drivers/cpufreq/pcc-cpufreq.c: avoid NULL pointer dereference
per_cpu(processors, n) can be NULL, resulting in:
Loading CPUFreq modules[ 437.661360] BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa0434314>] pcc_cpufreq_cpu_init+0x74/0x220 [pcc_cpufreq]
It's better to avoid the oops by failing the driver, and allowing the
system to boot.
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/cpufreq/pcc-cpufreq.c b/drivers/cpufreq/pcc-cpufreq.c
index 7b0603e..cdc02ac 100644
--- a/drivers/cpufreq/pcc-cpufreq.c
+++ b/drivers/cpufreq/pcc-cpufreq.c
@@ -261,6 +261,9 @@
pr = per_cpu(processors, cpu);
pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
+ if (!pr)
+ return -ENODEV;
+
status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
if (ACPI_FAILURE(status))
return -ENODEV;