clocksource: Make watchdog robust vs. interruption
commitb63010f54cdcb456c3a29e242a0769e5b412d785
authorThomas Gleixner <tglx@linutronix.de>
Thu, 16 Jun 2011 14:22:08 +0000 (16 16:22 +0200)
committerGreg Kroah-Hartman <gregkh@suse.de>
Wed, 13 Jul 2011 03:29:23 +0000 (13 05:29 +0200)
treedefd97a8f023016d492b312a4d8406ac327ab27d
parent86df348681f6fe4c63a1511634ca50e148fb442f
clocksource: Make watchdog robust vs. interruption

commit b5199515c25cca622495eb9c6a8a1d275e775088 upstream.

The clocksource watchdog code is interruptible and it has been
observed that this can trigger false positives which disable the TSC.

The reason is that an interrupt storm or a long running interrupt
handler between the read of the watchdog source and the read of the
TSC brings the two far enough apart that the delta is larger than the
unstable treshold. Move both reads into a short interrupt disabled
region to avoid that.

Reported-and-tested-by: Vernon Mauery <vernux@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
include/linux/clocksource.h
kernel/time/clocksource.c