From c2a88e8bdf5f6239948d75283d0ae7e0c7945b03 Mon Sep 17 00:00:00 2001
From: Jocelyn Falempe <jfalempe@redhat.com>
Date: Tue, 11 Jul 2023 11:20:43 +0200
Subject: [PATCH] drm/client: Fix memory leak in drm_client_target_cloned
Git-commit: c2a88e8bdf5f6239948d75283d0ae7e0c7945b03
Patch-mainline: v6.5-rc3
References: git-fixes

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-jfalempe@redhat.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/drm_client_modeset.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index 1b12a3c201a3..a4a62aa99984 100644
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -311,6 +311,9 @@ static bool drm_client_target_cloned(struct drm_device *dev,
 	can_clone = true;
 	dmt_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
 
+	if (!dmt_mode)
+		goto fail;
+
 	for (i = 0; i < connector_count; i++) {
 		if (!enabled[i])
 			continue;
@@ -326,11 +329,13 @@ static bool drm_client_target_cloned(struct drm_device *dev,
 		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;
 }
-- 
2.35.3