linux-stable.git/drivers/video/fbdev, branch v6.6.141

fbdev: offb: fix PCI device reference leak on probe failure

2026-05-23T11:03:26+00:00

[ Upstream commit 869b93ba04088713596e68453c1146f52f713290 ]

offb_init_nodriver() gets a referenced PCI device with pci_get_device().
If pci_enable_device() fails, the function returns without dropping that
reference.

Release the PCI device reference before returning from the
pci_enable_device() failure path.

Fixes: 5bda8f7b5468 ("video: fbdev: offb: Call pci_enable_device() before using the PCI VGA device")
Co-developed-by: Myeonghun Pak 
Signed-off-by: Myeonghun Pak 
Co-developed-by: Ijae Kim 
Signed-off-by: Ijae Kim 
Co-developed-by: Taegyu Kim 
Signed-off-by: Taegyu Kim 
Signed-off-by: Yuho Choi 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: matroxfb: Mark variable with __maybe_unused to avoid W=1 build break

2026-05-23T11:03:11+00:00

[ Upstream commit caf6144053b4e1c815aa56afb54745a176f999df ]

Clang is not happy about set but unused variable:

drivers/video/fbdev/matrox/g450_pll.c:412:18: error: variable 'mnp' set but not used
412 | unsigned int mnp;
| ^
1 error generated.

Since the commit 7b987887f97b ("video: fbdev: matroxfb: remove dead code
and set but not used variable") the 'mnp' became unused, but eliminating
that code might have side-effects. The question here is what should we do
with 'mnp'? The easiest way out is just mark it with __maybe_unused which
will shut the compiler up and won't change any possible IO flow. So does
this change.

A dive into the history of the driver:

The problem was revealed when the #if 0 guarded code along with unused
pixel_vco variable was removed. That code was introduced in the original
commit 213d22146d1f ("[PATCH] (1/3) matroxfb for 2.5.3"). And then guarded
in the commit 705e41f82988 ("matroxfb DVI updates: Handle DVI output on
G450/G550. Powerdown unused portions of G450/G550 DAC. Split G450/G550 DAC
from older DAC1064 handling. Modify PLL setting when both CRTCs use same
pixel clocks.").

NOTE: The two commits mentioned above pre-date Git era and available in
history.git repository for archaeological purposes.

Even without that guard the modern compilers may see that the pixel_vco
wasn't ever used and seems a leftover after some debug or review made
25 years ago.

The g450_mnp2vco() doesn't have any IO and as Jason said doesn't seem
to have any side effects either than some unneeded CPU processing during
runtime. I agree that's unlikely that timeout (or heating up the CPU) has
any effect on the HW (GPU/display) functionality.

Fixes: 7b987887f97b ("video: fbdev: matroxfb: remove dead code and set but not used variable")
Signed-off-by: Andy Shevchenko
Reviewed-by: Jason Yan
Signed-off-by: Helge Deller
Signed-off-by: Sasha Levin

fbcon: Avoid OOB font access if console rotation fails

2026-05-17T15:13:52+00:00

[ Upstream commit e4ef723d8975a2694cc90733a6b888a5e2841842 ]

Clear the font buffer if the reallocation during console rotation fails
in fbcon_rotate_font(). The putcs implementations for the rotated buffer
will return early in this case. See [1] for an example.

Currently, fbcon_rotate_font() keeps the old buffer, which is too small
for the rotated font. Printing to the rotated console with a high-enough
character code will overflow the font buffer.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann 
Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap")
Cc: stable@vger.kernel.org # v2.6.15+
Link: https://elixir.bootlin.com/linux/v6.19/source/drivers/video/fbdev/core/fbcon_ccw.c#L144 # [1]
Signed-off-by: Helge Deller 
[ renamed `par` to `ops` to match the 6.12 local pointer name ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

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

2026-05-17T15:13:49+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` with `kzalloc`, and dropped `mutex_destroy(&fbdefio->lock)` ]
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

2026-05-17T15:13:34+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

2026-04-27T13:23:31+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

2026-04-27T13:23:30+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

2026-03-04T12:21:19+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

2026-03-04T12:21:19+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()

2026-03-04T12:21:18+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