general protection fault in reuseport_add_sock

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    f9bcc9f3ee4f net: ethernet: freescale: set FEC ethtool reg..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=158a10f3400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8f00801d7b7c4fe6
dashboard link: https://syzkaller.appspot.com/bug?extid=675ee297acac988852c1
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+675ee297acac988852c1@xxxxxxxxxxxxxxxxxxxxxxxxx

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
kobject: 'loop2' (000000005809b865): kobject_uevent_env
CPU: 1 PID: 14725 Comm: syz-executor.3 Not tainted 5.0.0-rc5+ #78
kobject: 'loop2' (000000005809b865): fill_kobj_path: path  
= '/devices/virtual/block/loop2'
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:reuseport_add_sock+0x187/0x8f0 net/core/sock_reuseport.c:170
Code: e8 ce 4e f2 fb 66 83 fb 01 0f 85 54 06 00 00 e8 5f 4d f2 fb 4d 8d 74  
24 12 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <0f> b6 14 02 4c  
89 f0 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 fc
RSP: 0018:ffff888066abfca0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc9000c432000
RDX: 0000000000000002 RSI: ffffffff857d8dc1 RDI: 0000000000000005
kobject: 'loop4' (00000000b88abefc): kobject_uevent_env
RBP: ffff888066abfd08 R08: ffff888064ff43c0 R09: fffffbfff1264fcd
R10: fffffbfff1264fcc R11: ffffffff89327e63 R12: 0000000000000000
R13: ffff888098d9c800 R14: 0000000000000012 R15: 0000000000000000
kobject: 'loop4' (00000000b88abefc): fill_kobj_path: path  
= '/devices/virtual/block/loop4'
FS:  00007f02a40cf700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004563fa CR3: 000000009ae04000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __sctp_hash_endpoint net/sctp/input.c:758 [inline]
 sctp_hash_endpoint+0x523/0x5d0 net/sctp/input.c:786
 sctp_listen_start net/sctp/socket.c:7967 [inline]
 sctp_inet_listen+0x5b2/0x880 net/sctp/socket.c:8022
kobject: 'loop5' (0000000099e34deb): kobject_uevent_env
 __sys_listen+0x19b/0x270 net/socket.c:1515
kobject: 'loop5' (0000000099e34deb): fill_kobj_path: path  
= '/devices/virtual/block/loop5'
 __do_sys_listen net/socket.c:1524 [inline]
 __se_sys_listen net/socket.c:1522 [inline]
 __x64_sys_listen+0x54/0x80 net/socket.c:1522
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e29
kobject: 'loop1' (00000000259faa1c): kobject_uevent_env
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f02a40cec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000032
kobject: 'loop1' (00000000259faa1c): fill_kobj_path: path  
= '/devices/virtual/block/loop1'
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457e29
RDX: 0000000000000000 RSI: 0000000100000001 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f02a40cf6d4
R13: 00000000004c3a2d R14: 00000000004d6940 R15: 00000000ffffffff
Modules linked in:
---[ end trace 3ce5847aad8cc1f0 ]---
RIP: 0010:reuseport_add_sock+0x187/0x8f0 net/core/sock_reuseport.c:170
Code: e8 ce 4e f2 fb 66 83 fb 01 0f 85 54 06 00 00 e8 5f 4d f2 fb 4d 8d 74  
24 12 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <0f> b6 14 02 4c  
89 f0 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 fc
RSP: 0018:ffff888066abfca0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc9000c432000
RDX: 0000000000000002 RSI: ffffffff857d8dc1 RDI: 0000000000000005
RBP: ffff888066abfd08 R08: ffff888064ff43c0 R09: fffffbfff1264fcd
R10: fffffbfff1264fcc R11: ffffffff89327e63 R12: 0000000000000000
R13: ffff888098d9c800 R14: 0000000000000012 R15: 0000000000000000
FS:  00007f02a40cf700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004563fa CR3: 000000009ae04000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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