[PATCH v2] drm/i915/panic: fix panic structure allocation memory leak

[Jani Nikula <jani.nikula@intel.com>]

Separating the panic allocation from framebuffer allocation in commit
729c5f7ffa83 ("drm/{i915,xe}/panic: move framebuffer allocation where it
belongs") failed to deallocate the panic structure anywhere.

The fix is two-fold. First, free the panic structure in
intel_user_framebuffer_destroy() in the general case. Second, move the
panic allocation later to intel_framebuffer_init() to not leak the panic
structure in error paths (if any, now or later) between
intel_framebuffer_alloc() and intel_framebuffer_init().

v2: Rebase

Fixes: 729c5f7ffa83 ("drm/{i915,xe}/panic: move framebuffer allocation where it belongs")
Cc: Jocelyn Falempe <jfalempe@redhat.com>
Cc: Maarten Lankhorst <dev@lankhorst.se>
Reported-by: Michał Grzelak <michal.grzelak@intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Michał Grzelak <michal.grzelak@intel.com> # v1
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/display/intel_fb.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
index 9c256a2805e4..3958628c73e9 100644
--- a/drivers/gpu/drm/i915/display/intel_fb.c
+++ b/drivers/gpu/drm/i915/display/intel_fb.c
@@ -2114,6 +2114,7 @@ static void intel_user_framebuffer_destroy(struct drm_framebuffer *fb)
 
 	intel_frontbuffer_put(intel_fb->frontbuffer);
 
+	kfree(intel_fb->panic);
 	kfree(intel_fb);
 }
 
@@ -2212,16 +2213,22 @@ int intel_framebuffer_init(struct intel_framebuffer *intel_fb,
 	struct intel_display *display = to_intel_display(obj->dev);
 	struct drm_framebuffer *fb = &intel_fb->base;
 	u32 max_stride;
-	int ret = -EINVAL;
+	int ret;
 	int i;
 
+	intel_fb->panic = intel_panic_alloc();
+	if (!intel_fb->panic)
+		return -ENOMEM;
+
 	/*
 	 * intel_frontbuffer_get() must be done before
 	 * intel_fb_bo_framebuffer_init() to avoid set_tiling vs. addfb race.
 	 */
 	intel_fb->frontbuffer = intel_frontbuffer_get(obj);
-	if (!intel_fb->frontbuffer)
-		return -ENOMEM;
+	if (!intel_fb->frontbuffer) {
+		ret = -ENOMEM;
+		goto err_free_panic;
+	}
 
 	ret = intel_fb_bo_framebuffer_init(obj, mode_cmd);
 	if (ret)
@@ -2320,6 +2327,9 @@ int intel_framebuffer_init(struct intel_framebuffer *intel_fb,
 	intel_fb_bo_framebuffer_fini(obj);
 err_frontbuffer_put:
 	intel_frontbuffer_put(intel_fb->frontbuffer);
+err_free_panic:
+	kfree(intel_fb->panic);
+
 	return ret;
 }
 
@@ -2346,20 +2356,11 @@ intel_user_framebuffer_create(struct drm_device *dev,
 struct intel_framebuffer *intel_framebuffer_alloc(void)
 {
 	struct intel_framebuffer *intel_fb;
-	struct intel_panic *panic;
 
 	intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL);
 	if (!intel_fb)
 		return NULL;
 
-	panic = intel_panic_alloc();
-	if (!panic) {
-		kfree(intel_fb);
-		return NULL;
-	}
-
-	intel_fb->panic = panic;
-
 	return intel_fb;
 }
 
-- 
2.47.3