==================================================================
BUG: KASAN: use-after-free in strlcpy include/linux/string.h:355 [inline]
BUG: KASAN: use-after-free in kernfs_path_from_node_locked+0x9b3/0xc80 fs/kernfs/dir.c:138
Write of size 1 at addr ffff888016f70000 by task syz-executor.4/15668

CPU: 0 PID: 15668 Comm: syz-executor.4 Not tainted 5.10.0-rc5-next-20201126-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:396 [inline]
 kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/generic.c:180 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:186
 memcpy+0x39/0x60 mm/kasan/shadow.c:66
 strlcpy include/linux/string.h:355 [inline]
 kernfs_path_from_node_locked+0x9b3/0xc80 fs/kernfs/dir.c:138
 kernfs_path_from_node+0x3a/0x60 fs/kernfs/dir.c:217
 kernfs_path include/linux/kernfs.h:542 [inline]
 cgroup_path include/linux/cgroup.h:661 [inline]
 get_mm_memcg_path+0xb2/0xf0 mm/mmap_lock.c:130
 __mmap_lock_do_trace_start_locking+0x25/0x2d0 mm/mmap_lock.c:172
 __mmap_lock_trace_start_locking include/linux/mmap_lock.h:29 [inline]
 mmap_read_trylock include/linux/mmap_lock.h:135 [inline]
 do_user_addr_fault+0x638/0xc50 arch/x86/mm/fault.c:1339
 handle_page_fault arch/x86/mm/fault.c:1455 [inline]
 exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1511
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:580
RIP: 0033:0x436565
Code: c4 80 00 00 00 f3 c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 8b 05 2e 80 31 00 85 c0 0f 8e 85 00 00 00 48 c7 c0 f0 ff ff ff <c7> 05 01 39 27 01 00 00 00 00 64 48 8b 08 48 85 c9 74 0b 48 c7 81
RSP: 002b:00007ffcf1dacf08 EFLAGS: 00010202
RAX: fffffffffffffff0 RBX: 00007ffcf1dacf10 RCX: 00000000004185a3
RDX: 000000fef5eefc44 RSI: 0000000000000018 RDI: 0000000002c40c20
RBP: 00007ffcf1dacf50 R08: 0000000000000001 R09: 0000000002c40940
R10: 0000000002c40c10 R11: 0000000000000202 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffcf1dacfa0

Allocated by task 15666:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39
 kasan_set_track mm/kasan/common.c:47 [inline]
 set_alloc_info mm/kasan/common.c:405 [inline]
 ____kasan_kmalloc mm/kasan/common.c:436 [inline]
 ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:408
 kmalloc include/linux/slab.h:552 [inline]
 trace_mmap_lock_reg+0x196/0x550 mm/mmap_lock.c:58
 tracepoint_add_func+0x304/0x990 kernel/tracepoint.c:257
 tracepoint_probe_register_prio kernel/tracepoint.c:342 [inline]
 tracepoint_probe_register+0x9c/0xe0 kernel/tracepoint.c:362
 trace_event_reg+0x28f/0x350 kernel/trace/trace_events.c:305
 perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
 perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204
 perf_trace_init+0x176/0x240 kernel/trace/trace_event_perf.c:228
 perf_tp_event_init+0xa2/0x120 kernel/events/core.c:9590
 perf_try_init_event+0x12a/0x560 kernel/events/core.c:11058
 perf_init_event kernel/events/core.c:11110 [inline]
 perf_event_alloc.part.0+0xe04/0x38b0 kernel/events/core.c:11388
 perf_event_alloc kernel/events/core.c:11767 [inline]
 __do_sys_perf_event_open+0x72c/0x2cb0 kernel/events/core.c:11883
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 15664:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:47
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:358
 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:187 [inline]
 slab_free_hook mm/slub.c:1548 [inline]
 slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1586
 slab_free mm/slub.c:3157 [inline]
 kfree+0xe5/0x5c0 mm/slub.c:4156
 trace_mmap_lock_unreg+0xba/0x160 mm/mmap_lock.c:94
 tracepoint_remove_func kernel/tracepoint.c:306 [inline]
 tracepoint_probe_unregister+0x5b6/0x890 kernel/tracepoint.c:382
 trace_event_reg+0x181/0x350 kernel/trace/trace_events.c:309
 perf_trace_event_unreg.isra.0+0xac/0x250 kernel/trace/trace_event_perf.c:162
 perf_trace_destroy+0xb5/0xf0 kernel/trace/trace_event_perf.c:243
 _free_event+0x2ee/0x1300 kernel/events/core.c:4840
 put_event kernel/events/core.c:4934 [inline]
 perf_event_release_kernel+0xa24/0xe00 kernel/events/core.c:5049
 perf_release+0x33/0x40 kernel/events/core.c:5059
 __fput+0x283/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x190 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x1f0/0x200 kernel/entry/common.c:198
 syscall_exit_to_user_mode+0x36/0x260 kernel/entry/common.c:275
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Last call_rcu():
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39
 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:346
 kvfree_call_rcu+0x74/0x930 kernel/rcu/tree.c:3533
 neigh_destroy+0x3ff/0x5f0 net/core/neighbour.c:859
 neigh_release include/net/neighbour.h:425 [inline]
 neigh_cleanup_and_release+0x1fd/0x340 net/core/neighbour.c:104
 neigh_del net/core/neighbour.c:194 [inline]
 neigh_remove_one+0x3b1/0x440 net/core/neighbour.c:215
 neigh_forced_gc net/core/neighbour.c:244 [inline]
 neigh_alloc net/core/neighbour.c:391 [inline]
 ___neigh_create+0x1672/0x2540 net/core/neighbour.c:579
 ip6_finish_output2+0xdf8/0x16c0 net/ipv6/ip6_output.c:114
 __ip6_finish_output net/ipv6/ip6_output.c:143 [inline]
 __ip6_finish_output+0x447/0xab0 net/ipv6/ip6_output.c:128
 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x1db/0x520 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:441 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ndisc_send_skb+0xa69/0x1720 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x12e/0x700 net/ipv6/ndisc.c:702
 addrconf_rs_timer+0x3f2/0x820 net/ipv6/addrconf.c:3874
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1417
 expire_timers kernel/time/timer.c:1462 [inline]
 __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1731
 __run_timers kernel/time/timer.c:1712 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1744
 __do_softirq+0x2a0/0x9f6 kernel/softirq.c:298

The buggy address belongs to the object at ffff888016f70000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
 1024-byte region [ffff888016f70000, ffff888016f70400)
The buggy address belongs to the page:
page:00000000adb8a6aa refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16f70
head:00000000adb8a6aa order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010041140
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888016f6ff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888016f6ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888016f70000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888016f70080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888016f70100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================