general protection fault in rhashtable_walk_start_check

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    f611a5b4a51f ibmvnic: Include missing return code checks i..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=15ecaa46400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=531a917630d2a492
dashboard link: https://syzkaller.appspot.com/bug?extid=e93a2c41f91b8e2c7d9b
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15cb3cb2400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12d56e3e400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e93a2c41f91b8e2c7d9b@xxxxxxxxxxxxxxxxxxxxxxxxx

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 4663 Comm: syz-executor272 Not tainted 4.19.0-rc1+ #78
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:rhashtable_walk_start_check+0xd3/0x1400 lib/rhashtable.c:717
Code: f2 c7 40 30 f2 f2 f2 f2 c7 40 34 00 f2 f2 f2 65 48 8b 04 25 28 00 00  
00 48 89 45 d0 31 c0 e8 94 9e 0b fe 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 0f  
85 a4 0f 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff8801ba726ee8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff852abf68
RDX: 0000000000000000 RSI: ffffffff837121ec RDI: 0000000000000000
RBP: ffff8801ba727130 R08: ffff8801ba750780 R09: ffffed00374fcf3c
R10: ffffed00374fcf3c R11: ffff8801ba7e79e3 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8801ba727270 R15: fffffffffffff000
FS:  0000000001b0b880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000100 CR3: 00000001bbf40000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rhashtable_walk_start include/linux/rhashtable.h:244 [inline]
 tipc_nl_sk_walk+0x52/0x1d0 net/tipc/socket.c:3236
 tipc_nl_sk_dump+0x24/0x30 net/tipc/socket.c:3366
 __tipc_nl_compat_dumpit.isra.11+0x20b/0xad0 net/tipc/netlink_compat.c:192
 tipc_nl_compat_dumpit+0x1f4/0x440 net/tipc/netlink_compat.c:265
 tipc_nl_compat_handle net/tipc/netlink_compat.c:1142 [inline]
 tipc_nl_compat_recv+0x12b3/0x19a0 net/tipc/netlink_compat.c:1205
 genl_family_rcv_msg+0x8a3/0x1140 net/netlink/genetlink.c:601
 genl_rcv_msg+0xc6/0x168 net/netlink/genetlink.c:626
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2454
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:637
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x5a0/0x760 net/netlink/af_netlink.c:1343
 netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1908
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:631
 ___sys_sendmsg+0x7fd/0x930 net/socket.c:2114
 __sys_sendmsg+0x11d/0x290 net/socket.c:2152
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg net/socket.c:2159 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2159
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4400e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe84ec3538 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400e9
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401970
R13: 0000000000401a00 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace c8a9aaea5d0de646 ]---
RIP: 0010:rhashtable_walk_start_check+0xd3/0x1400 lib/rhashtable.c:717
Code: f2 c7 40 30 f2 f2 f2 f2 c7 40 34 00 f2 f2 f2 65 48 8b 04 25 28 00 00  
00 48 89 45 d0 31 c0 e8 94 9e 0b fe 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 0f  
85 a4 0f 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff8801ba726ee8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff852abf68
RDX: 0000000000000000 RSI: ffffffff837121ec RDI: 0000000000000000
RBP: ffff8801ba727130 R08: ffff8801ba750780 R09: ffffed00374fcf3c
R10: ffffed00374fcf3c R11: ffff8801ba7e79e3 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8801ba727270 R15: fffffffffffff000
FS:  0000000001b0b880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000100 CR3: 00000001bbf40000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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