From 6ea24f9ad18c65cc179593b5cc2a88cdadf8cc0c Mon Sep 17 00:00:00 2001
From: Steven Rostedt <rostedt@goodmis.org>
Date: Sun, 30 Jul 2006 03:03:38 -0700
Subject: [PATCH] [PATCH] fix bad macro param in timer.c
We have
#define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK
and it's used via
list = varray[i + 1]->vec + (INDEX(i + 1));
So, due to underparenthesisation, this INDEX(i+1) is now a ... (TVR_BITS + i
+ 1 * TVN_BITS)) ...
So this bugfix changes behaviour. It worked before by sheer luck:
"If i was anything but 0, it was broken. But this was only used by
s390 and arm. Since it was for the next interrupt, could that next
interrupt be a problem (going into the second cascade)? But it was
probably seldom wrong. That is, this would fail if the next
interrupt was in the second cascade, and was wrapped. Which may
never of happened. Also if it did happen, it would have just missed
the interrupt.
If an interrupt was missed, and no one was there to miss it, was it
really missed :-)"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/timer.c b/kernel/timer.c
index ee319fc69f40d..726caf9a0a69c 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -408,7 +408,7 @@ static int cascade(tvec_base_t *base, tvec_t *tv, int index)
* This function cascades all vectors and executes all expired timer
* vectors.
*/
-#define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK
+#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
static inline void __run_timers(tvec_base_t *base)
{
--
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