drivers/cpufreq/pcc-cpufreq.c: avoid NULL pointer dereference

e71f5cc4 · Naga Chumbalkar <[email protected]> · 2011-09-14 16:22:23 -07:00

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 <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Len Brown <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: e71f5cc402ecb42b407ae52add7b173bf1c53daa
Parents: 88cee8fd

Changes

1 files changed · +3 −0

File	Status	Add	Del	Content
drivers/cpufreq/pcc-cpufreq.c	modified	+3	−0	View file

drivers/cpufreq/pcc-cpufreq.c

View file

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 @@ static int pcc_get_offset(int cpu)
 	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;