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cpumask: fix bug in use cpumask_var_t in irq_desc

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Impact: fix bug where new irq_desc uses old cpumask pointers which are freed.

As Yinghai pointed out, init_copy_one_irq_desc() copies the old desc to
the new desc overwriting the cpumask pointers.  Since the old_desc and
the cpumask pointers are freed, then memory corruption will occur if
these old pointers are used.

Move the allocation of these pointers to after the copy.

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Yinghai Lu <yinghai@kernel.org>
This commit is contained in:
Mike Travis 2009-01-10 21:58:09 -08:00 • committed by Ingo Molnar
parent 651f8118cf
commit 802bf931f2
3 changed files with 16 additions and 14 deletions
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9
include/linux/irq.h
View file

@ -426,15 +426,18 @@ extern int set_irq_msi(unsigned int irq, struct msi_desc *entry);
/**
* init_alloc_desc_masks - allocate cpumasks for irq_desc
* @desc: pointer to irq_desc struct
* @cpu: cpu which will be handling the cpumasks
* @boot: true if need bootmem
*
* Allocates affinity and pending_mask cpumask if required.
* Returns true if successful (or not required).
* Side effect: affinity has all bits set, pending_mask has all bits clear.
*/
static inline bool init_alloc_desc_masks(struct irq_desc *desc, int node,
static inline bool init_alloc_desc_masks(struct irq_desc *desc, int cpu,
bool boot)
{
int node;
if (boot) {
alloc_bootmem_cpumask_var(&desc->affinity);
cpumask_setall(desc->affinity);
@ -446,6 +449,8 @@ static inline bool init_alloc_desc_masks(struct irq_desc *desc, int node,
return true;
}
node = cpu_to_node(cpu);
if (!alloc_cpumask_var_node(&desc->affinity, GFP_ATOMIC, node))
return false;
cpumask_setall(desc->affinity);
@ -484,7 +489,7 @@ static inline void init_copy_desc_masks(struct irq_desc *old_desc,
#else /* !CONFIG_SMP */
static inline bool init_alloc_desc_masks(struct irq_desc *desc, int node,
static inline bool init_alloc_desc_masks(struct irq_desc *desc, int cpu,
bool boot)
{
return true;