lkdtm: avoid calling lkdtm_do_action() with spinlock held

lkdtm_do_action() may call sleeping functions like kmalloc(), so do not
call it with spin lock held.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 150cd7061b80..28adefe70f96 100644
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -354,6 +354,7 @@ static void lkdtm_do_action(enum ctype which)
 static void lkdtm_handler(void)
 {
         unsigned long flags;
+        bool do_it = false;
 
         spin_lock_irqsave(&count_lock, flags);
         count--;
@@ -361,10 +362,13 @@ static void lkdtm_handler(void)
                         cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 
         if (count == 0) {
-                lkdtm_do_action(cptype);
+                do_it = true;
                 count = cpoint_count;
         }
         spin_unlock_irqrestore(&count_lock, flags);
+
+        if (do_it)
+                lkdtm_do_action(cptype);
 }
 
 static int lkdtm_register_cpoint(enum cname which)