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* acpi: Fix broken error check in map_processor()
@ 2016-09-23 15:08 ` Thomas Gleixner
  0 siblings, 0 replies; 6+ messages in thread
From: Thomas Gleixner @ 2016-09-23 15:08 UTC (permalink / raw)
  To: Dou Liyang
  Cc: cl, tj, mika.j.penttila, mingo, akpm, rjw, hpa, yasu.isimatu,
	isimatu.yasuaki, kamezawa.hiroyu, izumi.taku, gongzhaogang,
	len.brown, lenb, chen.tang, rafael, x86, linux-acpi,
	linux-kernel, linux-mm, Gu Zheng, Tang Chen, Zhu Guihua

map_processor() checks the cpuid value returned by acpi_map_cpuid() for -1
but acpi_map_cpuid() returns -EINVAL in case of error.

As a consequence the error is ignored and the following access into percpu
data with that negative cpuid results in a boot crash.

This happens always when NR_CPUS/nr_cpu_ids is smaller than the number of
processors listed in the ACPI tables.

Use a proper error check for id < 0 so the function returns instead of
trying to map CPU#(-EINVAL).

Reported-by: Ingo Molnar <mingo@kernel.org>
Fixes: dc6db24d2476 ("x86/acpi: Set persistent cpuid <-> nodeid mapping when booting")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/acpi/processor_core.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -284,7 +284,7 @@ EXPORT_SYMBOL_GPL(acpi_get_cpuid);
 static bool __init
 map_processor(acpi_handle handle, phys_cpuid_t *phys_id, int *cpuid)
 {
-	int type;
+	int type, id;
 	u32 acpi_id;
 	acpi_status status;
 	acpi_object_type acpi_type;
@@ -320,10 +320,11 @@ map_processor(acpi_handle handle, phys_c
 	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
 
 	*phys_id = __acpi_get_phys_id(handle, type, acpi_id, false);
-	*cpuid = acpi_map_cpuid(*phys_id, acpi_id);
-	if (*cpuid == -1)
-		return false;
+	id = acpi_map_cpuid(*phys_id, acpi_id);
 
+	if (id < 0)
+		return false;
+	*cpuid = id;
 	return true;
 }
 

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^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2016-09-24  0:06 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-09-23 15:08 acpi: Fix broken error check in map_processor() Thomas Gleixner
2016-09-23 15:08 ` Thomas Gleixner
2016-09-23 18:54 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2016-09-24  0:06 ` Rafael J. Wysocki
2016-09-24  0:06   ` Rafael J. Wysocki
2016-09-24  0:06   ` Rafael J. Wysocki

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