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

syzbot
2026-05-07T03:52:29Z

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

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#syz test: git://repo/address.git branch-or-commit-hash
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