Skip to contentSkip to conversation

coresight: cti: Add const to con_groups allocation type

PATCH In review Kees Cook 3 participants 3 messages Sep 17 – Sep 28

Subsystems (2)
Arm/CoreSight framework and drivers Hardware tracing facilities
lore
Share & tools
lore

Kees Cook

author
#0 lore raw

PATCH 1/1 coresight: cti: Add const to con_groups allocation type

From: Kees Cook <[email protected]>

In preparation for making the devm_kmalloc family of allocators type aware, we need to make sure that the returned type from the allocation matches the type of the variable being assigned. (Before, the allocator would always return "void *", which can be implicitly cast to any pointer type.)

The assigned type is "const struct attribute_group **", but the converted allocation type would be "struct attribute_group **", which is the same type without the const qualifier. As there is no general way to safely add const qualifiers, take the size from the assignment target instead. No change in allocation size results.

Build tested ARCH=arm64 allmodconfig with GCC aarch64-linux-gnu 16.1.0:
drivers/hwtracing/coresight/coresight-cti-sysfs.o

Assisted-by LLM coccinelle
Signed-off-by Kees Cook <[email protected]>

---
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: James Clark <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>

---
 drivers/hwtracing/coresight/coresight-cti-sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/hwtracing/coresight/coresight-cti-sysfs.c +1 -1
index 3fe2c916d228..2ed5d8eb1dda 100644
@@ -1132,7 +1132,7 @@ static int cti_create_cons_groups(struct device *dev, struct cti_device *ctidev)
 	/* nr groups = dynamic + static + NULL terminator */
 	nr_groups = ctidev->nr_trig_con + CORESIGHT_CTI_STATIC_GROUPS_MAX;
 	ctidev->con_groups = devm_kcalloc(dev, nr_groups,
-					  sizeof(struct attribute_group *),
+					  sizeof(*ctidev->con_groups),
 					  GFP_KERNEL);
 	if (!ctidev->con_groups)
 		return -ENOMEM;
Signature · 1 line
2.34.1
reviewer Reviewed-by on v1 1/1
#1 lore raw
Reviewed-by Mike Leach <[email protected]>
Quoted 44 lines · Kees Cook

From: Kees Cook <[email protected]>

In preparation for making the devm_kmalloc family of allocators type aware, we need to make sure that the returned type from the allocation matches the type of the variable being assigned. (Before, the allocator would always return "void *", which can be implicitly cast to any pointer type.)

The assigned type is "const struct attribute_group **", but the converted allocation type would be "struct attribute_group **", which is the same type without the const qualifier. As there is no general way to safely add const qualifiers, take the size from the assignment target instead. No change in allocation size results.

Build tested ARCH=arm64 allmodconfig with GCC aarch64-linux-gnu 16.1.0:
drivers/hwtracing/coresight/coresight-cti-sysfs.o

Assisted-by LLM coccinelle
Signed-off-by Kees Cook <[email protected]>

---
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: James Clark <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>

---
  drivers/hwtracing/coresight/coresight-cti-sysfs.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
drivers/hwtracing/coresight/coresight-cti-sysfs.c +1 -1
index 3fe2c916d228..2ed5d8eb1dda 100644
@@ -1132,7 +1132,7 @@ static int cti_create_cons_groups(struct device *dev, struct cti_device *ctidev)
  	/* nr groups = dynamic + static + NULL terminator */
  	nr_groups = ctidev->nr_trig_con + CORESIGHT_CTI_STATIC_GROUPS_MAX;
  	ctidev->con_groups = devm_kcalloc(dev, nr_groups,
-					  sizeof(struct attribute_group *),
+					  sizeof(*ctidev->con_groups),
  					  GFP_KERNEL);
  	if (!ctidev->con_groups)
  		return -ENOMEM;
reviewer Reviewed-by on v1 1/1
#2 lore raw
In reply to Kees Cook
Quoted 11 lines · Kees Cook

From: Kees Cook <[email protected]>

... As there is no general way to
safely add const qualifiers, take the size from the assignment target instead. No change in allocation size results.

Build tested ARCH=arm64 allmodconfig with GCC aarch64-linux-gnu 16.1.0:
drivers/hwtracing/coresight/coresight-cti-sysfs.o

Assisted-by LLM coccinelle
Signed-off-by Kees Cook <[email protected]>
Reviewed-by Leo Yan <[email protected]>