================================================================== 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 ffff88802ace9800 by task systemd-udevd/15066 CPU: 0 PID: 15066 Comm: systemd-udevd 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_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] do_user_addr_fault+0x795/0xc50 arch/x86/mm/fault.c:1419 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: 0033:0x7fb65be64ef0 Code: 5c f3 c3 0f 1f 80 00 00 00 00 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 eb e2 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 49 89 fd 53 48 89 f3 48 81 ec RSP: 002b:00007ffda35f5bd8 EFLAGS: 00010246 RAX: 00000000fbad8001 RBX: 00007ffda35f5df0 RCX: 0000000000000000 RDX: 00007ffda35f5d08 RSI: 00007fb65ca4938b RDI: 00007ffda35f5be0 RBP: 00007fb65ca4938b R08: 0000000000000000 R09: 0000000000000110 R10: 0000000000000522 R11: 00007fb65be74280 R12: 00007ffda35f5d08 R13: 00007ffda35f5e72 R14: 0000000000000000 R15: 000000000000000f Allocated by task 15067: 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 15064: 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 __call_rcu kernel/rcu/tree.c:2981 [inline] call_rcu+0xbb/0x760 kernel/rcu/tree.c:3056 sctp_transport_destroy net/sctp/transport.c:167 [inline] sctp_transport_put+0x11d/0x180 net/sctp/transport.c:326 sctp_association_free+0x4d4/0x7d0 net/sctp/associola.c:381 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:930 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1318 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline] sctp_do_sm+0x38b8/0x5120 net/sctp/sm_sideeffect.c:1156 sctp_assoc_bh_rcv+0x386/0x6c0 net/sctp/associola.c:1048 sctp_inq_push+0x1da/0x270 net/sctp/inqueue.c:80 sctp_backlog_rcv+0x19e/0x5c0 net/sctp/input.c:344 sk_backlog_rcv include/net/sock.h:1010 [inline] __release_sock+0x134/0x3a0 net/core/sock.c:2523 release_sock+0x54/0x1b0 net/core/sock.c:3053 sctp_close+0x447/0x940 net/sctp/socket.c:1519 inet_release+0x12e/0x280 net/ipv4/af_inet.c:431 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:475 __sock_release+0xcd/0x280 net/socket.c:596 sock_close+0x18/0x20 net/socket.c:1255 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xb89/0x29e0 kernel/exit.c:823 do_group_exit+0x125/0x310 kernel/exit.c:920 get_signal+0x3ec/0x2010 kernel/signal.c:2770 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811 handle_signal_work kernel/entry/common.c:144 [inline] exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x124/0x200 kernel/entry/common.c:198 syscall_exit_to_user_mode+0x36/0x260 kernel/entry/common.c:275 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Second to 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 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 devinet_sysctl_unregister net/ipv4/devinet.c:2623 [inline] inetdev_destroy net/ipv4/devinet.c:324 [inline] inetdev_event+0xd0e/0x15c0 net/ipv4/devinet.c:1598 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:9423 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10642 unregister_netdevice_many net/core/dev.c:10641 [inline] default_device_exit_batch+0x30c/0x3d0 net/core/dev.c:11125 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 ffff88802ace9800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of 1024-byte region [ffff88802ace9800, ffff88802ace9c00) The buggy address belongs to the page: page:0000000090f58935 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ace8 head:0000000090f58935 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010041140 raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88802ace9700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802ace9780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802ace9800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802ace9880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ace9900: fb fb 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