bisecting fixing commit since b98aebd298246df37b472c52a2ee1023256d02e3
building syzkaller on 25bb509e5964da8203766c4039e4fef25e4689b1
testing commit b98aebd298246df37b472c52a2ee1023256d02e3 with gcc (GCC) 8.1.0
kernel signature: 7014c2f8d4d0b7c219a1d15d6484a7c5e9d104834c4632fb0216c1604e7df7a8
run #0: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #1: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #2: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #3: crashed: BUG: unable to handle kernel
run #4: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #5: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
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: BUG: unable to handle kernel
testing current HEAD ab9dfda232481dcfaf549ce774004d116fc80c13
testing commit ab9dfda232481dcfaf549ce774004d116fc80c13 with gcc (GCC) 8.1.0
kernel signature: 22a06c884966e8d51b7a2249d518fa3a3d5a10d1dfb6484fa902f346f19ffb0b
run #0: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
run #1: crashed: BUG: unable to handle kernel
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted
run #3: crashed: BUG: unable to handle kernel
run #4: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
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: 25m37.724827753s (build: 18m10.127448218s, test: 5m58.191600051s)
the crash still happens on HEAD
commit msg: Linux 4.14.180
crash: KASAN: null-ptr-deref Read in llcp_sock_getname
IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready
==================================================================
BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:347 [inline]
BUG: KASAN: null-ptr-deref in llcp_sock_getname+0x378/0x480 net/nfc/llcp_sock.c:532
Read of size 3 at addr           (null) by task syz-executor.2/7190

CPU: 1 PID: 7190 Comm: syz-executor.2 Not tainted 4.14.180-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xf7/0x13b lib/dump_stack.c:58
 kasan_report_error mm/kasan/report.c:349 [inline]
 kasan_report.cold.8+0x6d/0x2d3 mm/kasan/report.c:409
 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:347 [inline]
 llcp_sock_getname+0x378/0x480 net/nfc/llcp_sock.c:532
 SYSC_getpeername+0x122/0x250 net/socket.c:1715
 SyS_getpeername+0x9/0x10 net/socket.c:1699
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459f39
RSP: 002b:00007f2c676dac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000034
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f39
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2c676db6d4
R13: 00000000004c0bd0 R14: 00000000004d3668 R15: 00000000ffffffff
==================================================================
IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready
bridge0: port 2(bridge_slave_1) entered blocking state
bridge0: port 2(bridge_slave_1) entered forwarding state