bisecting fixing commit since ddef1e8e3f6eb26034833b7255e3fa584d54a230 building syzkaller on 5ea87a6638e52a94361b26b8576a1605585815fb testing commit ddef1e8e3f6eb26034833b7255e3fa584d54a230 with gcc (GCC) 8.1.0 kernel signature: c6ff19fc82d903bf34212e746e1f9857797d1c2df5c21ef407093e1e6495e4de run #0: crashed: KASAN: null-ptr-deref 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 in llcp_sock_getname 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: BUG: unable to handle kernel NULL pointer dereference in corrupted run #9: crashed: KASAN: null-ptr-deref Read in llcp_sock_getname testing current HEAD e0f8b8a65a473a8baa439cf865a694bbeb83fe90 testing commit e0f8b8a65a473a8baa439cf865a694bbeb83fe90 with gcc (GCC) 8.1.0 kernel signature: 569cddff9339451bd3c643e7e898e62c45996302ff3de4a473a0a8faf4a26c73 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 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: BUG: unable to handle kernel NULL pointer dereference in corrupted run #8: crashed: BUG: unable to handle kernel run #9: crashed: KASAN: null-ptr-deref in llcp_sock_getname revisions tested: 2, total time: 23m8.492091806s (build: 16m12.170965803s, test: 6m26.522394239s) the crash still happens on HEAD commit msg: Linux 4.14.170 crash: KASAN: null-ptr-deref in llcp_sock_getname IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes 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:347 [inline] BUG: KASAN: null-ptr-deref in llcp_sock_getname+0x378/0x480 net/nfc/llcp_sock.c:532 BUG: unable to handle kernel Read of size 43 at addr (null) by task syz-executor.1/7274 NULL pointer dereference at (null) IP: memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54 CPU: 1 PID: 7274 Comm: syz-executor.1 Not tainted 4.14.170-syzkaller #0 PGD 852a2067 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 P4D 852a2067 Call Trace: PUD a4881067 __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xf7/0x13b lib/dump_stack.c:58 PMD 0 kasan_report_error mm/kasan/report.c:349 [inline] kasan_report.cold.8+0x6d/0x2d3 mm/kasan/report.c:409 Oops: 0000 [#1] PREEMPT SMP KASAN check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 Modules linked in: 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 CPU: 0 PID: 7277 Comm: syz-executor.4 Not tainted 4.14.170-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809f99a080 task.stack: ffff8880a4f88000 RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54 RSP: 0018:ffff8880a4f8fcb8 EFLAGS: 00010246 RAX: ffff8880a4f8fe22 RBX: 000000000000002b RCX: 000000000000002b SyS_getpeername+0x9/0x10 net/socket.c:1699 RDX: 000000000000002b RSI: 0000000000000000 RDI: ffff8880a4f8fe22 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 RBP: ffff8880a4f8fcd8 R08: ffffed10149f1fca R09: ffffed10149f1fc4 entry_SYSCALL_64_after_hwframe+0x42/0xb7 R10: ffffed10149f1fc9 R11: ffff8880a4f8fe4c R12: ffff8880a4f8fe22 RIP: 0033:0x459f49 R13: 0000000000000000 R14: ffff88809b2915d0 R15: 0000000000000000 RSP: 002b:00007fc3b98d5c78 EFLAGS: 00000246 FS: 00007f3bb68bf700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000 ORIG_RAX: 0000000000000034 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 CR2: 0000000000000000 CR3: 000000009bc1e000 CR4: 00000000001406f0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc3b98d66d4 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 R13: 00000000004c0bf0 R14: 00000000004d37a8 R15: 00000000ffffffff ================================================================== Call Trace: 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: 0033:0x459f49 RSP: 002b:00007f3bb68bec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000034 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3bb68bf6d4 R13: 00000000004c0bf0 R14: 00000000004d37a8 R15: 00000000ffffffff Code: 90 90 90 90 90 eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 RIP: memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54 RSP: ffff8880a4f8fcb8 CR2: 0000000000000000 BUG: unable to handle kernel NULL pointer dereference at (null) ---[ end trace c263c5d89e97d87b ]--- IP: memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54 PGD a13da067 P4D a13da067 PUD a13db067 PMD 0 Oops: 0000 [#2] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 7281 Comm: syz-executor.5 Tainted: G B D 4.14.170-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809bc66100 task.stack: ffff888080680000 RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:54