[PATCH 3.18 58/60] tracing: Fix kmemleak in instance_rmdir

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chunyu Hu <chuhu@xxxxxxxxxx>

commit db9108e054700c96322b0f0028546aa4e643cf0b upstream.

Hit the kmemleak when executing instance_rmdir, it forgot releasing
mem of tracing_cpumask. With this fix, the warn does not appear any
more.

unreferenced object 0xffff93a8dfaa7c18 (size 8):
  comm "mkdir", pid 1436, jiffies 4294763622 (age 9134.308s)
  hex dump (first 8 bytes):
    ff ff ff ff ff ff ff ff                          ........
  backtrace:
    [<ffffffff88b6567a>] kmemleak_alloc+0x4a/0xa0
    [<ffffffff8861ea41>] __kmalloc_node+0xf1/0x280
    [<ffffffff88b505d3>] alloc_cpumask_var_node+0x23/0x30
    [<ffffffff88b5060e>] alloc_cpumask_var+0xe/0x10
    [<ffffffff88571ab0>] instance_mkdir+0x90/0x240
    [<ffffffff886e5100>] tracefs_syscall_mkdir+0x40/0x70
    [<ffffffff886565c9>] vfs_mkdir+0x109/0x1b0
    [<ffffffff8865b1d0>] SyS_mkdir+0xd0/0x100
    [<ffffffff88403857>] do_syscall_64+0x67/0x150
    [<ffffffff88b710e7>] return_from_SYSCALL_64+0x0/0x6a
    [<ffffffffffffffff>] 0xffffffffffffffff

Link: http://lkml.kernel.org/r/1500546969-12594-1-git-send-email-chuhu@xxxxxxxxxx

Fixes: ccfe9e42e451 ("tracing: Make tracing_cpumask available for all instances")
Signed-off-by: Chunyu Hu <chuhu@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/trace/trace.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6405,6 +6405,7 @@ static int instance_delete(const char *n
 	debugfs_remove_recursive(tr->dir);
 	free_trace_buffers(tr);
 
+	free_cpumask_var(tr->tracing_cpumask);
 	kfree(tr->name);
 	kfree(tr);