba, kuni1840, kuniyu, leon, linux-kernel, linux-rdma,
	netdev, pabeni, syzbot+d8f76778263ab65c2b21, syzkaller-bugs,
	zyjzyj2000

On Thu, 7 May 2026 06:25:54 -0700, Zhu Yanjun wrote:
> > We must serialize calls to nldev_dellink() or risk a crash as syzbot
> > reported:
> >
> > KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
> > Call Trace:
> >   udp_tunnel_sock_release+0x6d/0x80 net/ipv4/udp_tunnel_core.c:197
> >   rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
> >   rxe_sock_put drivers/infiniband/sw/rxe/rxe_net.c:639 [inline]
> >   rxe_net_del+0xfb/0x290 drivers/infiniband/sw/rxe/rxe_net.c:660
> >   rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
> >
> > Fixes: a60e3f3d6fba ("RDMA/nldev: Add dellink function pointer")
> > Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
> > Closes: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
> > Tested-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
> > Signed-off-by: Edward Adam Davis <eadavis@qq.com>
> 
> Thanks a lot. This looks like a good solution. Since the issue is
> reproducible,
> 
> have you sent this commit to syzbot for verification?
The patch has been verified by syzbot.

BR,
Edward


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink()
  2026-05-07 13:40       ` Edward Adam Davis
@ 2026-05-07 14:11         ` Zhu Yanjun
  0 siblings, 0 replies; 12+ messages in thread
From: Zhu Yanjun @ 2026-05-07 14:11 UTC (permalink / raw)
  To: Edward Adam Davis, yanjun.zhu@linux.dev
  Cc: akpm, arjan, davem, dsahern, edumazet, hdanton, horms, jgg, kuba,
	kuni1840, kuniyu, leon, linux-kernel, linux-rdma, netdev, pabeni,
	syzbot+d8f76778263ab65c2b21, syzkaller-bugs, zyjzyj2000


在 2026/5/7 6:40, Edward Adam Davis 写道:
> On Thu, 7 May 2026 06:25:54 -0700, Zhu Yanjun wrote:
>>> We must serialize calls to nldev_dellink() or risk a crash as syzbot
>>> reported:
>>>
>>> KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
>>> Call Trace:
>>>    udp_tunnel_sock_release+0x6d/0x80 net/ipv4/udp_tunnel_core.c:197
>>>    rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
>>>    rxe_sock_put drivers/infiniband/sw/rxe/rxe_net.c:639 [inline]
>>>    rxe_net_del+0xfb/0x290 drivers/infiniband/sw/rxe/rxe_net.c:660
>>>    rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
>>>
>>> Fixes: a60e3f3d6fba ("RDMA/nldev: Add dellink function pointer")
>>> Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
>>> Closes: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
>>> Tested-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
>>> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
>> Thanks a lot. This looks like a good solution. Since the issue is
>> reproducible,
>>
>> have you sent this commit to syzbot for verification?
> The patch has been verified by syzbot.

Thanks a lot.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>

Zhu Yanjun

>
> BR,
> Edward
>
-- 
Best Regards,
Yanjun.Zhu


^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2026-05-07 14:12 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <69ea344f.a00a0220.17a17.0040.GAE@google.com>
2026-05-06 13:48 ` [syzbot] [rdma] general protection fault in kernel_sock_shutdown (4) syzbot
2026-05-06 14:28   ` Zhu Yanjun
2026-05-06 15:19     ` Kuniyuki Iwashima
2026-05-07  1:30   ` Hillf Danton
2026-05-07  1:57     ` syzbot
2026-05-07  3:52 ` syzbot
2026-05-07 10:12   ` Edward Adam Davis
2026-05-07 12:02     ` syzbot
2026-05-07 12:50   ` [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink() Edward Adam Davis
2026-05-07 13:25     ` Zhu Yanjun
2026-05-07 13:40       ` Edward Adam Davis
2026-05-07 14:11         ` Zhu Yanjun

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