FAILED: patch "[PATCH] drm/client: Fix memory leak in drm_client_target_cloned" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x c2a88e8bdf5f6239948d75283d0ae7e0c7945b03
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023072326-snuff-obnoxious-af01@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

c2a88e8bdf5f ("drm/client: Fix memory leak in drm_client_target_cloned") cf13909aee05 ("drm/fb-helper: Move out modeset config code") aafa9e066872 ("drm/fb-helper: Prepare to move out modeset config code") e5852bee90d6 ("drm/fb-helper: Remove drm_fb_helper_connector") aec3925f093d ("drm/fb-helper: Move out commit code")
eade2a17ddc5 ("drm/fb-helper: Prepare to move out commit code") d81294afeecd ("drm/fb-helper: Remove drm_fb_helper_crtc") 4672b1d65fc9 ("Merge remote-tracking branch 'drm/drm-next' into drm-misc-next")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c2a88e8bdf5f6239948d75283d0ae7e0c7945b03 Mon Sep 17 00:00:00 2001
From: Jocelyn Falempe <[email protected]>
Date: Tue, 11 Jul 2023 11:20:43 +0200
Subject: [PATCH] drm/client: Fix memory leak in drm_client_target_cloned

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):

index 1b12a3c201a3..a4a62aa99984 100644
@@ -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;
 }

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):

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

index fbe9156c9e7c..ee6801fa36ad 100644
@@ -2233,6 +2233,9 @@ 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;

@@ -2249,11 +2252,13 @@ 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;
 }

2.41.0

Both now queued up, thanks.

greg k-h