Commit Graph

2928 Commits

Author SHA1 Message Date
Thomas Zimmermann 2b53d3a52e fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info
[ Upstream commit 9ded47ad00 ]

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 <tzimmermann@suse.de>
Fixes: 60b59beafb ("fbdev: mm: Deferred IO support")
Cc: Helge Deller <deller@gmx.de>
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 <deller@gmx.de>
[ replaced `kzalloc_obj()` with `kzalloc(sizeof(*fbdefio_state), GFP_KERNEL)` ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-05-14 15:29:28 +02:00
Rajat Gupta 18dd358de7 fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free
commit 8de779dc40 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 <rajgupt@qti.qualcomm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-05-14 15:29:17 +02:00
Greg Kroah-Hartman 03797cdee3 fbdev: udlfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO
commit a31e4518be upstream.

Much like commit 19f953e743 ("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 <bernie@plugable.com>
Cc: Helge Deller <deller@gmx.de>
Fixes: 59277b679f ("Staging: udlfb: add dynamic modeset support")
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-22 13:18:59 +02:00
Greg Kroah-Hartman 53cb4e79a0 fbdev: tdfxfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO
commit 8f98b81fe0 upstream.

Much like commit 19f953e743 ("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 <deller@gmx.de>
Assisted-by: gregkh_clanker_t1000
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-22 13:18:57 +02:00
Thomas Zimmermann f73b3653a4 fbcon: Remove struct fbcon_display.inverse
[ Upstream commit 30baedeeea ]

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

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: <stable@vger.kernel.org> # v6.0+
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:58 -05:00
René Rebe 8225baf882 fbdev: ffb: fix corrupted video output on Sun FFB1
[ Upstream commit b28da0d092 ]

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 <rene@exactco.de>
Cc: stable@kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:58 -05:00
Thomas Fourier f47d5b9e8a fbdev: vt8500lcdfb: fix missing dma_free_coherent()
[ Upstream commit 88b3b99243 ]

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

Fixes: e7b995371f ("video: vt8500: Add devicetree support for vt8500-fb and wm8505-fb")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:57 -05:00
Andrey Vatoropin 0b038c0be6 fbcon: check return value of con2fb_acquire_newinfo()
[ Upstream commit 011a050280 ]

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: d1baa4ffa6 ("fbcon: set_con2fb_map fixes")
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Vatoropin <a.vatoropin@crpt.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:57 -05:00
Felix Gu 762a268189 fbdev: au1200fb: Fix a memory leak in au1200fb_drv_probe()
[ Upstream commit ce4e25198a ]

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: 4e88761f5f ("fbdev: au1200fb: Fix missing IRQ check in au1200fb_drv_probe")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:20:25 -05:00
Greg Kroah-Hartman 52917e265a fbdev: smscufx: properly copy ioctl memory to kernelspace
commit 120adae7b4 upstream.

The UFX_IOCTL_REPORT_DAMAGE ioctl does not properly copy data from
userspace to kernelspace, and instead directly references the memory,
which can cause problems if invalid data is passed from userspace.  Fix
this all up by correctly copying the memory before accessing it within
the kernel.

Reported-by: Tianchu Chen <flynnnchen@tencent.com>
Cc: stable <stable@kernel.org>
Cc: Steve Glendinning <steve.glendinning@shawell.net>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-02-19 16:29:55 +01:00
Guangshuo Li 9efa0dc462 fbdev: rivafb: fix divide error in nv3_arb()
commit 0209e21e3c upstream.

A userspace program can trigger the RIVA NV3 arbitration code by calling
the FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver
recomputes FIFO arbitration parameters in nv3_arb(), using state->mclk_khz
(derived from the PRAMDAC MCLK PLL) as a divisor without validating it
first.

In a normal setup, state->mclk_khz is provided by the real hardware and is
non-zero. However, an attacker can construct a malicious or misconfigured
device (e.g. a crafted/emulated PCI device) that exposes a bogus PLL
configuration, causing state->mclk_khz to become zero.  Once
nv3_get_param() calls nv3_arb(), the division by state->mclk_khz in the gns
calculation causes a divide error and crashes the kernel.

Fix this by checking whether state->mclk_khz is zero and bailing out before
doing the division.

The following log reveals it:

rivafb: setting virtual Y resolution to 2184
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 PID: 2187 Comm: syz-executor.0 Not tainted 5.18.0-rc1+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:nv3_arb drivers/video/fbdev/riva/riva_hw.c:439 [inline]
RIP: 0010:nv3_get_param+0x3ab/0x13b0 drivers/video/fbdev/riva/riva_hw.c:546
Call Trace:
  nv3CalcArbitration.constprop.0+0x255/0x460 drivers/video/fbdev/riva/riva_hw.c:603
  nv3UpdateArbitrationSettings drivers/video/fbdev/riva/riva_hw.c:637 [inline]
  CalcStateExt+0x447/0x1b90 drivers/video/fbdev/riva/riva_hw.c:1246
  riva_load_video_mode+0x8a9/0xea0 drivers/video/fbdev/riva/fbdev.c:779
  rivafb_set_par+0xc0/0x5f0 drivers/video/fbdev/riva/fbdev.c:1196
  fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1033
  do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1109
  fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1188
  __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:856

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-02-19 16:29:55 +01:00
René Rebe a135dfe84a fbdev: tcx.c fix mem_map to correct smem_start offset
commit 35fa2b4bf9 upstream.

403ae52ac0 ("sparc: fix drivers/video/tcx.c warning") changed the
physbase initializing breaking the user-space mmap, e.g. for Xorg
entirely.

Fix fbdev mmap table so the sbus mmap helper work correctly, and
not try to map vastly (physbase) offset memory.

