kernel/linux.git/drivers/video/fbdev, branch v5.15.209

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

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

2026-06-01T15:35:04+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: Set fb_display[i]->mode to NULL when the mode is released

2026-04-18T08:33:35+00:00

[ Upstream commit a1f3058930745d2b938b6b4f5bd9630dc74b26b7 ] 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: 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. [ The context change is due to the commit 2c0c19b681d5 ("fbdev: fbmem: Fix double free of 'fb_info->pixmap.addr'") in v5.16 which is irrelevant to the logic of this patch. ] Signed-off-by: Quanmin Yan Reviewed-by: Thomas Zimmermann Signed-off-by: Helge Deller Cc: stable@vger.kernel.org Signed-off-by: Johnny Hao Signed-off-by: Sasha Levin

fbcon: check return value of con2fb_acquire_newinfo()

2026-04-18T08:33:08+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

fbcon: move more common code into fb_open()

2026-04-18T08:33:08+00:00

[ Upstream commit d443d93864726ad68c0a741d1e7b03934a9af143 ] No idea why con2fb_acquire_newinfo() initializes much less than fbcon_startup(), but so be it. From a quick look most of the un-initialized stuff should be fairly harmless, but who knows. Note that the error handling for the con2fb_acquire_newinfo() failure case was very strange: Callers updated con2fb_map to the new value before calling this function, but upon error con2fb_acquire_newinfo reset it to the old value. Since I removed the call to fbcon_release anyway that strange error path was sticking out like a sore thumb, hence I removed it. Which also allows us to remove the oldidx parameter from that function. v2: Explain what's going on with oldidx and error paths (Sam) v3: Drop unused variable (0day) v4: Rebased over bisect fix in previous patch, unchagend end result. Acked-by: Sam Ravnborg (v2) Acked-by: Thomas Zimmermann Cc: kernel test robot Signed-off-by: Daniel Vetter Cc: Daniel Vetter Cc: Greg Kroah-Hartman Cc: Tetsuo Handa Cc: Thomas Zimmermann Cc: Claudio Suarez Cc: Du Cheng Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-12-daniel.vetter@ffwll.ch Stable-dep-of: 011a0502801c ("fbcon: check return value of con2fb_acquire_newinfo()") Signed-off-by: Sasha Levin

fbcon: Extract fbcon_open/release helpers

2026-04-18T08:33:07+00:00

[ Upstream commit bd6026a8c4e6b7edf4bafcb71da885b284b8f4fd ] There's two minor behaviour changes in here: - in error paths we now consistently call fb_ops->fb_release - fb_release really can't fail (fbmem.c ignores it too) and there's no reasonable cleanup we can do anyway. Note that everything in fbcon.c is protected by the big console_lock() lock (especially all the global variables), so the minor changes in ordering of setup/cleanup do not matter. v2: Explain a bit better why this is all correct (Sam) Acked-by: Sam Ravnborg Signed-off-by: Daniel Vetter Cc: Daniel Vetter Cc: Claudio Suarez Cc: Greg Kroah-Hartman Cc: Tetsuo Handa Cc: Du Cheng Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-10-daniel.vetter@ffwll.ch Stable-dep-of: 011a0502801c ("fbcon: check return value of con2fb_acquire_newinfo()") Signed-off-by: Sasha Levin