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BUG: KASAN: use-after-free in sock_net include/net/sock.h:2328 [inline]
BUG: KASAN: use-after-free in sock_ioctl+0x438/0x470 net/socket.c:1006
Read of size 8 at addr ffff88807db573f0 by task syz-executor.2/23334

CPU: 1 PID: 23334 Comm: syz-executor.2 Not tainted 4.14.131 #25
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+0x138/0x19c lib/dump_stack.c:53
 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 sock_net include/net/sock.h:2328 [inline]
 sock_ioctl+0x438/0x470 net/socket.c:1006
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459519
RSP: 002b:00007f3b3446cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459519
RDX: 0000000020000040 RSI: 0000000000008917 RDI: 0000000000000005
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b3446d6d4
R13: 00000000004cdd40 R14: 00000000004d93e0 R15: 00000000ffffffff

Allocated by task 23332:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15d/0x7a0 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 sk_prot_alloc+0x171/0x2a0 net/core/sock.c:1470
 sk_alloc+0x39/0xd70 net/core/sock.c:1524
 pppol2tp_create+0x32/0x1f0 net/l2tp/l2tp_ppp.c:534
 pppox_create+0xf7/0x210 drivers/net/ppp/pppox.c:121
 __sock_create+0x2f6/0x620 net/socket.c:1275
 sock_create net/socket.c:1315 [inline]
 SYSC_socket net/socket.c:1345 [inline]
 SyS_socket+0xd3/0x170 net/socket.c:1325
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 23332:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcc/0x270 mm/slab.c:3815
 sk_prot_free net/core/sock.c:1507 [inline]
 __sk_destruct+0x493/0x5d0 net/core/sock.c:1586
 sk_destruct+0x67/0x80 net/core/sock.c:1594
 __sk_free+0x54/0x230 net/core/sock.c:1602
 sk_free+0x35/0x40 net/core/sock.c:1613
 sock_put include/net/sock.h:1653 [inline]
 pppol2tp_session_sock_put+0x66/0x80 net/l2tp/l2tp_ppp.c:271
 l2tp_tunnel_closeall+0x27f/0x380 net/l2tp/l2tp_core.c:1343
 l2tp_udp_encap_destroy+0x99/0x100 net/l2tp/l2tp_core.c:1366
 udpv6_destroy_sock+0xb3/0xd0 net/ipv6/udp.c:1444
 sk_common_release+0x6b/0x310 net/core/sock.c:2987
 udp_lib_close+0x16/0x20 include/net/udp.h:203
 inet_release+0xec/0x1c0 net/ipv4/af_inet.c:425
 inet6_release+0x53/0x80 net/ipv6/af_inet6.c:450
 __sock_release+0xce/0x2b0 net/socket.c:602
 sock_close+0x1b/0x30 net/socket.c:1139
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff88807db573c0
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 48 bytes inside of
 2048-byte region [ffff88807db573c0, ffff88807db57bc0)
The buggy address belongs to the page:
page:ffffea0001f6d580 count:1 mapcount:0 mapping:ffff88807db562c0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000008100(slab|head)
raw: 01fffc0000008100 ffff88807db562c0 0000000000000000 0000000100000003
raw: ffffea0001424920 ffffea0001753720 ffff8880aa800c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88807db57280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807db57300: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88807db57380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                             ^
 ffff88807db57400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807db57480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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