tracefs/eventfs: Free top level files on removal

When an instance is removed, the top level files of the eventfs directory
are not cleaned up. Call the eventfs_remove() on each of the entries to
free them.

This was found via kmemleak:

unreferenced object 0xffff8881047c1280 (size 96):
  comm "mkdir", pid 924, jiffies 4294906489 (age 2013.077s)
  hex dump (first 32 bytes):
    18 31 ed 03 81 88 ff ff 00 31 09 24 81 88 ff ff  .1.......1.$....
    00 00 00 00 00 00 00 00 98 19 7c 04 81 88 ff ff  ..........|.....
  backtrace:
    [<000000000fa46b4d>] kmalloc_trace+0x2a/0xa0
    [<00000000e729cd0c>] eventfs_prepare_ef.constprop.0+0x3a/0x160
    [<000000009032e6a8>] eventfs_add_events_file+0xa0/0x160
    [<00000000fe968442>] create_event_toplevel_files+0x6f/0x130
    [<00000000e364d173>] event_trace_add_tracer+0x14/0x140
    [<00000000411840fa>] trace_array_create_dir+0x52/0xf0
    [<00000000967804fa>] trace_array_create+0x208/0x370
    [<00000000da505565>] instance_mkdir+0x6b/0xb0
    [<00000000dc1215af>] tracefs_syscall_mkdir+0x5b/0x90
    [<00000000a8aca289>] vfs_mkdir+0x272/0x380
    [<000000007709b242>] do_mkdirat+0xfc/0x1d0
    [<00000000c0b6d219>] __x64_sys_mkdir+0x78/0xa0
    [<0000000097b5dd4b>] do_syscall_64+0x3f/0x90
    [<00000000a3f00cfa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
unreferenced object 0xffff888103ed3118 (size 8):
  comm "mkdir", pid 924, jiffies 4294906489 (age 2013.077s)
  hex dump (first 8 bytes):
    65 6e 61 62 6c 65 00 00                          enable..
  backtrace:
    [<0000000010f75127>] __kmalloc_node_track_caller+0x51/0x160
    [<000000004b3eca91>] kstrdup+0x34/0x60
    [<0000000050074d7a>] eventfs_prepare_ef.constprop.0+0x53/0x160
    [<000000009032e6a8>] eventfs_add_events_file+0xa0/0x160
    [<00000000fe968442>] create_event_toplevel_files+0x6f/0x130
    [<00000000e364d173>] event_trace_add_tracer+0x14/0x140
    [<00000000411840fa>] trace_array_create_dir+0x52/0xf0
    [<00000000967804fa>] trace_array_create+0x208/0x370
    [<00000000da505565>] instance_mkdir+0x6b/0xb0
    [<00000000dc1215af>] tracefs_syscall_mkdir+0x5b/0x90
    [<00000000a8aca289>] vfs_mkdir+0x272/0x380
    [<000000007709b242>] do_mkdirat+0xfc/0x1d0
    [<00000000c0b6d219>] __x64_sys_mkdir+0x78/0xa0
    [<0000000097b5dd4b>] do_syscall_64+0x3f/0x90
    [<00000000a3f00cfa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Link: https://lore.kernel.org/linux-trace-kernel/20230907175859.6fedbaa2@gandalf.local.home



Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 5bdcd5f5 eventfs: ("Implement removal of meta data from eventfs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>