drm/i915/panic: fix panic structure allocation memory leak

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
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20251015095135.2183415-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
index 9c256a2805e402b5daeba6f7231fa8e6b4f67121..3958628c73e978c7a4b4d3a22f7bc5c19db52fa5 100644 (file)
--- 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 @@ err_bo_framebuffer_fini:
        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;
 }