linux-stable.git/drivers/video/fbdev, branch v6.18.30

fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info

2026-05-14T13:30:25+00:00

[ Upstream commit 9ded47ad003f09a94b6a710b5c47f4aa5ceb7429 ]

Hold state of deferred I/O in struct fb_deferred_io_state. Allocate an
instance as part of initializing deferred I/O and remove it only after
the final mapping has been closed. If the fb_info and the contained
deferred I/O meanwhile goes away, clear struct fb_deferred_io_state.info
to invalidate the mapping. Any access will then result in a SIGBUS
signal.

Fixes a long-standing problem, where a device hot-unplug happens while
user space still has an active mapping of the graphics memory. The hot-
unplug frees the instance of struct fb_info. Accessing the memory will
operate on undefined state.

Signed-off-by: Thomas Zimmermann 
Fixes: 60b59beafba8 ("fbdev: mm: Deferred IO support")
Cc: Helge Deller 
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # v2.6.22+
Signed-off-by: Helge Deller 
[ replaced kzalloc_obj(*fbdefio_state) with kzalloc(sizeof(*fbdefio_state), GFP_KERNEL) ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free

2026-05-14T13:30:10+00:00

commit 8de779dc40d35d39fa07387b6f921eb11df0f511 upstream.

dlfb_ops_mmap() uses remap_pfn_range() to map vmalloc framebuffer pages
to userspace but sets no vm_ops on the VMA. This means the kernel cannot
track active mmaps. When dlfb_realloc_framebuffer() replaces the backing
buffer via FBIOPUT_VSCREENINFO, existing mmap PTEs are not invalidated.
On USB disconnect, dlfb_ops_destroy() calls vfree() on the old pages
while userspace PTEs still reference them, resulting in a use-after-free:
the process retains read/write access to freed kernel pages.

Add vm_operations_struct with open/close callbacks that maintain an
atomic mmap_count on struct dlfb_data. In dlfb_realloc_framebuffer(),
check mmap_count and return -EBUSY if the buffer is currently mapped,
preventing buffer replacement while userspace holds stale PTEs.

Tested with PoC using dummy_hcd + raw_gadget USB device emulation.

Signed-off-by: Rajat Gupta 
Acked-by: Greg Kroah-Hartman 
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbdev: udlfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

2026-04-22T11:22:28+00:00

commit a31e4518bec70333a0a98f2946a12b53b45fe5b9 upstream.

Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide
by zero error"), we also need to prevent that same crash from happening
in the udlfb driver as it uses pixclock directly when dividing, which
will crash.

Cc: Bernie Thompson 
Cc: Helge Deller 
Fixes: 59277b679f8b ("Staging: udlfb: add dynamic modeset support")
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbdev: tdfxfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

2026-04-22T11:22:26+00:00

commit 8f98b81fe011e1879e6a7b1247e69e06a5e17af2 upstream.

Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide
by zero error"), we also need to prevent that same crash from happening
in the udlfb driver as it uses pixclock directly when dividing, which
will crash.

Cc: Helge Deller 
Assisted-by: gregkh_clanker_t1000
Cc: stable 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbcon: Remove struct fbcon_display.inverse

2026-03-04T12:21:32+00:00

[ Upstream commit 30baedeeeab524172abc0b58cb101e8df86b5be8 ]

The field inverse in struct fbcon_display is unused. Remove it.

Signed-off-by: Thomas Zimmermann 
Cc:  # v6.0+
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: ffb: fix corrupted video output on Sun FFB1

2026-03-04T12:21:31+00:00

[ Upstream commit b28da0d092461ac239ff034a8ac3129320177ba3 ]

Fix Sun FFB1 corrupted video out ([1] and [2]) by disabling overlay and
initializing window mode to a known state. The issue never appeared on
my FFB2+/vertical nor Elite3D/M6. It could also depend on the PROM
version.

/SUNW,ffb@1e,0: FFB at 000001fc00000000, type 11, DAC pnum[236c] rev[10] manuf_rev[4]
X (II) /dev/fb0: Detected FFB1, Z-buffer, Single-buffered.
X (II) /dev/fb0: BT9068 (PAC1) ramdac detected (with normal cursor control)
X (II) /dev/fb0: Detected Creator/Creator3D

[1] https://www.instagram.com/p/DUTcSmSjSem/
[2] https://chaos.social/@ReneRebe/116023241660154102

Signed-off-by: René Rebe 
Cc: stable@kernel.org
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: vt8500lcdfb: fix missing dma_free_coherent()

2026-03-04T12:21:31+00:00

[ Upstream commit 88b3b9924337336a31cefbe99a22ed09401be74a ]

fbi->fb.screen_buffer is allocated with dma_alloc_coherent() but is not
freed if the error path is reached.

Fixes: e7b995371fe1 ("video: vt8500: Add devicetree support for vt8500-fb and wm8505-fb")
Cc: 
Signed-off-by: Thomas Fourier 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbcon: check return value of con2fb_acquire_newinfo()

2026-03-04T12:21:31+00:00

[ Upstream commit 011a0502801c8536f64141a2b61362c14f456544 ]

If fbcon_open() fails when called from con2fb_acquire_newinfo() then
info->fbcon_par pointer remains NULL which is later dereferenced.

Add check for return value of the function con2fb_acquire_newinfo() to
avoid it.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: d1baa4ffa677 ("fbcon: set_con2fb_map fixes")
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Vatoropin 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: Use device_create_with_groups() to fix sysfs groups registration race

2026-03-04T12:21:31+00:00

[ Upstream commit 68eeb0871e986ae5462439dae881e3a27bcef85f ]

The fbdev sysfs attributes are registered after sending the uevent for
the device creation, leaving a race window where e.g. udev rules may
not be able to access the sysfs attributes because the registration is
not done yet.

Fix this by switching to device_create_with_groups(). This also results in
a nice cleanup. After switching to device_create_with_groups() all that
is left of fb_init_device() is setting the drvdata and that can be passed
to device_create[_with_groups]() too. After which fb_init_device() can
be completely removed.

Dropping fb_init_device() + fb_cleanup_device() in turn allows removing
fb_info.class_flag as they were the only user of this field.

Fixes: 5fc830d6aca1 ("fbdev: Register sysfs groups through device_add_group")
Cc: stable@vger.kernel.org
Cc: Shixiong Ou 
Signed-off-by: Hans de Goede 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: au1200fb: Fix a memory leak in au1200fb_drv_probe()

2026-02-26T22:59:28+00:00

[ Upstream commit ce4e25198a6aaaaf36248edf8daf3d744ec8e309 ]

In au1200fb_drv_probe(), when platform_get_irq fails(), it directly
returns from the function with an error code, which causes a memory
leak.

Replace it with a goto label to ensure proper cleanup.

Fixes: 4e88761f5f8c ("fbdev: au1200fb: Fix missing IRQ check in au1200fb_drv_probe")
Signed-off-by: Felix Gu 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin