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Commit 67992582 authored by Tarun Karra's avatar Tarun Karra
Browse files

msm: kgsl: Fix context timeline show from accessing uninitialized variables 



kgsl_sync_timeline_value_str() could be called at the same time as
kgsl_sync_timeline_create(). If kgsl_sync_timeline_value_str() gets
called just after timeline is created but before other variables of
struct kgsl_sync_timeline are initialized, we could be accessing
uninitialized variables in kgsl_sync_timeline_value_str() leading to
kernel panic. If device pointer is NULL in kgsl_sync_timeline_value_str(),
the context timeline is not fully initialized yet. Report the queued and
retired timestamp of this context as 0, because the context and timeline
are just getting initialized.

Change-Id: I288a3b936da5c5900c8eb7eb50988a971dd7a432
Signed-off-by: default avatarTarun Karra <tkarra@codeaurora.org>
parent 50e0173f

drivers/gpu/msm/kgsl_sync.c

+13 −3
Original line number Diff line number Diff line
@@ -241,8 +241,12 @@ static unsigned int kgsl_sync_get_timestamp( 
	struct kgsl_sync_timeline *ktimeline, enum kgsl_timestamp_type type)

{

	unsigned int ret = 0;

	struct kgsl_context *context;



	if (ktimeline->device == NULL)

		return 0;



	struct kgsl_context *context = kgsl_context_get(ktimeline->device,

	context = kgsl_context_get(ktimeline->device,

			ktimeline->context_id);



	if (context)
@@ -257,16 +261,22 @@ static void kgsl_sync_timeline_value_str(struct sync_timeline *sync_timeline, 
{

	struct kgsl_sync_timeline *ktimeline =

		(struct kgsl_sync_timeline *) sync_timeline;



	/*

	 * This callback can be called before the device and spinlock are

	 * initialized in struct kgsl_sync_timeline. kgsl_sync_get_timestamp()

	 * will check if device is NULL and return 0. Queued and retired

	 * timestamp of the context will be reported as 0, which is correct

	 * because the context and timeline are just getting initialized.

	 */

	unsigned int timestamp_retired = kgsl_sync_get_timestamp(ktimeline,

		KGSL_TIMESTAMP_RETIRED);

	unsigned int timestamp_queued = kgsl_sync_get_timestamp(ktimeline,

		KGSL_TIMESTAMP_QUEUED);



	spin_lock(&ktimeline->lock);

	snprintf(str, size, "%u queued:%u retired:%u",

		ktimeline->last_timestamp,

		timestamp_queued, timestamp_retired);

	spin_unlock(&ktimeline->lock);

}



static void kgsl_sync_pt_value_str(struct sync_pt *sync_pt,