PPPIOCDETACH file->f_count=2
encrypted_key: insufficient parameters specified
PPPIOCDETACH file->f_count=3
PPPIOCDETACH file->f_count=2
==================================================================
BUG: KASAN: use-after-free in inet_shutdown+0x2d4/0x350 net/ipv4/af_inet.c:819
Read of size 4 at addr ffff8801bc3900c0 by task syz-executor4/24572

CPU: 0 PID: 24572 Comm: syz-executor4 Not tainted 4.15.0+ #302
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+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 inet_shutdown+0x2d4/0x350 net/ipv4/af_inet.c:819
 pppol2tp_session_close+0x92/0xf0 net/l2tp/l2tp_ppp.c:430
 l2tp_tunnel_closeall+0x305/0x410 net/l2tp/l2tp_core.c:1285
 l2tp_udp_encap_destroy+0x95/0x100 net/l2tp/l2tp_core.c:1308
 udpv6_destroy_sock+0x161/0x190 net/ipv6/udp.c:1407
 sk_common_release+0x6b/0x2f0 net/core/sock.c:2996
 udp_lib_close+0x15/0x20 include/net/udp.h:203
 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:427
 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:435
 sock_release+0x8d/0x1e0 net/socket.c:595
 sock_close+0x16/0x20 net/socket.c:1149
 __fput+0x327/0x7e0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x199/0x270 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ed/0x940 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x26/0x9b
RIP: 0033:0x453299
RSP: 002b:00007ff0b6fe9c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000071bf58 RCX: 0000000000453299
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000013
RBP: 0000000000000052 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ef850
R13: 00000000ffffffff R14: 00007ff0b6fea6d4 R15: 000000000000000a

Allocated by task 24576:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3541
 sock_alloc_inode+0x70/0x300 net/socket.c:244
 alloc_inode+0x65/0x180 fs/inode.c:209
 new_inode_pseudo+0x69/0x190 fs/inode.c:890
 sock_alloc+0x41/0x270 net/socket.c:565
 __sock_create+0x148/0x850 net/socket.c:1249
 sock_create net/socket.c:1325 [inline]
 SYSC_socket net/socket.c:1355 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1335
 do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x26/0x9b

Freed by task 24576:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3485 [inline]
 kmem_cache_free+0x83/0x2a0 mm/slab.c:3743
 sock_destroy_inode+0x56/0x70 net/socket.c:274
 destroy_inode+0x15d/0x200 fs/inode.c:266
 evict+0x57e/0x920 fs/inode.c:570
 iput_final fs/inode.c:1515 [inline]
 iput+0x7b9/0xaf0 fs/inode.c:1542
 dentry_unlink_inode+0x4b0/0x5e0 fs/dcache.c:371
 __dentry_kill+0x3de/0x700 fs/dcache.c:575
 dentry_kill fs/dcache.c:616 [inline]
 dput.part.21+0x6fb/0x830 fs/dcache.c:826
 dput+0x1f/0x30 fs/dcache.c:790
 __fput+0x51c/0x7e0 fs/file_table.c:227
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x199/0x270 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ed/0x940 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x26/0x9b

The buggy address belongs to the object at ffff8801bc3900c0
 which belongs to the cache sock_inode_cache of size 992
The buggy address is located 0 bytes inside of
 992-byte region [ffff8801bc3900c0, ffff8801bc3904a0)
The buggy address belongs to the page:
page:ffffea0006f0e400 count:1 mapcount:0 mapping:ffff8801bc3900c0 index:0xffff8801bc390ffd
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801bc3900c0 ffff8801bc390ffd 0000000100000003
raw: ffffea0006771320 ffffea0006aa41e0 ffff8801d980d9c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801bc38ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801bc390000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801bc390080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                           ^
 ffff8801bc390100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801bc390180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================