BUG: unable to handle kernel

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b98aebd2 Linux 4.14.150
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=163b8e18e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c52c93b368dac5a7
dashboard link: https://syzkaller.appspot.com/bug?extid=52f60d8337425a264f7e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=176263c4e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=161aea74e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+52f60d...@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
kauditd_printk_skb: 10 callbacks suppressed
audit: type=1400 audit(1572043682.545:36): avc: denied { map } for
pid=6730 comm="syz-executor888" path="/root/syz-executor888363741"
dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
==================================================================
BUG: unable to handle kernel
BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:347 [inline]
BUG: KASAN: null-ptr-deref in llcp_sock_getname+0x38f/0x4a0
net/nfc/llcp_sock.c:532
NULL pointer dereference at (null)
Read of size 63 at addr (null) by task syz-executor888/6739
IP: memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54

PGD 9bc60067
CPU: 0 PID: 6739 Comm: syz-executor888 Not tainted 4.14.150 #0
P4D 9bc60067
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
PUD 9207a067
Call Trace:
PMD 0
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x197 lib/dump_stack.c:53
Oops: 0000 [#1] PREEMPT SMP KASAN
kasan_report_error mm/kasan/report.c:349 [inline]
kasan_report mm/kasan/report.c:409 [inline]
kasan_report.cold+0x127/0x2af mm/kasan/report.c:393
Modules linked in:
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
memcpy+0x24/0x50 mm/kasan/kasan.c:302
CPU: 1 PID: 6737 Comm: syz-executor888 Not tainted 4.14.150 #0
memcpy include/linux/string.h:347 [inline]
llcp_sock_getname+0x38f/0x4a0 net/nfc/llcp_sock.c:532
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
sock_getsockopt+0xc0d/0x1840 net/core/sock.c:1276
task: ffff88808d2ae340 task.stack: ffff8880a7100000
RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54
RSP: 0018:ffff8880a7107bf8 EFLAGS: 00010246
RAX: ffff8880a7107d82 RBX: ffff8880a7107d70 RCX: 000000000000003f
SYSC_getsockopt net/socket.c:1892 [inline]
SyS_getsockopt+0x1bd/0x1e0 net/socket.c:1878
RDX: 000000000000003f RSI: 0000000000000000 RDI: ffff8880a7107d82
RBP: ffff8880a7107c18 R08: 1ffff11014e20fb0 R09: ffffed1014e20fb9
R10: ffffed1014e20fb8 R11: ffff8880a7107dc0 R12: 000000000000003f
R13: ffff8880a7107d82 R14: 0000000000000000 R15: ffff8880946e19c0
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
FS: 0000000001df2880(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
entry_SYSCALL_64_after_hwframe+0x42/0xb7
CR2: 0000000000000000 CR3: 0000000091656000 CR4: 00000000001406e0
RIP: 0033:0x4412b9
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
RSP: 002b:00007fff17f81598 EFLAGS: 00000246
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
ORIG_RAX: 0000000000000037
Call Trace:
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004412b9
RDX: 000000000000001c RSI: 0000000000000001 RDI: 0000000000000003
memcpy include/linux/string.h:347 [inline]
llcp_sock_getname+0x38f/0x4a0 net/nfc/llcp_sock.c:532
RBP: 00000000006cb018 R08: 0000000020000140 R09: 00000000004002c8
sock_getsockopt+0xc0d/0x1840 net/core/sock.c:1276
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402030
R13: 00000000004020c0 R14: 0000000000000000 R15: 0000000000000000
==================================================================


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