drm/msm/a6xx: Fix kvzalloc vs state_kcalloc usage

adreno_show_object() is a trap!  It will re-allocate the pointer it is
passed on first call, when the data is ascii85 encoded, using kvmalloc/
kvfree().  Which means the data *passed* to it must be kvmalloc'd, ie.
we cannot use the state_kcalloc() helper.

This partially reverts commit ec8f181 ("drm/msm/a6xx: Replace
kcalloc() with kvzalloc()"), but adds the missing kvfree() to fix the
memory leak that was present previously.  And adds a warning comment.

Fixes: ec8f181 ("drm/msm/a6xx: Replace kcalloc() with kvzalloc()")
Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/20
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/507014/
Link: https://lore.kernel.org/r/20221013225520.371226-2-robdclark@gmail.com

drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c

@@ -819,7 +819,7 @@ static struct msm_gpu_state_bo *a6xx_snapshot_gmu_bo(
 
 	snapshot->iova = bo->iova;
 	snapshot->size = bo->size;
-	snapshot->data = state_kcalloc(a6xx_state, 1, snapshot->size);
+	snapshot->data = kvzalloc(snapshot->size, GFP_KERNEL);
 	if (!snapshot->data)
 		return NULL;
 
@@ -1034,6 +1034,15 @@ static void a6xx_gpu_state_destroy(struct kref *kref)
 	struct a6xx_gpu_state *a6xx_state = container_of(state,
 			struct a6xx_gpu_state, base);
 
+	if (a6xx_state->gmu_log)
+		kvfree(a6xx_state->gmu_log->data);
+
+	if (a6xx_state->gmu_hfi)
+		kvfree(a6xx_state->gmu_hfi->data);
+
+	if (a6xx_state->gmu_debug)
+		kvfree(a6xx_state->gmu_debug->data);
+
 	list_for_each_entry_safe(obj, tmp, &a6xx_state->objs, node)
 		kvfree(obj);
 

drivers/gpu/drm/msm/adreno/adreno_gpu.c

@@ -729,7 +729,12 @@ static char *adreno_gpu_ascii85_encode(u32 *src, size_t len)
 	return buf;
 }
 
-/* len is expected to be in bytes */
+/* len is expected to be in bytes
+ *
+ * WARNING: *ptr should be allocated with kvmalloc or friends.  It can be free'd
+ * with kvfree() and replaced with a newly kvmalloc'd buffer on the first call
+ * when the unencoded raw data is encoded
+ */
 void adreno_show_object(struct drm_printer *p, void **ptr, int len,
 		bool *encoded)
 {