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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 ffff8880135e0000 by task syz-executor.3/18709

CPU: 1 PID: 18709 Comm: syz-executor.3 Not tainted 5.10.0-rc6-next-20201201-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_released+0x25/0x2d0 mm/mmap_lock.c:185
 __mmap_lock_trace_released include/linux/mmap_lock.h:42 [inline]
 mmap_read_unlock include/linux/mmap_lock.h:144 [inline]
 maybe_unlock_mmap_for_io mm/internal.h:425 [inline]
 fault_dirty_shared_page+0x37a/0x400 mm/memory.c:2770
 do_shared_fault mm/memory.c:4097 [inline]
 do_fault mm/memory.c:4149 [inline]
 handle_pte_fault mm/memory.c:4385 [inline]
 __handle_mm_fault mm/memory.c:4520 [inline]
 handle_mm_fault+0x3127/0x55d0 mm/memory.c:4618
 do_user_addr_fault+0x570/0xc50 arch/x86/mm/fault.c:1398
 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: 0033:0x403a27
Code: 00 00 00 48 83 ec 08 48 8b 15 75 19 2b 01 48 8b 05 66 19 2b 01 48 39 d0 48 8d 8a 00 00 00 01 72 17 48 39 c8 73 12 48 8d 50 04 <89> 38 48 89 15 48 19 2b 01 48 83 c4 08 c3 48 89 c6 bf b0 2b 4d 00
RSP: 002b:00007ffea6da0d70 EFLAGS: 00010287
RAX: 0000001b30d21000 RBX: 000000000119c008 RCX: 0000001b31d20000
RDX: 0000001b30d21004 RSI: 0000000000000000 RDI: 00000000e64b494f
RBP: 00007fd227de1008 R08: 0000000000004ba0 R09: 00000000e64b494f
R10: 00000000e64b4953 R11: 0000000000000246 R12: 00000000000001db
R13: 00007fd227de1000 R14: 0000000000000553 R15: 0000000025d0617b

Allocated by task 18712:
 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+0xe3b/0x38e0 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 18710:
 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:172 [inline]
 exit_to_user_mode_prepare+0x1f0/0x200 kernel/entry/common.c:199
 syscall_exit_to_user_mode+0x36/0x260 kernel/entry/common.c:277
 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:3531
 drop_sysctl_table+0x3c0/0x4e0 fs/proc/proc_sysctl.c:1643
 unregister_sysctl_table fs/proc/proc_sysctl.c:1681 [inline]
 unregister_sysctl_table+0xbd/0x190 fs/proc/proc_sysctl.c:1656
 neigh_sysctl_unregister+0x5b/0x80 net/core/neighbour.c:3716
 addrconf_ifdown.isra.0+0xf8d/0x1590 net/ipv6/addrconf.c:3846
 addrconf_notify+0x55c/0x23f0 net/ipv6/addrconf.c:3628
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2035
 call_netdevice_notifiers_extack net/core/dev.c:2047 [inline]
 call_netdevice_notifiers net/core/dev.c:2061 [inline]
 rollback_registered_many+0x92e/0x14c0 net/core/dev.c:9472
 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10691
 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10690
 ip_tunnel_delete_nets+0x3eb/0x5b0 net/ipv4/ip_tunnel.c:1116
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

The buggy address belongs to the object at ffff8880135e0000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
 1024-byte region [ffff8880135e0000, ffff8880135e0400)
The buggy address belongs to the page:
page:00000000102d902a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x135e0
head:00000000102d902a order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 ffffea00006ca000 0000000500000005 ffff888010041140
raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880135dff00: 00 fc fc fc fc 00 fc fc fc fc fa fc fc fc fc 00
 ffff8880135dff80: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc fc fc
>ffff8880135e0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880135e0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880135e0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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