bisecting fixing commit since a844dc4c544291470aa69edbe2434b040794e269 building syzkaller on 1508f45368a309a3b1196a342b3d64ce7be4cc43 testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0 kernel signature: e3f0704b224bafcad394fd815d5f94d03d3cb501d262252960251aa2ec395174 all runs: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname testing current HEAD cbfa1702aaf69b2311ea1b35e04f113c48368c67 testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.1.0 kernel signature: b8cca5b2ceda42d981fa66284ebbbda2398542d8c174152de2c0cd66909a4bef all runs: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname revisions tested: 2, total time: 21m57.239391809s (build: 15m31.857232501s, test: 5m57.802656183s) the crash still happens on HEAD commit msg: Linux 4.14.198 crash: KASAN: null-ptr-deref Read in llcp_sock_getname IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not 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.2/7311 8021q: adding VLAN 0 to HW filter on device bond0 CPU: 1 PID: 7311 Comm: syz-executor.2 Not tainted 4.14.198-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 RIP: 0033:0x45a779 RSP: 002b:00007f01088aec78 EFLAGS: 00000246 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: 00007f01088af6d4 R13: 00000000004c14b0 R14: 00000000004d56d8 R15: 00000000ffffffff ==================================================================