From: Eli Cohen <[email protected]>
When calling irq_set_affinity_notifier() with NULL at the notify
argument, it will cause freeing of the glue pointer in the
corresponding array entry but will leave the pointer in the array. A
subsequent call to free_irq_cpu_rmap() will try to free this entry again
leading to possible use after free.
Fix that by setting NULL to the array entry and checking that we have
non-zero at the array entry when iterating over the array in
free_irq_cpu_rmap().
Fixes: c39649c331c7 ("lib: cpu_rmap: CPU affinity reverse-mapping")
CC: Ben Hutchings <[email protected]>
CC: Andrew Morton <[email protected]>
CC: David Decotigny <[email protected]>
CC: Eric Dumazet <[email protected]>
CC: [email protected]
Signed-off-by: Eli Cohen <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>
---
lib/cpu_rmap.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c
index f08d9c56f712..e77f12bb3c77 100644
--- a/lib/cpu_rmap.c
+++ b/lib/cpu_rmap.c
@@ -232,7 +232,8 @@ void free_irq_cpu_rmap(struct cpu_rmap *rmap)
for (index = 0; index < rmap->used; index++) {
glue = rmap->obj[index];
- irq_set_affinity_notifier(glue->notify.irq, NULL);
+ if (glue)
+ irq_set_affinity_notifier(glue->notify.irq, NULL);
}
cpu_rmap_put(rmap);
@@ -268,6 +269,7 @@ static void irq_cpu_rmap_release(struct kref *ref)
container_of(ref, struct irq_glue, notify.kref);
cpu_rmap_put(glue->rmap);
+ glue->rmap->obj[glue->index] = NULL;
kfree(glue);
}
@@ -297,6 +299,7 @@ int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq)
rc = irq_set_affinity_notifier(irq, &glue->notify);
if (rc) {
cpu_rmap_put(glue->rmap);
+ rmap->obj[glue->index] = NULL;
kfree(glue);
}
return rc;
--
2.39.1