[v4,02/15] drivers/firmware/sdei: Common block for failing path in sdei_event_create()

Commit Message

Gavin Shan July 30, 2020, 1:45 a.m. UTC

There are multiple calls of kfree(event) in the failing path of
sdei_event_create() to free the SDEI event. It means we need to
call it again when adding more code in the failing path. It's
prone to miss doing that and introduce memory leakage.

This introduces common block for failing path in sdei_event_create()
to resolve the issue. This shouldn't cause functional changes.

Signed-off-by: Gavin Shan <[e-mail]>
Reviewed-by: Jonathan Cameron <[e-mail]>
---
 drivers/firmware/arm_sdei.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

Comments

James Morse Sept. 18, 2020, 4:10 p.m. UTC | #1

Hi Gavin,

(Suject Nit: almost all of the commits to this file begin 'firmware: arm_sdei:')

On 30/07/2020 02:45, Gavin Shan wrote:
> There are multiple calls of kfree(event) in the failing path of
> sdei_event_create() to free the SDEI event.

> It means we need to
> call it again when adding more code in the failing path. It's
> prone to miss doing that and introduce memory leakage.

If there is another things that needs adding here, sure.
(otherwise there is no unwinding that needs to happen.)


> This introduces common block for failing path in sdei_event_create()
> to resolve the issue. This shouldn't cause functional changes.

Acked-by: James Morse <[e-mail]>



Thanks,

James

Patch

diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index be5367f839f2..67da02b3a06e 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -190,33 +190,31 @@  static struct sdei_event *sdei_event_create(u32 event_num,
 	lockdep_assert_held(&sdei_events_lock);
 
 	event = kzalloc(sizeof(*event), GFP_KERNEL);
-	if (!event)
-		return ERR_PTR(-ENOMEM);
+	if (!event) {
+		err = -ENOMEM;
+		goto fail;
+	}
 
 	INIT_LIST_HEAD(&event->list);
 	event->event_num = event_num;
 
 	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
 				      &result);
-	if (err) {
-		kfree(event);
-		return ERR_PTR(err);
-	}
+	if (err)
+		goto fail;
 	event->priority = result;
 
 	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
 				      &result);
-	if (err) {
-		kfree(event);
-		return ERR_PTR(err);
-	}
+	if (err)
+		goto fail;
 	event->type = result;
 
 	if (event->type == SDEI_EVENT_TYPE_SHARED) {
 		reg = kzalloc(sizeof(*reg), GFP_KERNEL);
 		if (!reg) {
-			kfree(event);
-			return ERR_PTR(-ENOMEM);
+			err = -ENOMEM;
+			goto fail;
 		}
 
 		reg->event_num = event_num;
@@ -231,8 +229,8 @@  static struct sdei_event *sdei_event_create(u32 event_num,
 
 		regs = alloc_percpu(struct sdei_registered_event);
 		if (!regs) {
-			kfree(event);
-			return ERR_PTR(-ENOMEM);
+			err = -ENOMEM;
+			goto fail;
 		}
 
 		for_each_possible_cpu(cpu) {
@@ -252,6 +250,10 @@  static struct sdei_event *sdei_event_create(u32 event_num,
 	spin_unlock(&sdei_list_lock);
 
 	return event;
+
+fail:
+	kfree(event);
+	return ERR_PTR(err);
 }
 
 static void sdei_event_destroy_llocked(struct sdei_event *event)