[CPUFREQ] Fix use after free on governor restore
Currently on governer backup/restore path we storing governor's pointer. This is wrong because one may unload governor's module after cpu goes offline. As result use-after-free will take place on restored cpu. It is not easy to exploit this bug, but still we have to close this issue ASAP. Issue was introduced by following commit 084f3493 ##TESTCASE## #!/bin/sh -x modprobe acpi_cpufreq # Any non default governor, in may case it is "ondemand" modprobe cpufreq_ondemand echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor rmmod acpi_cpufreq rmmod cpufreq_ondemand modprobe acpi_cpufreq # << use-after-free here. Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Dave Jones <davej@redhat.com>
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