[patch 06/46] Fix timeout overflow with jiffies

Thomas Gleixner
2007-01-23T22:12:32Z

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From: Ingo Molnar <mingo@elte.hu>

Prevent timeout overflow if timer ticks are behind jiffies (due to high
softirq load or due to dyntick), by limiting the valid timeout range to
MAX_LONG/2.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

include/linux/jiffies.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6.20-rc4-mm1-bo/include/linux/jiffies.h
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/include/linux/jiffies.h
+++ linux-2.6.20-rc4-mm1-bo/include/linux/jiffies.h
@@ -142,13 +142,13 @@ static inline u64 get_jiffies_64(void)
*
* And some not so obvious.
*
- * Note that we don't want to return MAX_LONG, because
+ * Note that we don't want to return LONG_MAX, because
* for various timeout reasons we often end up having
* to wait "jiffies+1" in order to guarantee that we wait
* at _least_ "jiffies" - so "jiffies+1" had better still
* be positive.
*/
-#define MAX_JIFFY_OFFSET ((~0UL >> 1)-1)
+#define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1)

/*
* We want to do realistic conversions of time so we need to use the same

--