RBP: 000000000076bf20 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 0000000000000074 R14: 00000000004c2cc6 R15: 0000000000000010
2938*16kB (UME) 2155*32kB (UME) 1124*64kB (UME) 245*128kB (UME) 98*256kB (UME) 70*512kB (UM) 18*1024kB (UM) 3*2048kB (UM) 73*4096kB (UM) = 617156kB
==================================================================
BUG: KASAN: use-after-free in put_pid_ns+0x80/0x90 kernel/pid_namespace.c:202
Read of size 8 at addr ffff8880a06e5b68 by task syz-executor.3/3783

CPU: 0 PID: 3783 Comm: syz-executor.3 Not tainted 4.14.171-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+0x142/0x197 lib/dump_stack.c:58
 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
 put_pid_ns+0x80/0x90 kernel/pid_namespace.c:202
 free_nsproxy+0x104/0x200 kernel/nsproxy.c:182
 switch_task_namespaces+0x98/0xb0 kernel/nsproxy.c:229
 exit_task_namespaces+0x18/0x20 kernel/nsproxy.c:234
 do_exit+0xa15/0x2cd0 kernel/exit.c:857
 do_group_exit+0x111/0x330 kernel/exit.c:955
 get_signal+0x381/0x1cd0 kernel/signal.c:2418
 do_signal+0x86/0x19a0 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x15c/0x220 arch/x86/entry/common.c:160
 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
RIP: 0033:0x45c429
RSP: 002b:00007fd58d1becf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c429
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd03d3c83f R14: 00007fd58d1bf9c0 R15: 000000000076bf2c

Allocated by task 3783:
 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
 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x780 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+0x1af/0xa50 kernel/pid_namespace.c:186
 create_new_namespaces+0x267/0x720 kernel/nsproxy.c:94
 unshare_nsproxy_namespaces+0xab/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2391 [inline]
 SyS_unshare+0x2f3/0x7e0 kernel/fork.c:2341
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 7:
 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]
 kmem_cache_free+0x83/0x2b0 mm/slab.c:3758
 delayed_free_pidns+0x89/0xb0 kernel/pid_namespace.c:166
 __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+0x7b8/0x12b0 kernel/rcu/tree.c:2946
 __do_softirq+0x244/0x9a0 kernel/softirq.c:288

The buggy address belongs to the object at ffff8880a06e5330
 which belongs to the cache pid_namespace of size 2264
The buggy address is located 2104 bytes inside of
 2264-byte region [ffff8880a06e5330, ffff8880a06e5c08)
The buggy address belongs to the page:
page:ffffea000281b900 count:1 mapcount:0 mapping:ffff8880a06e4080 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a06e4080 0000000000000000 0000000100000003
raw: ffffea0001817aa0 ffffea000224ee20 ffff8880a6632c00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a06e5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a06e5a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a06e5b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff8880a06e5b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a06e5c00: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Node 0 Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB