loop0: detected capacity change from 0 to 64
hfs: unable to locate alternate MDB
hfs: continuing without an alternate MDB
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 5338 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:handshake_complete+0x36/0x350 net/handshake/request.c:290
Code: 54 53 48 83 ec 10 48 89 54 24 08 89 f5 49 89 ff 49 bd 00 00 00 00 00 fc ff df e8 e5 00 72 f6 49 8d 5f 28 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 4b e7 d9 f6 48 8b 1b 4c 8d 63 30
RSP: 0018:ffffc9000a6e7320 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000028 RCX: 0000000000100000
RDX: ffffc90020f72000 RSI: 000000000000020a RDI: 000000000000020b
RBP: 00000000fffffffb R08: ffff8880380c7703 R09: 1ffff11007018ee0
R10: dffffc0000000000 R11: ffffed1007018ee1 R12: ffff8880362a5dd0
R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f363c7f56c0(0000) GS:ffff88808d22a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561618ba4ff8 CR3: 000000004114b000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 handshake_nl_accept_doit+0x3f1/0x830 net/handshake/netlink.c:129
 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x820 net/socket.c:2592
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f364038f7c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f363c7f5038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f36405e5fa0 RCX: 00007f364038f7c9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f3640413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f36405e6038 R14: 00007f36405e5fa0 R15: 00007ffc2babeaf8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:handshake_complete+0x36/0x350 net/handshake/request.c:290
Code: 54 53 48 83 ec 10 48 89 54 24 08 89 f5 49 89 ff 49 bd 00 00 00 00 00 fc ff df e8 e5 00 72 f6 49 8d 5f 28 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 4b e7 d9 f6 48 8b 1b 4c 8d 63 30
RSP: 0018:ffffc9000a6e7320 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000028 RCX: 0000000000100000
RDX: ffffc90020f72000 RSI: 000000000000020a RDI: 000000000000020b
RBP: 00000000fffffffb R08: ffff8880380c7703 R09: 1ffff11007018ee0
R10: dffffc0000000000 R11: ffffed1007018ee1 R12: ffff8880362a5dd0
R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f363c7f56c0(0000) GS:ffff88808d22a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f363c7d3fc8 CR3: 000000004114b000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	54                   	push   %rsp
   1:	53                   	push   %rbx
   2:	48 83 ec 10          	sub    $0x10,%rsp
   6:	48 89 54 24 08       	mov    %rdx,0x8(%rsp)
   b:	89 f5                	mov    %esi,%ebp
   d:	49 89 ff             	mov    %rdi,%r15
  10:	49 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%r13
  17:	fc ff df
  1a:	e8 e5 00 72 f6       	call   0xf6720104
  1f:	49 8d 5f 28          	lea    0x28(%r15),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 4b e7 d9 f6       	call   0xf6d9e784
  39:	48 8b 1b             	mov    (%rbx),%rbx
  3c:	4c 8d 63 30          	lea    0x30(%rbx),%r12