linux-kernel - [PATCH 3/3] drm/radeon: Remove calls to drm_put

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Message-ID: <20251018054451.259432-4-daniel@0x0f.com>
Date: Sat, 18 Oct 2025 14:44:51 +0900
From: Daniel Palmer <daniel@...f.com>
To: alexander.deucher@....com,
	christian.koenig@....com,
	airlied@...il.com,
	simona@...ll.ch,
	wuhoipok@...il.com
Cc: amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	Daniel Palmer <daniel@...f.com>
Subject: [PATCH 3/3] drm/radeon: Remove calls to drm_put_dev()

Since the allocation of the drivers main structure was changed to
devm_drm_dev_alloc() drm_put_dev()'ing to trigger it to be free'd
should be done by devres.

However, drm_put_dev() is still in the probe error and device remove
paths. When the driver fails to probe warnings like the following are
shown because devres is trying to drm_put_dev() after the driver
already did it.

[    5.642230] radeon 0000:01:05.0: probe with driver radeon failed with error -22
[    5.649605] ------------[ cut here ]------------
[    5.649607] refcount_t: underflow; use-after-free.
[    5.649620] WARNING: CPU: 0 PID: 357 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110

Fixes: a9ed2f052c5c ("drm/radeon: change drm_dev_alloc to devm_drm_dev_alloc")
Signed-off-by: Daniel Palmer <daniel@...f.com>
---
 drivers/gpu/drm/radeon/radeon_drv.c | 25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index eb5138da8d5b..350f88af888d 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -315,17 +315,17 @@ static int radeon_pci_probe(struct pci_dev *pdev,
 
 	ret = pci_enable_device(pdev);
 	if (ret)
-		goto err_free;
+		return ret;
 
 	pci_set_drvdata(pdev, ddev);
 
 	ret = radeon_driver_load_kms(ddev, flags);
 	if (ret)
-		goto err_agp;
+		goto err;
 
 	ret = drm_dev_register(ddev, flags);
 	if (ret)
-		goto err_agp;
+		goto err;
 
 	if (rdev->mc.real_vram_size <= (8 * 1024 * 1024))
 		format = drm_format_info(DRM_FORMAT_C8);
@@ -338,30 +338,14 @@ static int radeon_pci_probe(struct pci_dev *pdev,
 
 	return 0;
 
-err_agp:
+err:
 	pci_disable_device(pdev);
-err_free:
-	drm_dev_put(ddev);
 	return ret;
 }
 
-static void
-radeon_pci_remove(struct pci_dev *pdev)
-{
-	struct drm_device *dev = pci_get_drvdata(pdev);
-
-	drm_put_dev(dev);
-}
-
 static void
 radeon_pci_shutdown(struct pci_dev *pdev)
 {
-	/* if we are running in a VM, make sure the device
-	 * torn down properly on reboot/shutdown
-	 */
-	if (radeon_device_is_virtual())
-		radeon_pci_remove(pdev);
-
 #if defined(CONFIG_PPC64) || defined(CONFIG_MACH_LOONGSON64)
 	/*
 	 * Some adapters need to be suspended before a
@@ -614,7 +598,6 @@ static struct pci_driver radeon_kms_pci_driver = {
 	.name = DRIVER_NAME,
 	.id_table = pciidlist,
 	.probe = radeon_pci_probe,
-	.remove = radeon_pci_remove,
 	.shutdown = radeon_pci_shutdown,
 	.driver.pm = &radeon_pm_ops,
 };
-- 
2.51.0