linux-stable.git/drivers/video/fbdev, branch v5.15.211

fbdev: modedb: Fix misaligned fields in the 1920x1080-60 mode

2026-07-04T11:39:40+00:00

commit d894c48a57d78206e4df9c90d4acfaf39394806a upstream.

The 1920x1080@60 modedb entry has one too many initializers before
its sync field: a stray "0" occupies the sync slot, which shifts the
remaining values by one field. The entry therefore decodes as
sync = 0, vmode = FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT (0x3,
i.e. FB_VMODE_INTERLACED | FB_VMODE_DOUBLE), and flag =
FB_VMODE_NONINTERLACED, instead of the intended sync = positive H/V,
vmode = non-interlaced.

fb_find_mode() then returns a 1920x1080 mode flagged as interlaced +
doublescan with active-low syncs. Drivers that honour var->vmode and
var->sync when programming display timing enable doublescan and the
wrong sync polarity, corrupting the output.

Drop the stray initializer so sync and vmode hold their intended
values (positive H/V sync, non-interlaced), matching the adjacent
1920x1200 entry.

Fixes: c8902258b2b8 ("fbdev: modedb: Add 1920x1080 at 60 Hz video mode")
Cc: stable@vger.kernel.org
Signed-off-by: Steffen Persvold 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var

2026-07-04T11:39:40+00:00

commit 7f08fc10fa3d3366dc3af723970bd03d7d6d10e3 upstream.

info->var, a framebuffer's current mode, is expected to have a matching
entry in info->modelist. var_to_display() relies on this and treats a
failed fb_match_mode() as "This should not happen". fb_set_var() keeps it
true by adding the mode to the list on every change, and
do_register_framebuffer() does the same at registration.

store_modes() replaces the modelist from userspace. fb_new_modelist()
validates the new modes but does not check that info->var still has a
match. It relies on fbcon_new_modelist() to re-point consoles, but that
only handles consoles mapped to the framebuffer. With fbcon unbound there
are none, so info->var is left describing a mode that is no longer in the
list.

A later console takeover runs var_to_display(), where fb_match_mode()
returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it
to display_to_var(), and fb_videomode_to_var() dereferences the NULL mode.

Keep the current mode in the list in fb_new_modelist(), the same way
fb_set_var() does.

Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Ian Bridges 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbdev: vt8500lcdfb: Fix dma_free_coherent() cpu_addr parameter

2026-06-19T11:33:50+00:00

Before commit 63a11adaceb8 "fbdev/vt8500lcdfb: Initialize fb_ops with
fbdev macros", the virtual address of the screen buffer was stored in
the fb_info::screen_base field and not fb_info::screen_buffer.  The
backport of commit 88b3b9924337 ("fbdev: vt8500lcdfb: fix missing
dma_free_coherent()") did not take that into account.

Change the cpu_addr parameter to dma_free_coherent() accordingly.

Fixes: 9c3873cccb3f ("fbdev: vt8500lcdfb: fix missing dma_free_coherent()")
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

fbcon: Avoid OOB font access if console rotation fails

2026-06-19T11:33:44+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

2026-06-19T11:33:41+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(sizeof(*fbdefio_state), GFP_KERNEL)` ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

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

2026-06-01T15:35:40+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

2026-06-01T15:35:30+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

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

2026-06-01T15:35:19+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: efifb: Register sysfs groups through driver core

2026-06-01T15:35:11+00:00

[ Upstream commit 95cdd538e0e5677efbdf8aade04ec098ab98f457 ]

The driver core can register and cleanup sysfs groups already.
Make use of that functionality to simplify the error handling and
cleanup.

Also avoid a UAF race during unregistering where the sysctl attributes
were usable after the info struct was freed.

Signed-off-by: Thomas Weißschuh 
Signed-off-by: Helge Deller 
[ Minor context conflict resolved. ]
Signed-off-by: Alva Lan 
Signed-off-by: Greg Kroah-Hartman

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

2026-06-01T15:35:05+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