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| author | Thomas Gleixner <tglx@linutronix.de> | 2008-07-28 01:47:12 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-28 19:31:58 +0400 |
| commit | b032bf70df2e43149ce2b4e9a865b076c6140753 (patch) | |
| tree | ba022a0bc85598a29e21b7aa3f101c8043c24024 /drivers/acpi/processor_idle.c | |
| parent | 9ffc1699e36abd5baee188c8e36b1bb27d0d4278 (diff) | |
| download | linux-b032bf70df2e43149ce2b4e9a865b076c6140753.tar.xz | |
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 <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/acpi/processor_idle.c')
| -rw-r--r-- | drivers/acpi/processor_idle.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index b7f2963693a7..283c08f5f4d4 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1332,9 +1332,15 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) if (!pr->flags.power_setup_done) return -ENODEV; - /* Fall back to the default idle loop */ - pm_idle = pm_idle_save; - synchronize_sched(); /* Relies on interrupts forcing exit from idle. */ + /* + * Fall back to the default idle loop, when pm_idle_save had + * been initialized. + */ + if (pm_idle_save) { + pm_idle = pm_idle_save; + /* Relies on interrupts forcing exit from idle. */ + synchronize_sched(); + } pr->flags.power = 0; result = acpi_processor_get_power_info(pr); @@ -1896,7 +1902,8 @@ int acpi_processor_power_exit(struct acpi_processor *pr, /* Unregister the idle handler when processor #0 is removed. */ if (pr->id == 0) { - pm_idle = pm_idle_save; + if (pm_idle_save) + pm_idle = pm_idle_save; /* * We are about to unload the current idle thread pm callback |