linux-kernel - [PATCH 1/1] drm/hyperv: Fix address space leak when Hyper-V DRM device is removed

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Message-Id: <20250210193441.2414-1-mhklinux@outlook.com>
Date: Mon, 10 Feb 2025 11:34:41 -0800
From: mhkelley58@...il.com
To: drawat.floss@...il.com,
	maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	christophe.jaillet@...adoo.fr,
	ssengar@...ux.microsoft.com,
	wei.liu@...nel.org
Cc: dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	linux-hyperv@...r.kernel.org
Subject: [PATCH 1/1] drm/hyperv: Fix address space leak when Hyper-V DRM device is removed

From: Michael Kelley <mhklinux@...look.com>

When a Hyper-V DRM device is probed, the driver allocates MMIO space for
the vram, and maps it cacheable. If the device removed, or in the error
path for device probing, the MMIO space is released but no unmap is done.
Consequently the kernel address space for the mapping is leaked.

Fix this by adding iounmap() calls in the device removal path, and in the
error path during device probing.

Fixes: f1f63cbb705d ("drm/hyperv: Fix an error handling path in hyperv_vmbus_probe()")
Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
Signed-off-by: Michael Kelley <mhklinux@...look.com>
---
 drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
index e0953777a206..b491827941f1 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
@@ -156,6 +156,7 @@ static int hyperv_vmbus_probe(struct hv_device *hdev,
 	return 0;
 
 err_free_mmio:
+	iounmap(hv->vram);
 	vmbus_free_mmio(hv->mem->start, hv->fb_size);
 err_vmbus_close:
 	vmbus_close(hdev->channel);
@@ -174,6 +175,7 @@ static void hyperv_vmbus_remove(struct hv_device *hdev)
 	vmbus_close(hdev->channel);
 	hv_set_drvdata(hdev, NULL);
 
+	iounmap(hv->vram);
 	vmbus_free_mmio(hv->mem->start, hv->fb_size);
 }
 
-- 
2.25.1