================================================================== 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 ffff888078976800 by task syz-executor.2/8503 CPU: 0 PID: 8503 Comm: syz-executor.2 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_write_unlock include/linux/mmap_lock.h:105 [inline] dup_mmap kernel/fork.c:605 [inline] dup_mm+0xe89/0x1380 kernel/fork.c:1360 copy_mm kernel/fork.c:1416 [inline] copy_process+0x2a1e/0x6fb0 kernel/fork.c:2098 kernel_clone+0xe7/0xab0 kernel/fork.c:2463 __do_sys_clone+0xc8/0x110 kernel/fork.c:2580 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c44a Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10 00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc 00 00 RSP: 002b:00007ffdb59a2810 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffdb59a2810 RCX: 000000000045c44a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffdb59a2850 R08: 0000000000000001 R09: 000000000257d940 R10: 000000000257dc10 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffdb59a28a0 Allocated by task 1091: 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 1090: 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 The buggy address belongs to the object at ffff888078976800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of 1024-byte region [ffff888078976800, ffff888078976c00) The buggy address belongs to the page: page:000000005e021f64 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78974 head:000000005e021f64 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: ffff888078976700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888078976780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888078976800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888078976880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888078976900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================