From: john stultz Date: Fri, 1 May 2009 20:10:25 +0000 (-0700) Subject: clockevents: prevent endless loop in tick_handle_periodic() X-Git-Tag: v2.6.30-rc5~31^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=74a03b69d1b5ce00a568e142ca97e76b7f5239c6;p=pandora-kernel.git clockevents: prevent endless loop in tick_handle_periodic() tick_handle_periodic() can lock up hard when a one shot clock event device is used in combination with jiffies clocksource. Avoid an endless loop issue by requiring that a highres valid clocksource be installed before we call tick_periodic() in a loop when using ONESHOT mode. The result is we will only increment jiffies once per interrupt until a continuous hardware clocksource is available. Without this, we can run into a endless loop, where each cycle through the loop, jiffies is updated which increments time by tick_period or more (due to clock steering), which can cause the event programming to think the next event was before the newly incremented time and fail causing tick_periodic() to be called again and the whole process loops forever. [ Impact: prevent hard lock up ] Signed-off-by: John Stultz Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner Cc: stable@kernel.org --- Reading git-diff-tree failed