From b032bf70df2e43149ce2b4e9a865b076c6140753 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 27 Jul 2008 23:47:12 +0200 Subject: ACPI/CPUIDLE: prevent setting pm_idle to NULL pm_idle_save resp. pm_idle_old can be NULL when the restore code in acpi_processor_cst_has_changed() resp. cpuidle_uninstall_idle_handler() is called. This can set pm_idle unconditinally to NULL, which causes the kernel to panic when calling pm_idle in the x86 idle code. This was covered by an extra check for !pm_idle in the x86 idle code, which was removed during the x86 idle code refactoring. Instead of restoring the pm_idle check in the x86 code prevent the acpi/cpuidle code to set pm_idle to NULL. Reported by: Dhaval Giani http://lkml.org/lkml/2008/7/2/309 Based on a debug patch from Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Linus Torvalds --- drivers/cpuidle/cpuidle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 5405769020a1..5ce07b517c58 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -94,7 +94,7 @@ void cpuidle_install_idle_handler(void) */ void cpuidle_uninstall_idle_handler(void) { - if (enabled_devices && (pm_idle != pm_idle_old)) { + if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) { pm_idle = pm_idle_old; cpuidle_kick_cpus(); } -- cgit v1.2.3