The patch below does not apply to the 6.1-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 stable@vger.kernel.org.

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-6.1.y git checkout FETCH_HEAD git cherry-pick -x b49420d6a1aeb399e5b107fc6eb8584d0860fbd7 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024083019-grumble-fading-91fb@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

b49420d6a1ae ("video/aperture: optionally match the device in sysfb_disable()") 4e754597d603 ("firmware/sysfb: Create firmware device only for enabled PCI devices") 9eac534db001 ("firmware/sysfb: Set firmware-framebuffer parent device") 2bebc3cd4870 ("Revert "firmware/sysfb: Clear screen_info state after consuming it"") 38814330fedd ("Merge tag 'devicetree-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux")

thanks,

greg k-h

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

From b49420d6a1aeb399e5b107fc6eb8584d0860fbd7 Mon Sep 17 00:00:00 2001 From: Alex Deucher alexander.deucher@amd.com Date: Wed, 21 Aug 2024 15:11:35 -0400 Subject: [PATCH] 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-alexan...

diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c index 921f61507ae8..02a07d3d0d40 100644 --- a/drivers/firmware/sysfb.c +++ b/drivers/firmware/sysfb.c @@ -39,6 +39,8 @@ static struct platform_device *pd; static DEFINE_MUTEX(disable_lock); static bool disabled;

+static struct device *sysfb_parent_dev(const struct screen_info *si); + static bool sysfb_unregister(void) { if (IS_ERR_OR_NULL(pd)) @@ -52,6 +54,7 @@ static bool sysfb_unregister(void)

/** * sysfb_disable() - disable the Generic System Framebuffers support + * @dev: the device to check if non-NULL * * This disables the registration of system framebuffer devices that match the * generic drivers that make use of the system framebuffer set up by firmware. @@ -61,17 +64,21 @@ static bool sysfb_unregister(void) * Context: The function can sleep. A @disable_lock mutex is acquired to serialize * against sysfb_init(), that registers a system framebuffer device. */ -void sysfb_disable(void) +void sysfb_disable(struct device *dev) { + struct screen_info *si = &screen_info; + mutex_lock(&disable_lock); - sysfb_unregister(); - disabled = true; + if (!dev || dev == sysfb_parent_dev(si)) { + sysfb_unregister(); + disabled = true; + } mutex_unlock(&disable_lock); } EXPORT_SYMBOL_GPL(sysfb_disable);

#if defined(CONFIG_PCI) -static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) +static bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) { /* * TODO: Try to integrate this code into the PCI subsystem @@ -87,13 +94,13 @@ static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) return true; } #else -static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) +static bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) { return false; } #endif

-static __init struct device *sysfb_parent_dev(const struct screen_info *si) +static struct device *sysfb_parent_dev(const struct screen_info *si) { struct pci_dev *pdev;

diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 389d4ea6bfc1..ef622d41eb5b 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -592,7 +592,7 @@ static int __init of_platform_default_populate_init(void) * This can happen for example on DT systems that do EFI * booting and may provide a GOP handle to the EFI stub. */ - sysfb_disable(); + sysfb_disable(NULL); of_platform_device_create(node, NULL, NULL); of_node_put(node); } 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; diff --git a/include/linux/sysfb.h b/include/linux/sysfb.h index c9cb657dad08..bef5f06a91de 100644 --- a/include/linux/sysfb.h +++ b/include/linux/sysfb.h @@ -58,11 +58,11 @@ struct efifb_dmi_info {

#ifdef CONFIG_SYSFB

-void sysfb_disable(void); +void sysfb_disable(struct device *dev);

#else /* CONFIG_SYSFB */

-static inline void sysfb_disable(void) +static inline void sysfb_disable(struct device *dev) { }