-
john stultz authored
Resolved differently upstream in commit 8cab02dc Ondrej Zary reported a suspend/resume hang with 2.6.31 in bug #14222. http://bugzilla.kernel.org/show_bug.cgi?id=14222 The hang was bisected to c7121843 however, that was really just the last straw that caused the issue. The problem was that on suspend, the PIT is removed as a clocksource, and was using the mult value essentially as a is_enabled() flag. The mult adjustments done in the commit above caused that usage to break, causing bad list manipulation and the oops. Further, on resume, the PIT clocksource is never restored, causing the system to run in a degraded mode with jiffies as the clocksource. This issue has since been resolved in 2.6.32-rc by commit 8cab02dc which removes the clocksource disabling on suspend. Testing shows no issues there. So the following patch rectifies the situation for 2.6.31 users of the PIT clocksource that use suspend and resume (which is probably not that many). Many thanks to Ondrej for helping narrow down what was happening, what caused it, and verifying the fix. --------------- Avoid using the unprotected clocksource.mult value as an "is_registered" flag, instead us an explicit flag variable. This avoids possible list corruption if the clocksource is double-unregistered. Also re-register the PIT clocksource on resume so folks don't have to use jiffies after suspend. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
112a62dd