bisecting fixing commit since a844dc4c544291470aa69edbe2434b040794e269
building syzkaller on 1508f45368a309a3b1196a342b3d64ce7be4cc43
testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0
kernel signature: b44653b169017539a0ec704b9652d13db21438dd1c52e6b9203e303452f97b16
all runs: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname
testing current HEAD 3f2ecb86cb909da0b9157fd2952ad79924cbe5ae
testing commit 3f2ecb86cb909da0b9157fd2952ad79924cbe5ae with gcc (GCC) 8.1.0
kernel signature: b0da7dfdae31dd9158128bd5b609a5061eeac990a0357fdc41a14fc81416b9ba
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: KASAN: null-ptr-deref Read in llcp_sock_getname
run #4: crashed: KASAN: null-ptr-deref 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: KASAN: null-ptr-deref Read in llcp_sock_getname
revisions tested: 2, total time: 23m52.248277274s (build: 17m38.80151173s, test: 5m14.90257875s)
the crash still happens on HEAD
commit msg: Linux 4.14.212
crash: KASAN: null-ptr-deref Read in llcp_sock_getname
IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready
bond0: Enslaving bond_slave_1 as an active interface with an up link
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready
==================================================================
IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready
BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:372 [inline]
BUG: KASAN: null-ptr-deref in llcp_sock_getname+0x378/0x480 net/nfc/llcp_sock.c:532
Read of size 43 at addr           (null) by task syz-executor.3/6686

CPU: 0 PID: 6686 Comm: syz-executor.3 Not tainted 4.14.212-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:372 [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+0x46/0xbb
IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready
RIP: 0033:0x45a779
IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
RSP: 002b:00007f44be0cfc78 EFLAGS: 00000246
8021q: adding VLAN 0 to HW filter on device batadv0
 ORIG_RAX: 0000000000000034
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a779
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f44be0d06d4
R13: 00000000004c14b0 R14: 00000000004d56d8 R15: 00000000ffffffff
==================================================================