intel_cacheinfo: potential NULL dereference?

From: Jiri Slaby
Date: Tue Jun 22 2010 - 07:18:45 EST


Hi,

commit 9350f982 changed the code so it looks like:
static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf,
const char *buf, size_t count,
unsigned int slot)
{
struct pci_dev *dev = this_leaf->l3->dev; <<1>>
int cpu = cpumask_first(to_cpumask(this_leaf->shared_cpu_map));
unsigned long val = 0;

#define SUBCACHE_MASK (3UL << 20)
#define SUBCACHE_INDEX 0xfff

if (!this_leaf->l3 || !this_leaf->l3->can_disable) <<2>>
return -EINVAL;

Stanse found, that this_leaf->l3 is dereferenced at <<1>>, but checked
for being NULL at <<2>>. Is the check superfluous or the dev assignment
should go after the check?

thanks,
--
js
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