general protection fault in smap_list_map_remove

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    2bdea157b999 Merge branch 'sctp-fully-support-for-dscp-and..
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12192e0c400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f62553dc846b0692
dashboard link: https://syzkaller.appspot.com/bug?extid=ef78105c1713053fa8bb
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=16b40858400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=112ab052400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ef78105c1713053fa8bb@xxxxxxxxxxxxxxxxxxxxxxxxx

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: 4456 Comm: syz-executor610 Not tainted 4.18.0-rc3+ #45
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:do_raw_spin_lock+0x27/0x200 kernel/locking/spinlock_debug.c:111
Code: 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 56 41 55 41 54  
53 48 89 fb 48 83 c7 04 48 89 fa 48 c1 ea 03 48 83 ec 08 <0f> b6 14 02 48  
89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 7b
RSP: 0018:ffff8801ac2df9c0 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: 0000000000000230 RCX: 0000000000000000
RDX: 0000000000000046 RSI: 0000000000000000 RDI: 0000000000000234
RBP: ffff8801ac2df9e8 R08: 0000000000000001 R09: 0000000000000000
R10: ffffed0035724fa6 R11: ffff8801ab927d33 R12: dffffc0000000000
R13: ffff8801abf962c0 R14: 0000000000000220 R15: 0000000000000000
FS:  00007fcd332e0700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff2b4fcd5c CR3: 00000001d1f19000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x39/0x40 kernel/locking/spinlock.c:168
 spin_lock_bh include/linux/spinlock.h:315 [inline]
 smap_list_map_remove+0x96/0x350 kernel/bpf/sockmap.c:1670
 sock_map_ctx_update_elem.isra.21+0x3ab/0x570 kernel/bpf/sockmap.c:1981
 sock_map_update_elem+0x1b9/0x3b0 kernel/bpf/sockmap.c:2072
 map_update_elem+0x5c4/0xc90 kernel/bpf/syscall.c:765
 __do_sys_bpf kernel/bpf/syscall.c:2296 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:2267 [inline]
 __x64_sys_bpf+0x32d/0x510 kernel/bpf/syscall.c:2267
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445d19
Code: e8 2c b7 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 2b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fcd332dfce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445d19
RDX: 0000000000000020 RSI: 0000000020000180 RDI: 0000000000000002
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd667bb2bf R14: 00007fcd332e09c0 R15: 0000000000000005
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace fbe082eee969c5a2 ]---
RIP: 0010:do_raw_spin_lock+0x27/0x200 kernel/locking/spinlock_debug.c:111
Code: 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 56 41 55 41 54  
53 48 89 fb 48 83 c7 04 48 89 fa 48 c1 ea 03 48 83 ec 08 <0f> b6 14 02 48  
89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 7b
RSP: 0018:ffff8801ac2df9c0 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: 0000000000000230 RCX: 0000000000000000
RDX: 0000000000000046 RSI: 0000000000000000 RDI: 0000000000000234
RBP: ffff8801ac2df9e8 R08: 0000000000000001 R09: 0000000000000000
R10: ffffed0035724fa6 R11: ffff8801ab927d33 R12: dffffc0000000000
R13: ffff8801abf962c0 R14: 0000000000000220 R15: 0000000000000000
FS:  00007fcd332e0700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff2b4fcd5c CR3: 00000001d1f19000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches