[PATCH] add_timer() of a pending timer is illegal

Andrew Morton · Linus Torvalds · commit 15d2bace5ec9 · 2005-10-30T17:37:21.000-08:00
In the recent timer rework we lost the check for an add_timer() of an
already-pending timer.  That check was useful for networking, so put it back.

Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Signed-off-by: Andrew Morton &lt;akpm@osdl.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@osdl.org&gt;
diff --git a/include/linux/timer.h b/include/linux/timer.h
@@ -78,8 +78,9 @@ extern unsigned long next_timer_interrupt(void);
  * Timers with an ->expired field in the past will be executed in the next
  * timer tick.
  */
-static inline void add_timer(struct timer_list * timer)
+static inline void add_timer(struct timer_list *timer)
 {
+	BUG_ON(timer_pending(timer));
 	__mod_timer(timer, timer->expires);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -78,8 +78,9 @@ extern unsigned long next_timer_interrupt(void);`
`78`	`78`	`* Timers with an ->expired field in the past will be executed in the next`
`79`	`79`	`* timer tick.`
`80`	`80`	`*/`
`81`		`-static inline void add_timer(struct timer_list * timer)`
	`81`	`+static inline void add_timer(struct timer_list *timer)`
`82`	`82`	`{`
	`83`	`+ BUG_ON(timer_pending(timer));`
`83`	`84`	`__mod_timer(timer, timer->expires);`
`84`	`85`	`}`
`85`	`86`