BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [] sock_hold include/net/sock.h:589 [inline] IP: [] l2tp_session_create+0x948/0x1030 net/l2tp/l2tp_core.c:1809 PGD b5514067 PUD b9206067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 29443 Comm: syz-executor3 Not tainted 4.4.150-g5541782 #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800934c4800 task.stack: ffff8801bef10000 RIP: 0010:[] [] sock_hold include/net/sock.h:589 [inline] RIP: 0010:[] [] l2tp_session_create+0x948/0x1030 net/l2tp/l2tp_core.c:1809 RSP: 0018:ffff8801bef17b48 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801d4826f00 RCX: ffffc90000c24000 RDX: 1ffff1003a904e10 RSI: ffffffff835a3493 RDI: ffff8801d4827080 RBP: ffff8801bef17bb8 R08: ffff8800934c5100 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8463a140 R12: ffff8801d4826d28 R13: ffff8801bef17cd0 R14: ffff8801d4826c80 R15: ffffffff835a2f70 FS: 00007fd37822d700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 000000008d9da000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff81140961 ffff8801d4826f20[ 435.261938] binder_alloc: binder_alloc_mmap_handler: 29368 20010000-20013000 already mapped failed -16 binder_alloc: 29368: binder_alloc_buf, no vma binder: 29368:29371 transaction failed 29189/-3, size 0-0 line 3137 binder: 29368:29371 ERROR: BC_REGISTER_LOOPER called without request ffff8801d4826dd8 ffff8801d4826c90 ffffffff838caa10 ffff8801d4826d30 ffff8801d4826dd0 ffff8801d4826fe0 d108c62200000000[ 435.308545] binder: 29368:29445 got reply transaction with no transaction stack binder: 29368:29445 transaction failed 29201/-71, size 80-8 line 2922 binder: undelivered TRANSACTION_COMPLETE binder: undelivered TRANSACTION_ERROR: 29189 binder: undelivered TRANSACTION_ERROR: 29201 binder: undelivered TRANSACTION_ERROR: 29189 binder: undelivered TRANSACTION_ERROR: 29201 ffff8801d3479100 0000000000000000[ 435.355780] binder: 29448:29453 ERROR: BC_REGISTER_LOOPER called without request binder_alloc: binder_alloc_mmap_handler: 29448 20010000-20013000 already mapped failed -16 binder: BINDER_SET_CONTEXT_MGR already set binder: 29448:29453 ioctl 40046207 0 returned -16 binder_alloc: 29448: binder_alloc_buf, no vma binder: 29448:29453 transaction failed 29189/-3, size 0-0 line 3137 binder: 29448:29456 ERROR: BC_REGISTER_LOOPER called without request binder: 29448:29453 got reply transaction with no transaction stack binder: 29448:29453 transaction failed 29201/-71, size 80-8 line 2922 binder: undelivered TRANSACTION_ERROR: 29201 binder: unexpected work type, 4, not freed binder: undelivered TRANSACTION_COMPLETE ffff8801d3479130 Call Trace: [] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725 [] SYSC_connect+0x1b8/0x300 net/socket.c:1558 [] SyS_connect+0x24/0x30 net/socket.c:1539 [] entry_SYSCALL_64_fastpath+0x22/0x9e Code: 00 00 48 8d bb 80 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 36 06 00 00 48 8b 83 80 01 00 00 ff 80 80 00 00 00 48 8d 43 20 48 89 c7 48 89 45 b0 e8 f1 13 RIP [] sock_hold include/net/sock.h:589 [inline] RIP [] l2tp_session_create+0x948/0x1030 net/l2tp/l2tp_core.c:1809 RSP CR2: 0000000000000080 binder: 29471:29474 ERROR: BC_REGISTER_LOOPER called without request binder_alloc: binder_alloc_mmap_handler: 29471 20010000-20013000 already mapped failed -16 binder: BINDER_SET_CONTEXT_MGR already set binder: 29471:29474 ioctl 40046207 0 returned -16 binder_alloc: 29471: binder_alloc_buf, no vma binder: 29471:29487 ERROR: BC_REGISTER_LOOPER called without request binder: 29471:29481 transaction failed 29189/-3, size 0-0 line 3137 ---[ end trace 52112cb539fe96ad ]---