component: fix crash on x86_64 with hda audio drivers
Maarten reports that the addition of releasing match data to the
component helper results in a general protection fault on x86_64.
This is caused by the devm resources being freed in reverse order
to their allocation, which caused a use-after-free of the match
array.
Switch the match array to be a more conventional kmalloc/kfree()
affair, explicitly freeing it along with the parent match data
structure.
Reported-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: ce657b1cddf1 ("component: add support for releasing match data")
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/base/component.c b/drivers/base/component.c
index 89f5cf68..05cd26c 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -206,6 +206,8 @@
if (mc->release)
mc->release(master, mc->data);
}
+
+ kfree(match->compare);
}
static void devm_component_match_release(struct device *dev, void *res)
@@ -221,14 +223,14 @@
if (match->alloc == num)
return 0;
- new = devm_kmalloc_array(dev, num, sizeof(*new), GFP_KERNEL);
+ new = kmalloc_array(num, sizeof(*new), GFP_KERNEL);
if (!new)
return -ENOMEM;
if (match->compare) {
memcpy(new, match->compare, sizeof(*new) *
min(match->num, num));
- devm_kfree(dev, match->compare);
+ kfree(match->compare);
}
match->compare = new;
match->alloc = num;