netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
block nbd0: Device being setup by another task
==================================================================
BUG: KASAN: use-after-free in put_pid_ns+0x75/0x80 kernel/pid_namespace.c:202
Read of size 8 at addr ffff88809f8a74d0 by task syz-executor.3/20995

CPU: 0 PID: 20995 Comm: syz-executor.3 Not tainted 4.14.179-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+0x13e/0x194 lib/dump_stack.c:58
block nbd0: Device being setup by another task
 print_address_description.cold+0x7c/0x1e2 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+0xa9/0x2ae mm/kasan/report.c:393
 put_pid_ns+0x75/0x80 kernel/pid_namespace.c:202
 free_nsproxy+0xf7/0x1f0 kernel/nsproxy.c:182
 switch_task_namespaces+0x8f/0xb0 kernel/nsproxy.c:229
 copy_process.part.0+0x3c5c/0x6a50 kernel/fork.c:1971
 copy_process kernel/fork.c:1586 [inline]
 _do_fork+0x180/0xc80 kernel/fork.c:2070
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c829
RSP: 002b:00007f0c687e3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00000000004da960 RCX: 000000000045c829
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 000000002c000103
RBP: 000000000078c040 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 0000000000000076 R14: 00000000004c311e R15: 00007f0c687e46d4

Allocated by task 20995:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 kmem_cache_alloc+0x127/0x770 mm/slab.c:3552
 kmem_cache_zalloc include/linux/slab.h:651 [inline]
 create_pid_namespace kernel/pid_namespace.c:116 [inline]
 copy_pid_ns+0x1b2/0xa70 kernel/pid_namespace.c:186
 create_new_namespaces+0x25f/0x730 kernel/nsproxy.c:94
 copy_namespaces+0x27b/0x310 kernel/nsproxy.c:165
 copy_process.part.0+0x2603/0x6a50 kernel/fork.c:1774
 copy_process kernel/fork.c:1586 [inline]
 _do_fork+0x180/0xc80 kernel/fork.c:2070
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 3636:
 save_stack+0x32/0xa0 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]
 kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x792/0x1190 kernel/rcu/tree.c:2946
 __do_softirq+0x254/0x9bf kernel/softirq.c:288

The buggy address belongs to the object at ffff88809f8a6c98
 which belongs to the cache pid_namespace of size 2264
The buggy address is located 2104 bytes inside of
 2264-byte region [ffff88809f8a6c98, ffff88809f8a7570)
The buggy address belongs to the page:
page:ffffea00027e2980 count:1 mapcount:0 mapping:ffff88809f8a6340 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff88809f8a6340 0000000000000000 0000000100000003
raw: ffffea00028fa2a0 ffff8880a612cd48 ffff8880a612fe40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f8a7380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809f8a7400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809f8a7480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88809f8a7500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
 ffff88809f8a7580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fb fb
==================================================================