dmt_mode is allocated and never freed in this function. It was found with the ast driver, but most drivers using generic fbdev setup are probably affected.
This fixes the following kmemleak report: backtrace: [<00000000b391296d>] drm_mode_duplicate+0x45/0x220 [drm] [<00000000e45bb5b3>] drm_client_target_cloned.constprop.0+0x27b/0x480 [drm] [<00000000ed2d3a37>] drm_client_modeset_probe+0x6bd/0xf50 [drm] [<0000000010e5cc9d>] __drm_fb_helper_initial_config_and_unlock+0xb4/0x2c0 [drm_kms_helper] [<00000000909f82ca>] drm_fbdev_client_hotplug+0x2bc/0x4d0 [drm_kms_helper] [<00000000063a69aa>] drm_client_register+0x169/0x240 [drm] [<00000000a8c61525>] ast_pci_probe+0x142/0x190 [ast] [<00000000987f19bb>] local_pci_probe+0xdc/0x180 [<000000004fca231b>] work_for_cpu_fn+0x4e/0xa0 [<0000000000b85301>] process_one_work+0x8b7/0x1540 [<000000003375b17c>] worker_thread+0x70a/0xed0 [<00000000b0d43cd9>] kthread+0x29f/0x340 [<000000008d770833>] ret_from_fork+0x1f/0x30 unreferenced object 0xff11000333089a00 (size 128):
cc: stable@vger.kernel.org Fixes: 1d42bbc8f7f9 ("drm/fbdev: fix cloning on fbcon") Reported-by: Zhang Yi yizhan@redhat.com Signed-off-by: Jocelyn Falempe jfalempe@redhat.com Reviewed-by: Javier Martinez Canillas javierm@redhat.com Reviewed-by: Thomas Zimmermann tzimmermann@suse.de Link: https://patchwork.freedesktop.org/patch/msgid/20230711092203.68157-2-jfalemp... (cherry picked from commit c2a88e8bdf5f6239948d75283d0ae7e0c7945b03) Signed-off-by: Jocelyn Falempe jfalempe@redhat.com --- drivers/gpu/drm/drm_fb_helper.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index fbf7f28d9df9..e8d0dbe92048 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -2112,6 +2112,9 @@ static bool drm_target_cloned(struct drm_fb_helper *fb_helper, can_clone = true; dmt_mode = drm_mode_find_dmt(fb_helper->dev, 1024, 768, 60, false);
+ if (!dmt_mode) + goto fail; + drm_fb_helper_for_each_connector(fb_helper, i) { if (!enabled[i]) continue; @@ -2124,11 +2127,13 @@ static bool drm_target_cloned(struct drm_fb_helper *fb_helper, if (!modes[i]) can_clone = false; } + kfree(dmt_mode);
if (can_clone) { DRM_DEBUG_KMS("can clone using 1024x768\n"); return true; } +fail: DRM_INFO("kms: can't enable cloning when we probably wanted to.\n"); return false; }