Messages in this thread Patch in this message | | | Date | Thu, 23 Feb 2012 12:58:05 -0800 | From | "Paul E. McKenney" <> | Subject | [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() |
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The acpi_processor_cst_has_changed() function is invoked from a CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 even though the CPU being hotplugged is some other CPU. In addition, acpi_processor_cst_has_changed() invokes smp_processor_id() without protection, resulting in splats when onlining CPUs.
This commit therefore changes the smp_processor_id() to pr->id, as is used elsewhere in the code, for example, in acpi_processor_add().
This works for me, but I don't claim to understand ACPI.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 0e8e2de..9e57b06 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) * to make the code that updates C-States be called once. */ - if (smp_processor_id() == 0 && - cpuidle_get_driver() == &acpi_idle_driver) { + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { cpuidle_pause_and_lock(); /* Protect against cpu-hotplug */
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