From: Thomas Gleixner Date: Tue, 29 May 2007 21:47:39 +0000 (+0200) Subject: NOHZ: prevent multiplication overflow - stop timer for huge timeouts X-Git-Tag: v2.6.22-rc4~95 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eaad084bb0f3a6259e56400cd45d061dbf040600;p=pandora-kernel.git NOHZ: prevent multiplication overflow - stop timer for huge timeouts get_next_timer_interrupt() returns a delta of (LONG_MAX > 1) in case there is no timer pending. On 64 bit machines this results in a multiplication overflow in tick_nohz_stop_sched_tick(). Reported by: Dave Miller Make the return value a constant and limit the return value to a 32 bit value. When the max timeout value is returned, we can safely stop the tick timer device. The max jiffies delta results in a 12 days timeout for HZ=1000. In the long term the get_next_timer_interrupt() code needs to be reworked to return ktime instead of jiffies, but we have to wait until the last users of the original NO_IDLE_HZ code are converted. Signed-off-by: Thomas Gleixner Acked-off-by: David S. Miller Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed