linux-kernel - [Patch] lkdtm: avoid calling lkdtm_do

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Date:	Sat, 28 Jan 2012 20:52:47 +0800
From:	Cong Wang <xiyou.wangcong@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Prarit Bhargava <prarit@...hat.com>,
	WANG Cong <xiyou.wangcong@...il.com>,
	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <greg@...ah.com>
Subject: [Patch] lkdtm: avoid calling lkdtm_do_action() with spin lock held

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

Cc: Prarit Bhargava <prarit@...hat.com>
Signed-off-by: WANG Cong <xiyou.wangcong@...il.com>

---
diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 150cd70..28adefe 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)
--
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