video/aperture: optionally match the device in sysfb_disable()

In aperture_remove_conflicting_pci_devices(), we currently only
call sysfb_disable() on vga class devices.  This leads to the
following problem when the pimary device is not VGA compatible:

1. A PCI device with a non-VGA class is the boot display
2. That device is probed first and it is not a VGA device so
   sysfb_disable() is not called, but the device resources
   are freed by aperture_detach_platform_device()
3. Non-primary GPU has a VGA class and it ends up calling sysfb_disable()
4. NULL pointer dereference via sysfb_disable() since the resources
   have already been freed by aperture_detach_platform_device() when
   it was called by the other device.

Fix this by passing a device pointer to sysfb_disable() and checking
the device to determine if we should execute it or not.

v2: Fix build when CONFIG_SCREEN_INFO is not set
v3: Move device check into the mutex
    Drop primary variable in aperture_remove_conflicting_pci_devices()
    Drop __init on pci sysfb_pci_dev_is_enabled()

Fixes: 5ae3716cfdcd ("video/aperture: Only remove sysfb on the default vga pci device")
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Helge Deller <deller@gmx.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240821191135.829765-1-alexander.deucher@amd.com

1 files changed, 3 insertions, 8 deletions

diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
index 561be8feca96..2b5a1e666e9b 100644
--- a/drivers/video/aperture.c
+++ b/drivers/video/aperture.c
@@ -293,7 +293,7 @@ int aperture_remove_conflicting_devices(resource_size_t base, resource_size_t si
 	 * ask for this, so let's assume that a real driver for the display
 	 * was already probed and prevent sysfb to register devices later.
 	 */
-	sysfb_disable();
+	sysfb_disable(NULL);
 
 	aperture_detach_devices(base, size);
 
@@ -346,15 +346,10 @@ EXPORT_SYMBOL(__aperture_remove_legacy_vga_devices);
  */
 int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *name)
 {
-	bool primary = false;
 	resource_size_t base, size;
 	int bar, ret = 0;
 
-	if (pdev == vga_default_device())
-		primary = true;
-
-	if (primary)
-		sysfb_disable();
+	sysfb_disable(&pdev->dev);
 
 	for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) {
 		if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
@@ -370,7 +365,7 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na
 	 * that consumes the VGA framebuffer I/O range. Remove this
 	 * device as well.
 	 */
-	if (primary)
+	if (pdev == vga_default_device())
 		ret = __aperture_remove_legacy_vga_devices(pdev);
 
 	return ret;