audit: track the owner of the command mutex ourselves

Evidently the __mutex_owner() function was never intended for use
outside the core mutex code, so build a thing locking wrapper around
the mutex code which allows us to track the mutex owner.

One, arguably positive, side effect is that this allows us to hide
the audit_cmd_mutex inside of kernel/audit.c behind the lock/unlock
functions.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/audit.h b/kernel/audit.h
index af5bc59487ed..214e14948370 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -341,4 +341,5 @@ extern struct list_head *audit_killed_trees(void);
 #define audit_filter_inodes(t,c) AUDIT_DISABLED
 #endif
 
-extern struct mutex audit_cmd_mutex;
+extern void audit_ctl_lock(void);
+extern void audit_ctl_unlock(void);