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Commit e71f5cc4 authored by Naga Chumbalkar's avatar Naga Chumbalkar Committed by Linus Torvalds
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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: default avatarNaga 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 88cee8fd

drivers/cpufreq/pcc-cpufreq.c

+3 −0
Original line number Diff line number Diff line
@@ -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;