From: Steven Rostedt Date: Sun, 30 Jul 2006 10:03:38 +0000 (-0700) Subject: [PATCH] fix bad macro param in timer.c X-Git-Tag: v2.6.18-rc4~120 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6ea24f9ad18c65cc179593b5cc2a88cdadf8cc0c;p=linux-2.6 [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 Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/timer.c b/kernel/timer.c index ee319fc69f..726caf9a0a 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) {