From: Zachary Amsden Date: Sat, 20 May 2006 22:00:24 +0000 (-0700) Subject: [PATCH] Fix a NO_IDLE_HZ timer bug X-Git-Tag: v2.6.17-rc5~44 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0662b71322e211dba9a4bc0e6fbca7861a2b5a7d;p=pandora-kernel.git [PATCH] Fix a NO_IDLE_HZ timer bug Under certain timing conditions, a race during boot occurs where timer ticks are being processed on remote CPUs. The remote timer ticks can increment jiffies, and if this happens during a window when a timeout is very close to expiring but a local tick has not yet been delivered, you can end up with 1) No softirq pending 2) A local timer wheel which is not synced to jiffies 3) No high resolution timer active 4) A local timer which is supposed to fire before the current jiffies value. In this circumstance, the comparison in next_timer_interrupt overflows, because the base of the comparison for high resolution timers is jiffies, but for the softirq timer wheel, it is relative the the current base of the wheel (jiffies_base). Signed-off-by: Zachary Amsden Cc: Martin Schwidefsky Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed