| From e71f5cc402ecb42b407ae52add7b173bf1c53daa Mon Sep 17 00:00:00 2001 |
| From: Naga Chumbalkar <nagananda.chumbalkar@hp.com> |
| Date: Wed, 14 Sep 2011 16:22:23 -0700 |
| Subject: drivers/cpufreq/pcc-cpufreq.c: avoid NULL pointer dereference |
| |
| From: Naga Chumbalkar <nagananda.chumbalkar@hp.com> |
| |
| commit e71f5cc402ecb42b407ae52add7b173bf1c53daa upstream. |
| |
| 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> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/cpufreq/pcc-cpufreq.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- 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; |