Fixes: 403ae52ac0 ("sparc: fix drivers/video/tcx.c warning")
Cc: <stable@vger.kernel.org>
Signed-off-by: René Rebe <rene@exactco.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-08 10:14:45 +01:00
Thorsten Blum b58f85225b fbdev: pxafb: Fix multiple clamped values in pxafb_adjust_timing
commit 0155e868cb upstream.

The variables were never clamped because the return value of clamp_val()
was not used. Fix this by assigning the clamped values, and use clamp()
instead of clamp_val().

Cc: stable@vger.kernel.org
Fixes: 3f16ff608a ("[ARM] pxafb: cleanup of the timing checking code")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-08 10:14:44 +01:00
Rene Rebe 77c8170a62 fbdev: gbefb: fix to use physical address instead of dma address
commit e3f44742bb upstream.

While debuggigng why X would not start on mips64 Sgi/O2 I found the
phys adress being off. Turns out the gbefb passed the internal
dma_addr as phys. May be broken pre git history. Fix by converting
dma_to_phys.

Signed-off-by: René Rebe <rene@exactco.de>
Cc: <stable@vger.kernel.org> # v4.0+
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-08 10:14:44 +01:00
Abdun Nihaal d4b20e53b6 fbdev: ssd1307fb: fix potential page leak in ssd1307fb_probe()
[ Upstream commit 164312662a ]

The page allocated for vmem using __get_free_pages() is not freed on the
error paths after it. Fix that by adding a corresponding __free_pages()
call to the error path.

Fixes: facd94bc45 ("fbdev: ssd1307fb: Allocate page aligned video memory.")
Signed-off-by: Abdun Nihaal <nihaal@cse.iitm.ac.in>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-18 13:55:15 +01:00
Thomas Zimmermann 482330f826 drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup
[ Upstream commit eb76d0f555 ]

Protect vga_switcheroo_client_fb_set() with console lock. Avoids OOB
access in fbcon_remap_all(). Without holding the console lock the call
races with switching outputs.

VGA switcheroo calls fbcon_remap_all() when switching clients. The fbcon
function uses struct fb_info.node, which is set by register_framebuffer().
As the fb-helper code currently sets up VGA switcheroo before registering
the framebuffer, the value of node is -1 and therefore not a legal value.
For example, fbcon uses the value within set_con2fb_map() [1] as an index
into an array.

Moving vga_switcheroo_client_fb_set() after register_framebuffer() can
result in VGA switching that does not switch fbcon correctly.

Therefore move vga_switcheroo_client_fb_set() under fbcon_fb_registered(),
which already holds the console lock. Fbdev calls fbcon_fb_registered()
from within register_framebuffer(). Serializes the helper with VGA
switcheroo's call to fbcon_remap_all().

Although vga_switcheroo_client_fb_set() takes an instance of struct fb_info
as parameter, it really only needs the contained fbcon state. Moving the
call to fbcon initialization is therefore cleaner than before. Only amdgpu,
i915, nouveau and radeon support vga_switcheroo. For all other drivers,
this change does nothing.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://elixir.bootlin.com/linux/v6.17/source/drivers/video/fbdev/core/fbcon.c#L2942 # [1]
Fixes: 6a9ee8af34 ("vga_switcheroo: initial implementation (v15)")
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: <stable@vger.kernel.org> # v2.6.34+
Link: https://patch.msgid.link/20251105161549.98836-1-tzimmermann@suse.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:25:03 +09:00
Albin Babu Varghese 15ba9acafb fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds
[ Upstream commit 3637d34b35 ]

Add bounds checking to prevent writes past framebuffer boundaries when
rendering text near screen edges. Return early if the Y position is off-screen
and clip image height to screen boundary. Break from the rendering loop if the
X position is off-screen. When clipping image width to fit the screen, update
the character count to match the clipped width to prevent buffer size
mismatches.

Without the character count update, bit_putcs_aligned and bit_putcs_unaligned
receive mismatched parameters where the buffer is allocated for the clipped
width but cnt reflects the original larger count, causing out-of-bounds writes.

Reported-by: syzbot+48b0652a95834717f190@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=48b0652a95834717f190
Suggested-by: Helge Deller <deller@gmx.de>
Tested-by: syzbot+48b0652a95834717f190@syzkaller.appspotmail.com
Signed-off-by: Albin Babu Varghese <albinbabuvarghese20@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-13 15:34:35 -05:00
Miaoqian Lin 3ea7b3a697 fbdev: valkyriefb: Fix reference count leak in valkyriefb_init
commit eb53368f8d upstream.

The of_find_node_by_name() function returns a device tree node with its
reference count incremented. The caller is responsible for calling
of_node_put() to release this reference when done.

Found via static analysis.

Fixes: cc5d0189b9 ("[PATCH] powerpc: Remove device_node addrs/n_addr")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Florian Fuchs a22bcb7f10 fbdev: pvr2fb: Fix leftover reference to ONCHIP_NR_DMA_CHANNELS
commit 5f566c0ac5 upstream.

Commit e24cca19ba ("sh: Kill off MAX_DMA_ADDRESS leftovers.") removed
the define ONCHIP_NR_DMA_CHANNELS. So that the leftover reference needs
to be replaced by CONFIG_NR_ONCHIP_DMA_CHANNELS to compile successfully
with CONFIG_PVR2_DMA enabled.

Signed-off-by: Florian Fuchs <fuchsfl@gmail.com>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Junjie Cao 901f442270 fbdev: bitblit: bound-check glyph index in bit_putcs*
commit 18c4ef4e76 upstream.

bit_putcs_aligned()/unaligned() derived the glyph pointer from the
character value masked by 0xff/0x1ff, which may exceed the actual font's
glyph count and read past the end of the built-in font array.
Clamp the index to the actual glyph count before computing the address.

This fixes a global out-of-bounds read reported by syzbot.

Reported-by: syzbot+793cf822d213be1a74f2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=793cf822d213be1a74f2
Tested-by: syzbot+793cf822d213be1a74f2@syzkaller.appspotmail.com
Signed-off-by: Junjie Cao <junjie.cao@intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Daniel Palmer 9280286e04 fbdev: atyfb: Check if pll_ops->init_pll failed
commit 7073c7fc8d upstream.

Actually check the return value from pll_ops->init_pll()
as it can return an error.

If the card's BIOS didn't run because it's not the primary VGA card
the fact that the xclk source is unsupported is printed as shown
below but the driver continues on regardless and on my machine causes
a hard lock up.

[   61.470088] atyfb 0000:03:05.0: enabling device (0080 -> 0083)
[   61.476191] atyfb: using auxiliary register aperture
[   61.481239] atyfb: 3D RAGE XL (Mach64 GR, PCI-33) [0x4752 rev 0x27]
[   61.487569] atyfb: 512K SGRAM (1:1), 14.31818 MHz XTAL, 230 MHz PLL, 83 Mhz MCLK, 63 MHz XCLK
[   61.496112] atyfb: Unsupported xclk source:  5.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Quanmin Yan c079d42f70 fbcon: Set fb_display[i]->mode to NULL when the mode is released
commit a1f3058930 upstream.

Recently, we discovered the following issue through syzkaller:

BUG: KASAN: slab-use-after-free in fb_mode_is_equal+0x285/0x2f0
Read of size 4 at addr ff11000001b3c69c by task syz.xxx
...
Call Trace:
 <TASK>
 dump_stack_lvl+0xab/0xe0
 print_address_description.constprop.0+0x2c/0x390
 print_report+0xb9/0x280
 kasan_report+0xb8/0xf0
 fb_mode_is_equal+0x285/0x2f0
 fbcon_mode_deleted+0x129/0x180
 fb_set_var+0xe7f/0x11d0
 do_fb_ioctl+0x6a0/0x750
 fb_ioctl+0xe0/0x140
 __x64_sys_ioctl+0x193/0x210
 do_syscall_64+0x5f/0x9c0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Based on experimentation and analysis, during framebuffer unregistration,
only the memory of fb_info->modelist is freed, without setting the
corresponding fb_display[i]->mode to NULL for the freed modes. This leads
to UAF issues during subsequent accesses. Here's an example of reproduction
steps:
1. With /dev/fb0 already registered in the system, load a kernel module
   to register a new device /dev/fb1;
2. Set fb1's mode to the global fb_display[] array (via FBIOPUT_CON2FBMAP);
3. Switch console from fb to VGA (to allow normal rmmod of the ko);
4. Unload the kernel module, at this point fb1's modelist is freed, leaving
   a wild pointer in fb_display[];
5. Trigger the bug via system calls through fb0 attempting to delete a mode
   from fb0.

Add a check in do_unregister_framebuffer(): if the mode to be freed exists
in fb_display[], set the corresponding mode pointer to NULL.

Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Finn Thain f7cf0d7747 fbdev: Fix logic error in "offb" name match
commit 15df28699b upstream.

A regression was reported to me recently whereby /dev/fb0 had disappeared
from a PowerBook G3 Series "Wallstreet". The problem shows up when the
"video=ofonly" parameter is passed to the kernel, which is what the
bootloader does when "no video driver" is selected. The cause of the
problem is the "offb" string comparison, which got mangled when it got
refactored. Fix it.

Cc: stable@vger.kernel.org
Fixes: 93604a5ade ("fbdev: Handle video= parameter in video/cmdline.c")
Reported-and-tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-19 16:33:49 +02:00
Janne Grunau b1deb39cfd fbdev: simplefb: Fix use after free in simplefb_detach_genpds()
commit da1bb91352 upstream.

The pm_domain cleanup can not be devres managed as it uses struct
simplefb_par which is allocated within struct fb_info by
framebuffer_alloc(). This allocation is explicitly freed by
unregister_framebuffer() in simplefb_remove().
Devres managed cleanup runs after the device remove call and thus can no
longer access struct simplefb_par.
Call simplefb_detach_genpds() explicitly from simplefb_destroy() like
the cleanup functions for clocks and regulators.

Fixes an use after free on M2 Mac mini during
aperture_remove_conflicting_devices() using the downstream asahi kernel
with Debian's kernel config. For unknown reasons this started to
consistently dereference an invalid pointer in v6.16.3 based kernels.

[    6.736134] BUG: KASAN: slab-use-after-free in simplefb_detach_genpds+0x58/0x220
[    6.743545] Read of size 4 at addr ffff8000304743f0 by task (udev-worker)/227
[    6.750697]
[    6.752182] CPU: 6 UID: 0 PID: 227 Comm: (udev-worker) Tainted: G S                  6.16.3-asahi+ #16 PREEMPTLAZY
[    6.752186] Tainted: [S]=CPU_OUT_OF_SPEC
[    6.752187] Hardware name: Apple Mac mini (M2, 2023) (DT)
[    6.752189] Call trace:
[    6.752190]  show_stack+0x34/0x98 (C)
[    6.752194]  dump_stack_lvl+0x60/0x80
[    6.752197]  print_report+0x17c/0x4d8
[    6.752201]  kasan_report+0xb4/0x100
[    6.752206]  __asan_report_load4_noabort+0x20/0x30
[    6.752209]  simplefb_detach_genpds+0x58/0x220
[    6.752213]  devm_action_release+0x50/0x98
[    6.752216]  release_nodes+0xd0/0x2c8
[    6.752219]  devres_release_all+0xfc/0x178
[    6.752221]  device_unbind_cleanup+0x28/0x168
[    6.752224]  device_release_driver_internal+0x34c/0x470
[    6.752228]  device_release_driver+0x20/0x38
[    6.752231]  bus_remove_device+0x1b0/0x380
[    6.752234]  device_del+0x314/0x820
[    6.752238]  platform_device_del+0x3c/0x1e8
[    6.752242]  platform_device_unregister+0x20/0x50
[    6.752246]  aperture_detach_platform_device+0x1c/0x30
[    6.752250]  aperture_detach_devices+0x16c/0x290
[    6.752253]  aperture_remove_conflicting_devices+0x34/0x50
...
[    6.752343]
[    6.967409] Allocated by task 62:
[    6.970724]  kasan_save_stack+0x3c/0x70
[    6.974560]  kasan_save_track+0x20/0x40
[    6.978397]  kasan_save_alloc_info+0x40/0x58
[    6.982670]  __kasan_kmalloc+0xd4/0xd8
[    6.986420]  __kmalloc_noprof+0x194/0x540
[    6.990432]  framebuffer_alloc+0xc8/0x130
[    6.994444]  simplefb_probe+0x258/0x2378
...
[    7.054356]
[    7.055838] Freed by task 227:
[    7.058891]  kasan_save_stack+0x3c/0x70
[    7.062727]  kasan_save_track+0x20/0x40
[    7.066565]  kasan_save_free_info+0x4c/0x80
[    7.070751]  __kasan_slab_free+0x6c/0xa0
[    7.074675]  kfree+0x10c/0x380
[    7.077727]  framebuffer_release+0x5c/0x90
[    7.081826]  simplefb_destroy+0x1b4/0x2c0
[    7.085837]  put_fb_info+0x98/0x100
[    7.089326]  unregister_framebuffer+0x178/0x320
[    7.093861]  simplefb_remove+0x3c/0x60
[    7.097611]  platform_remove+0x60/0x98
[    7.101361]  device_remove+0xb8/0x160
[    7.105024]  device_release_driver_internal+0x2fc/0x470
[    7.110256]  device_release_driver+0x20/0x38
[    7.114529]  bus_remove_device+0x1b0/0x380
[    7.118628]  device_del+0x314/0x820
[    7.122116]  platform_device_del+0x3c/0x1e8
[    7.126302]  platform_device_unregister+0x20/0x50
[    7.131012]  aperture_detach_platform_device+0x1c/0x30
[    7.136157]  aperture_detach_devices+0x16c/0x290
[    7.140779]  aperture_remove_conflicting_devices+0x34/0x50
...

Reported-by: Daniel Huhardeaux <tech@tootai.net>
Cc: stable@vger.kernel.org
Fixes: 92a511a568 ("fbdev/simplefb: Add support for generic power-domains")
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-15 12:00:23 +02:00
Thomas Zimmermann 51b8258efe fbcon: Fix OOB access in font allocation
commit 9b2f5ef00e upstream.

Commit 1a194e6c8e ("fbcon: fix integer overflow in fbcon_do_set_font")
introduced an out-of-bounds access by storing data and allocation sizes
in the same variable. Restore the old size calculation and use the new
variable 'alloc_size' for the allocation.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 1a194e6c8e ("fbcon: fix integer overflow in fbcon_do_set_font")
Reported-by: Jani Nikula <jani.nikula@linux.intel.com>
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15020
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6201
Cc: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: George Kennedy <george.kennedy@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Shixiong Ou <oushixiong@kylinos.cn>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org> # v5.9+
Cc: Zsolt Kajtar <soci@c64.rulez.org>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Qianqiang Liu <qianqiang.liu@163.com>
Link: https://lore.kernel.org/r/20250922134619.257684-1-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-02 13:44:14 +02:00
Samasth Norway Ananda 4a4bac8695 fbcon: fix integer overflow in fbcon_do_set_font
commit 1a194e6c8e upstream.

Fix integer overflow vulnerabilities in fbcon_do_set_font() where font
size calculations could overflow when handling user-controlled font
parameters.

The vulnerabilities occur when:
1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount
   multiplication with user-controlled values that can overflow.
2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow
3. This results in smaller allocations than expected, leading to buffer
   overflows during font data copying.

Add explicit overflow checking using check_mul_overflow() and
check_add_overflow() kernel helpers to safety validate all size
calculations before allocation.

Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 39b3cffb8c ("fbcon: prevent user font height or width change from causing potential out-of-bounds access")
Cc: George Kennedy <george.kennedy@oracle.com>
Cc: stable <stable@vger.kernel.org>
Cc: syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Shixiong Ou <oushixiong@kylinos.cn>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org> # v5.9+
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250912170023.3931881-1-samasth.norway.ananda@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-02 13:44:14 +02:00
Sravan Kumar Gundu ed9b8e5016 fbdev: Fix vmalloc out-of-bounds write in fast_imageblit
commit af0db3c1f8 upstream.

This issue triggers when a userspace program does an ioctl
FBIOPUT_CON2FBMAP by passing console number and frame buffer number.
Ideally this maps console to frame buffer and updates the screen if
console is visible.

As part of mapping it has to do resize of console according to frame
buffer info. if this resize fails and returns from vc_do_resize() and
continues further. At this point console and new frame buffer are mapped
and sets display vars. Despite failure still it continue to proceed
updating the screen at later stages where vc_data is related to previous
frame buffer and frame buffer info and display vars are mapped to new
frame buffer and eventully leading to out-of-bounds write in
fast_imageblit(). This bheviour is excepted only when fg_console is
equal to requested console which is a visible console and updates screen
with invalid struct references in fbcon_putcs().

Reported-and-tested-by: syzbot+c4b7aa0513823e2ea880@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c4b7aa0513823e2ea880
Signed-off-by: Sravan Kumar Gundu <sravankumarlpu@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-20 18:30:54 +02:00
Yongzhen Zhang 806f85bdd3 fbdev: fix potential buffer overflow in do_register_framebuffer()
[ Upstream commit 523b84dc7c ]

The current implementation may lead to buffer overflow when:
1.  Unregistration creates NULL gaps in registered_fb[]
2.  All array slots become occupied despite num_registered_fb < FB_MAX
3.  The registration loop exceeds array bounds

Add boundary check to prevent registered_fb[FB_MAX] access.

Signed-off-by: Yongzhen Zhang <zhangyongzhen@kylinos.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-20 18:30:40 +02:00
Chenyuan Yang 40f0a51f6c fbdev: imxfb: Check fb_add_videomode to prevent null-ptr-deref
[ Upstream commit da11e6a30e ]

fb_add_videomode() can fail with -ENOMEM when its internal kmalloc() cannot
allocate a struct fb_modelist.  If that happens, the modelist stays empty but
the driver continues to register.  Add a check for its return value to prevent
poteintial null-ptr-deref, which is similar to the commit 17186f1f90 ("fbdev:
Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_var").

Fixes: 1b6c79361b ("video: imxfb: Add DT support")
Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-15 12:13:57 +02:00
Shixiong Ou 69be0a3c4e fbcon: Fix outdated registered_fb reference in comment
[ Upstream commit 0f168e7be6 ]

The variable was renamed to fbcon_registered_fb, but this comment was
not updated along with the change. Correct it to avoid confusion.

Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Fixes: efc3acbc10 ("fbcon: Maintain a private array of fb_info")
[sima: Add Fixes: line.]
Signed-off-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20250709103438.572309-1-oushixiong1025@163.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-15 12:13:42 +02:00
Kees Cook f28f1f578c fbcon: Make sure modelist not set on unregistered console
[ Upstream commit cedc1b6339 ]

It looks like attempting to write to the "store_modes" sysfs node will
run afoul of unregistered consoles:

UBSAN: array-index-out-of-bounds in drivers/video/fbdev/core/fbcon.c:122:28
index -1 is out of range for type 'fb_info *[32]'
...
 fbcon_info_from_console+0x192/0x1a0 drivers/video/fbdev/core/fbcon.c:122
 fbcon_new_modelist+0xbf/0x2d0 drivers/video/fbdev/core/fbcon.c:3048
 fb_new_modelist+0x328/0x440 drivers/video/fbdev/core/fbmem.c:673
 store_modes+0x1c9/0x3e0 drivers/video/fbdev/core/fbsysfs.c:113
 dev_attr_store+0x55/0x80 drivers/base/core.c:2439

static struct fb_info *fbcon_registered_fb[FB_MAX];
...
static signed char con2fb_map[MAX_NR_CONSOLES];
...
static struct fb_info *fbcon_info_from_console(int console)
...
        return fbcon_registered_fb[con2fb_map[console]];

If con2fb_map contains a -1 things go wrong here. Instead, return NULL,
as callers of fbcon_info_from_console() are trying to compare against
existing "info" pointers, so error handling should kick in correctly.

Reported-by: syzbot+a7d4444e7b6e743572f7@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/679d0a8f.050a0220.163cdc.000c.GAE@google.com/
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27 11:11:35 +01:00
Murad Masimov b3071bb463 fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var
commit 05f6e18387 upstream.

If fb_add_videomode() in fb_set_var() fails to allocate memory for
fb_videomode, later it may lead to a null-ptr dereference in
fb_videomode_to_var(), as the fb_info is registered while not having the
mode in modelist that is expected to be there, i.e. the one that is
described in fb_info->var.

================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901
Call Trace:
 display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929
 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071
 resize_screen drivers/tty/vt/vt.c:1176 [inline]
 vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263
 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720
 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776
 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1
================================================================

The reason is that fb_info->var is being modified in fb_set_var(), and
then fb_videomode_to_var() is called. If it fails to add the mode to
fb_info->modelist, fb_set_var() returns error, but does not restore the
old value of fb_info->var. Restore fb_info->var on failure the same way
it is done earlier in the function.

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

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:21 +01:00
Murad Masimov 3f2098f4fb fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_var
commit 17186f1f90 upstream.

If fb_add_videomode() in do_register_framebuffer() fails to allocate
memory for fb_videomode, it will later lead to a null-ptr dereference in
fb_videomode_to_var(), as the fb_info is registered while not having the
mode in modelist that is expected to be there, i.e. the one that is
described in fb_info->var.

================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901
Call Trace:
 display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929
 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071
 resize_screen drivers/tty/vt/vt.c:1176 [inline]
 vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263
 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720
 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776
 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1
================================================================

Even though fbcon_init() checks beforehand if fb_match_mode() in
var_to_display() fails, it can not prevent the panic because fbcon_init()
does not return error code. Considering this and the comment in the code
about fb_match_mode() returning NULL - "This should not happen" - it is
better to prevent registering the fb_info if its mode was not set
successfully. Also move fb_add_videomode() closer to the beginning of
do_register_framebuffer() to avoid having to do the cleanup on fail.

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

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:21 +01:00
Sergey Shtylyov b235393b9f fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()
[ Upstream commit 3f6dae09fc ]

In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000,
cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It's
then passed to fb_cvt_hperiod(), where it's used as a divider -- division
by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to
avoid such overflow...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Fixes: 96fe6a2109 ("[PATCH] fbdev: Add VESA Coordinated Video Timings (CVT) support")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19 15:32:03 +02:00
Zsolt Kajtar ff968e486e fbdev: core: tileblit: Implement missing margin clearing for tileblit
[ Upstream commit 76d3ca8998 ]

I was wondering why there's garbage at the bottom of the screen when
tile blitting is used with an odd mode like 1080, 600 or 200. Sure there's
only space for half a tile but the same area is clean when the buffer
is bitmap.

Then later I found that it's supposed to be cleaned but that's not
implemented. So I took what's in bitblit and adapted it for tileblit.

This implementation was tested for both the horizontal and vertical case,
and now does the same as what's done for bitmap buffers.

If anyone is interested to reproduce the problem then I could bet that'd
be on a S3 or Ark. Just set up a mode with an odd line count and make
sure that the virtual size covers the complete tile at the bottom. E.g.
for 600 lines that's 608 virtual lines for a 16 tall tile. Then the
bottom area should be cleaned.

For the right side it's more difficult as there the drivers won't let an
odd size happen, unless the code is modified. But once it reports back a
few pixel columns short then fbcon won't use the last column. With the
patch that column is now clean.

Btw. the virtual size should be rounded up by the driver for both axes
(not only the horizontal) so that it's dividable by the tile size.
That's a driver bug but correcting it is not in scope for this patch.

Implement missing margin clearing for tileblit

Signed-off-by: Zsolt Kajtar <soci@c64.rulez.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:05 +02:00
Zsolt Kajtar 8c912c0a68 fbcon: Use correct erase colour for clearing in fbcon
[ Upstream commit 892c788d73 ]

The erase colour calculation for fbcon clearing should use get_color instead
of attr_col_ec, like everything else. The latter is similar but is not correct.
For example it's missing the depth dependent remapping and doesn't care about
blanking.

The problem can be reproduced by setting up the background colour to grey
(vt.color=0x70) and having an fbcon console set to 2bpp (4 shades of gray).
Now the background attribute should be 1 (dark gray) on the console.

If the screen is scrolled when pressing enter in a shell prompt at the bottom
line then the new line is cleared using colour 7 instead of 1. That's not
something fillrect likes (at 2bbp it expect 0-3) so the result is interesting.

This patch switches to get_color with vc_video_erase_char to determine the
erase colour from attr_col_ec. That makes the latter function redundant as
no other users were left.

Use correct erase colour for clearing in fbcon

Signed-off-by: Zsolt Kajtar <soci@c64.rulez.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:05 +02:00
Shixiong Ou 230abe5d3f fbdev: fsl-diu-fb: add missing device_remove_file()
[ Upstream commit 86d16cd12e ]

Call device_remove_file() when driver remove.

Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:05 +02:00
Leonid Arapov 52eafaa56f fbdev: omapfb: Add 'plane' value check
[ Upstream commit 3e411827f3 ]

Function dispc_ovl_setup is not intended to work with the value OMAP_DSS_WB
of the enum parameter plane.

The value of this parameter is initialized in dss_init_overlays and in the
current state of the code it cannot take this value so it's not a real
problem.

For the purposes of defensive coding it wouldn't be superfluous to check
the parameter value, because some functions down the call stack process
this value correctly and some not.

For example, in dispc_ovl_setup_global_alpha it may lead to buffer
overflow.

Add check for this value.

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

Signed-off-by: Leonid Arapov <arapovl839@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-20 10:15:27 +02:00
Danila Chernetsov 238ece4937 fbdev: sm501fb: Add some geometry checks.
[ Upstream commit aee50bd88e ]

Added checks for xoffset, yoffset settings.
Incorrect settings of these parameters can lead to errors
in sm501fb_pan_ functions.

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

Fixes: 5fc404e47b ("[PATCH] fb: SM501 framebuffer driver")
Signed-off-by: Danila Chernetsov <listdansp@mail.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:17 +02:00
Markus Elfring 9a14cacaf5 fbdev: au1100fb: Move a variable assignment behind a null pointer check
[ Upstream commit 2df2c0caae ]

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “au1100fb_setmode”.

This issue was detected by using the Coccinelle software.

Fixes: 3b495f2bb7 ("Au1100 FB driver uplift for 2.6.")
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:16 +02:00
Saurabh Sengar 4545e2aa12 fbdev: hyperv_fb: Allow graceful removal of framebuffer
[ Upstream commit ea2f45ab0e ]

When a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to
release the framebuffer forcefully. If this framebuffer is in use it
produce the following WARN and hence this framebuffer is never released.

[   44.111220] WARNING: CPU: 35 PID: 1882 at drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40
< snip >
[   44.111289] Call Trace:
[   44.111290]  <TASK>
[   44.111291]  ? show_regs+0x6c/0x80
[   44.111295]  ? __warn+0x8d/0x150
[   44.111298]  ? framebuffer_release+0x2c/0x40
[   44.111300]  ? report_bug+0x182/0x1b0
[   44.111303]  ? handle_bug+0x6e/0xb0
[   44.111306]  ? exc_invalid_op+0x18/0x80
[   44.111308]  ? asm_exc_invalid_op+0x1b/0x20
[   44.111311]  ? framebuffer_release+0x2c/0x40
[   44.111313]  ? hvfb_remove+0x86/0xa0 [hyperv_fb]
[   44.111315]  vmbus_remove+0x24/0x40 [hv_vmbus]
[   44.111323]  device_remove+0x40/0x80
[   44.111325]  device_release_driver_internal+0x20b/0x270
[   44.111327]  ? bus_find_device+0xb3/0xf0

Fix this by moving the release of framebuffer and assosiated memory
to fb_ops.fb_destroy function, so that framebuffer framework handles
it gracefully.

While we fix this, also replace manual registrations/unregistration of
framebuffer with devm_register_framebuffer.

Fixes: 68a2d20b79 ("drivers/video: add Hyper-V Synthetic Video Frame Buffer Driver")

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1740845791-19977-3-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1740845791-19977-3-git-send-email-ssengar@linux.microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22 12:54:11 -07:00
Saurabh Sengar ae83389070 fbdev: hyperv_fb: Simplify hvfb_putmem
[ Upstream commit f5e728a50b ]

The device object required in 'hvfb_release_phymem' function
for 'dma_free_coherent' can also be obtained from the 'info'
pointer, making 'hdev' parameter in 'hvfb_putmem' redundant.
Remove the unnecessary 'hdev' argument from 'hvfb_putmem'.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com>
Stable-dep-of: ea2f45ab0e ("fbdev: hyperv_fb: Allow graceful removal of framebuffer")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22 12:54:11 -07:00
Michael Kelley cfffe46a99 fbdev: hyperv_fb: Fix hang in kdump kernel when on Hyper-V Gen 2 VMs
[ Upstream commit 3043863730 ]

Gen 2 Hyper-V VMs boot via EFI and have a standard EFI framebuffer
device. When the kdump kernel runs in such a VM, loading the efifb
driver may hang because of accessing the framebuffer at the wrong
memory address.

The scenario occurs when the hyperv_fb driver in the original kernel
moves the framebuffer to a different MMIO address because of conflicts
with an already-running efifb or simplefb driver. The hyperv_fb driver
then informs Hyper-V of the change, which is allowed by the Hyper-V FB
VMBus device protocol. However, when the kexec command loads the kdump
kernel into crash memory via the kexec_file_load() system call, the
system call doesn't know the framebuffer has moved, and it sets up the
kdump screen_info using the original framebuffer address. The transition
to the kdump kernel does not go through the Hyper-V host, so Hyper-V
does not reset the framebuffer address like it would do on a reboot.
When efifb tries to run, it accesses a non-existent framebuffer
address, which traps to the Hyper-V host. After many such accesses,
the Hyper-V host thinks the guest is being malicious, and throttles
the guest to the point that it runs very slowly or appears to have hung.

When the kdump kernel is loaded into crash memory via the kexec_load()
system call, the problem does not occur. In this case, the kexec command
builds the screen_info table itself in user space from data returned
by the FBIOGET_FSCREENINFO ioctl against /dev/fb0, which gives it the
new framebuffer location.

This problem was originally reported in 2020 [1], resulting in commit
3cb73bc3fa ("hyperv_fb: Update screen_info after removing old
framebuffer"). This commit solved the problem by setting orig_video_isVGA
to 0, so the kdump kernel was unaware of the EFI framebuffer. The efifb
driver did not try to load, and no hang occurred. But in 2024, commit
c25a19afb8 ("fbdev/hyperv_fb: Do not clear global screen_info")
effectively reverted 3cb73bc3fa. Commit c25a19afb8 has no reference
to 3cb73bc3fa, so perhaps it was done without knowing the implications
that were reported with 3cb73bc3fa. In any case, as of commit
c25a19afb8, the original problem came back again.

Interestingly, the hyperv_drm driver does not have this problem because
it never moves the framebuffer. The difference is that the hyperv_drm
driver removes any conflicting framebuffers *before* allocating an MMIO
address, while the hyperv_fb drivers removes conflicting framebuffers
*after* allocating an MMIO address. With the "after" ordering, hyperv_fb
may encounter a conflict and move the framebuffer to a different MMIO
address. But the conflict is essentially bogus because it is removed
a few lines of code later.

Rather than fix the problem with the approach from 2020 in commit
3cb73bc3fa, instead slightly reorder the steps in hyperv_fb so
conflicting framebuffers are removed before allocating an MMIO address.
Then the default framebuffer MMIO address should always be available, and
there's never any confusion about which framebuffer address the kdump
kernel should use -- it's always the original address provided by
the Hyper-V host. This approach is already used by the hyperv_drm
driver, and is consistent with the usage guidelines at the head of
the module with the function aperture_remove_conflicting_devices().

This approach also solves a related minor problem when kexec_load()
is used to load the kdump kernel. With current code, unbinding and
rebinding the hyperv_fb driver could result in the framebuffer moving
back to the default framebuffer address, because on the rebind there
are no conflicts. If such a move is done after the kdump kernel is
loaded with the new framebuffer address, at kdump time it could again
have the wrong address.

This problem and fix are described in terms of the kdump kernel, but
it can also occur with any kernel started via kexec.

See extensive discussion of the problem and solution at [2].

[1] https://lore.kernel.org/linux-hyperv/20201014092429.1415040-1-kasong@redhat.com/
[2] https://lore.kernel.org/linux-hyperv/BLAPR10MB521793485093FDB448F7B2E5FDE92@BLAPR10MB5217.namprd10.prod.outlook.com/

Reported-by: Thomas Tai <thomas.tai@oracle.com>
Fixes: c25a19afb8 ("fbdev/hyperv_fb: Do not clear global screen_info")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20250218230130.3207-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250218230130.3207-1-mhklinux@outlook.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22 12:54:11 -07:00
Michael Kelley ea8411db9f fbdev: hyperv_fb: iounmap() the correct memory when removing a device
[ Upstream commit 7241c886a7 ]

When a Hyper-V framebuffer device is removed, or the driver is unbound
from a device, any allocated and/or mapped memory must be released. In
particular, MMIO address space that was mapped to the framebuffer must
be unmapped. Current code unmaps the wrong address, resulting in an
error like:

[ 4093.980597] iounmap: bad address 00000000c936c05c

followed by a stack dump.

Commit d21987d709 ("video: hyperv: hyperv_fb: Support deferred IO for
Hyper-V frame buffer driver") changed the kind of address stored in
info->screen_base, and the iounmap() call in hvfb_putmem() was not
updated accordingly.

Fix this by updating hvfb_putmem() to unmap the correct address.

Fixes: d21987d709 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250209235252.2987-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250209235252.2987-1-mhklinux@outlook.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22 12:54:09 -07:00
Aaro Koskinen aa8e22cbed fbdev: omap: use threaded IRQ for LCD DMA
[ Upstream commit e4b6b665df ]

When using touchscreen and framebuffer, Nokia 770 crashes easily with:

    BUG: scheduling while atomic: irq/144-ads7846/82/0x00010000
    Modules linked in: usb_f_ecm g_ether usb_f_rndis u_ether libcomposite configfs omap_udc ohci_omap ohci_hcd
    CPU: 0 UID: 0 PID: 82 Comm: irq/144-ads7846 Not tainted 6.12.7-770 #2
    Hardware name: Nokia 770
    Call trace:
     unwind_backtrace from show_stack+0x10/0x14
     show_stack from dump_stack_lvl+0x54/0x5c
     dump_stack_lvl from __schedule_bug+0x50/0x70
     __schedule_bug from __schedule+0x4d4/0x5bc
     __schedule from schedule+0x34/0xa0
     schedule from schedule_preempt_disabled+0xc/0x10
     schedule_preempt_disabled from __mutex_lock.constprop.0+0x218/0x3b4
     __mutex_lock.constprop.0 from clk_prepare_lock+0x38/0xe4
     clk_prepare_lock from clk_set_rate+0x18/0x154
     clk_set_rate from sossi_read_data+0x4c/0x168
     sossi_read_data from hwa742_read_reg+0x5c/0x8c
     hwa742_read_reg from send_frame_handler+0xfc/0x300
     send_frame_handler from process_pending_requests+0x74/0xd0
     process_pending_requests from lcd_dma_irq_handler+0x50/0x74
     lcd_dma_irq_handler from __handle_irq_event_percpu+0x44/0x130
     __handle_irq_event_percpu from handle_irq_event+0x28/0x68
     handle_irq_event from handle_level_irq+0x9c/0x170
     handle_level_irq from generic_handle_domain_irq+0x2c/0x3c
     generic_handle_domain_irq from omap1_handle_irq+0x40/0x8c
     omap1_handle_irq from generic_handle_arch_irq+0x28/0x3c
     generic_handle_arch_irq from call_with_stack+0x1c/0x24
     call_with_stack from __irq_svc+0x94/0xa8
    Exception stack(0xc5255da0 to 0xc5255de8)
    5da0: 00000001 c22fc620 00000000 00000000 c08384a8 c106fc00 00000000 c240c248
    5dc0: c113a600 c3f6ec30 00000001 00000000 c22fc620 c5255df0 c22fc620 c0279a94
    5de0: 60000013 ffffffff
     __irq_svc from clk_prepare_lock+0x4c/0xe4
     clk_prepare_lock from clk_get_rate+0x10/0x74
     clk_get_rate from uwire_setup_transfer+0x40/0x180
     uwire_setup_transfer from spi_bitbang_transfer_one+0x2c/0x9c
     spi_bitbang_transfer_one from spi_transfer_one_message+0x2d0/0x664
     spi_transfer_one_message from __spi_pump_transfer_message+0x29c/0x498
     __spi_pump_transfer_message from __spi_sync+0x1f8/0x2e8
     __spi_sync from spi_sync+0x24/0x40
     spi_sync from ads7846_halfd_read_state+0x5c/0x1c0
     ads7846_halfd_read_state from ads7846_irq+0x58/0x348
     ads7846_irq from irq_thread_fn+0x1c/0x78
     irq_thread_fn from irq_thread+0x120/0x228
     irq_thread from kthread+0xc8/0xe8
     kthread from ret_from_fork+0x14/0x28

As a quick fix, switch to a threaded IRQ which provides a stable system.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21 14:01:22 +01:00
Joe Hattori 873f6bdf23 fbdev: omapfb: Fix an OF node leak in dss_of_port_get_parent_device()
[ Upstream commit de124b61e1 ]

dss_of_port_get_parent_device() leaks an OF node reference when i >= 2
and struct device_node *np is present. Since of_get_next_parent()
obtains a reference of the returned OF node, call of_node_put() before
returning NULL.

This was found by an experimental verifier that I am developing, and no
runtime test was able to be performed due to that lack of actual
devices.

Fixes: f76ee892a9 ("omapfb: copy omapdss & displays for omapfb")
Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08 09:57:50 +01:00
Zhen Lei bad37309c8 fbdev: sh7760fb: Fix a possible memory leak in sh7760fb_alloc_mem()
[ Upstream commit f89d17ae2a ]

When information such as info->screen_base is not ready, calling
sh7760fb_free_mem() does not release memory correctly. Call
dma_free_coherent() instead.

Fixes: 4a25e41831 ("video: sh7760fb: SH7760/SH7763 LCDC framebuffer driver")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05 14:02:14 +01:00
Arnd Bergmann 51521d2e2c fbdev: wm8505fb: select CONFIG_FB_IOMEM_FOPS
The fb_io_mmap() function is used in the file operations but
not enabled in all configurations unless FB_IOMEM_FOPS gets
selected:

ld.lld-20: error: undefined symbol: fb_io_mmap
   referenced by wm8505fb.c
   drivers/video/fbdev/wm8505fb.o:(wm8505fb_ops) in archive vmlinux.a

Fixes: 11754a5046 ("fbdev/wm8505fb: Initialize fb_ops to fbdev I/O-memory helpers")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2024-10-21 11:16:51 +02:00
Bartosz Golaszewski bb94f56b9c fbdev: da8xx: remove the driver
This driver is no longer used on any platform. It has been replaced by
tilcdc on the two DaVinci boards we still support and can be removed.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2024-10-15 10:08:23 +02:00
Christophe JAILLET 161e95b899 fbdev: Constify struct sbus_mmap_map
'struct sbus_mmap_map' are not modified in these drivers.

Constifying this structure moves some data to a read-only section, so
increases overall security.

Update sbusfb_mmap_helper() accordingly.

On a x86_64, with allmodconfig, as an example:
Before:
======
   text	   data	    bss	    dec	    hex	filename
   2452	    536	     16	   3004	    bbc	drivers/video/fbdev/bw2.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
   2500	    483	     16	   2999	    bb7	drivers/video/fbdev/bw2.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Helge Deller <deller@gmx.de>
2024-10-15 10:07:32 +02:00