bisecting fixing commit since 14260788bbb9c94b0e36abc17294266b69dd46e4
building syzkaller on 3a75be00f50996031dd301d44b009d56db3485f0
testing commit 14260788bbb9c94b0e36abc17294266b69dd46e4 with gcc (GCC) 8.1.0
kernel signature: bff048b69a7ac4097f1c37ca617fd98f19bd5fa99d48984807c403bb6c7f262f
all runs: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
testing current HEAD a39e75458e1ceb7fefaa3a0bd9df21558713cf0d
testing commit a39e75458e1ceb7fefaa3a0bd9df21558713cf0d with gcc (GCC) 8.1.0
kernel signature: 6587dc7ef64c89092124ea574bacaf04cb978913390e15ac9d54293f80ee46df
run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted
run #1: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted
run #3: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted
run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted
run #6: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #7: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #8: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #9: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
revisions tested: 2, total time: 25m51.751818815s (build: 16m43.757252971s, test: 8m25.264401997s)
the crash still happens on HEAD
commit msg: Linux 4.19.130
crash: KASAN: null-ptr-deref Read in llcp_sock_getname
IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
==================================================================
BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:373 [inline]
BUG: KASAN: null-ptr-deref in llcp_sock_getname+0x341/0x440 net/nfc/llcp_sock.c:531
Read of size 1 at addr 0000000000000000 by task syz-executor.3/7429

CPU: 1 PID: 7429 Comm: syz-executor.3 Not tainted 4.19.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x123/0x177 lib/dump_stack.c:118
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report.cold.9+0x6d/0x309 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memcpy+0x23/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:373 [inline]
 llcp_sock_getname+0x341/0x440 net/nfc/llcp_sock.c:531
 __sys_getpeername+0x123/0x220 net/socket.c:1735
 __do_sys_getpeername net/socket.c:1748 [inline]
 __se_sys_getpeername net/socket.c:1745 [inline]
 __x64_sys_getpeername+0x6e/0xb0 net/socket.c:1745
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a679
Code: ad b6 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc88de99c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000034
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc88de9a6d4
R13: 00000000004c1400 R14: 00000000004d49d0 R15: 00000000ffffffff
==================================================================
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready