<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/video/fbdev/core, branch v6.18.32</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>fbcon: Avoid OOB font access if console rotation fails</title>
<updated>2026-05-17T15:15:35+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2026-05-14T17:58:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7105d9f1387d63b15c9a860674fc92c959181f2f'/>
<id>7105d9f1387d63b15c9a860674fc92c959181f2f</id>
<content type='text'>
[ 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 &lt;tzimmermann@suse.de&gt;
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 &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ 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 &lt;tzimmermann@suse.de&gt;
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 &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fbcon: Rename struct fbcon_ops to struct fbcon_par</title>
<updated>2026-05-17T15:15:35+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2026-05-14T17:58:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1817dd0c350f5918e4c66a0eb5bf6426e619b065'/>
<id>1817dd0c350f5918e4c66a0eb5bf6426e619b065</id>
<content type='text'>
[ Upstream commit a6adbbc4c32a016146e117b1e9e5242724a75e10 ]

The type struct fbcon_ops contains fbcon state and callbacks. As the
callbacks will be removed from struct fbcon_ops, rename the data type
to struct fbcon_par. Also rename the variables from ops to par.

The _par postfix ("private access registers") is used throughout the
fbdev subsystem for per-driver state. The fbcon pointer within struct
fb_info is also named fbcon_par. Hence, the new naming fits existing
practice.

v2:
- rename struct fbcon_ops to struct fbcon_par
- fix build for CONFIG_FB_TILEBITTING=n (kernel test robot)
- fix indention

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Link: https://lore.kernel.org/r/20250909124616.143365-3-tzimmermann@suse.de
Stable-dep-of: e4ef723d8975 ("fbcon: Avoid OOB font access if console rotation fails")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a6adbbc4c32a016146e117b1e9e5242724a75e10 ]

The type struct fbcon_ops contains fbcon state and callbacks. As the
callbacks will be removed from struct fbcon_ops, rename the data type
to struct fbcon_par. Also rename the variables from ops to par.

The _par postfix ("private access registers") is used throughout the
fbdev subsystem for per-driver state. The fbcon pointer within struct
fb_info is also named fbcon_par. Hence, the new naming fits existing
practice.

v2:
- rename struct fbcon_ops to struct fbcon_par
- fix build for CONFIG_FB_TILEBITTING=n (kernel test robot)
- fix indention

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Link: https://lore.kernel.org/r/20250909124616.143365-3-tzimmermann@suse.de
Stable-dep-of: e4ef723d8975 ("fbcon: Avoid OOB font access if console rotation fails")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info</title>
<updated>2026-05-14T13:30:25+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2026-05-04T14:19:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=25c2b77bc463f29ee71a54b883548baf9386a0db'/>
<id>25c2b77bc463f29ee71a54b883548baf9386a0db</id>
<content type='text'>
[ 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 &lt;tzimmermann@suse.de&gt;
Fixes: 60b59beafba8 ("fbdev: mm: Deferred IO support")
Cc: Helge Deller &lt;deller@gmx.de&gt;
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 &lt;deller@gmx.de&gt;
[ replaced kzalloc_obj(*fbdefio_state) with kzalloc(sizeof(*fbdefio_state), GFP_KERNEL) ]
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ 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 &lt;tzimmermann@suse.de&gt;
Fixes: 60b59beafba8 ("fbdev: mm: Deferred IO support")
Cc: Helge Deller &lt;deller@gmx.de&gt;
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 &lt;deller@gmx.de&gt;
[ replaced kzalloc_obj(*fbdefio_state) with kzalloc(sizeof(*fbdefio_state), GFP_KERNEL) ]
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fbcon: Remove struct fbcon_display.inverse</title>
<updated>2026-03-04T12:21:32+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2026-02-09T16:15:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bcf40ce4666507703216de00a45e56155cc56f4e'/>
<id>bcf40ce4666507703216de00a45e56155cc56f4e</id>
<content type='text'>
[ Upstream commit 30baedeeeab524172abc0b58cb101e8df86b5be8 ]

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

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Cc: &lt;stable@vger.kernel.org&gt; # v6.0+
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 30baedeeeab524172abc0b58cb101e8df86b5be8 ]

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

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Cc: &lt;stable@vger.kernel.org&gt; # v6.0+
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fbcon: check return value of con2fb_acquire_newinfo()</title>
<updated>2026-03-04T12:21:31+00:00</updated>
<author>
<name>Andrey Vatoropin</name>
<email>a.vatoropin@crpt.ru</email>
</author>
<published>2025-12-17T09:11:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=11a93180a70bb3095a9bd80d113d9277e30d9959'/>
<id>11a93180a70bb3095a9bd80d113d9277e30d9959</id>
<content type='text'>
[ Upstream commit 011a0502801c8536f64141a2b61362c14f456544 ]

If fbcon_open() fails when called from con2fb_acquire_newinfo() then
info-&gt;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 &lt;a.vatoropin@crpt.ru&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 011a0502801c8536f64141a2b61362c14f456544 ]

If fbcon_open() fails when called from con2fb_acquire_newinfo() then
info-&gt;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 &lt;a.vatoropin@crpt.ru&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fbdev: Use device_create_with_groups() to fix sysfs groups registration race</title>
<updated>2026-03-04T12:21:31+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>johannes.goede@oss.qualcomm.com</email>
</author>
<published>2025-12-21T16:57:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0a08a7fa123c0c53d391833ad1c0757ee89d4ad2'/>
<id>0a08a7fa123c0c53d391833ad1c0757ee89d4ad2</id>
<content type='text'>
[ 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 &lt;oushixiong@kylinos.cn&gt;
Signed-off-by: Hans de Goede &lt;johannes.goede@oss.qualcomm.com&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ 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 &lt;oushixiong@kylinos.cn&gt;
Signed-off-by: Hans de Goede &lt;johannes.goede@oss.qualcomm.com&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup</title>
<updated>2025-11-25T08:08:32+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2025-11-05T16:14:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eb76d0f5553575599561010f24c277cc5b31d003'/>
<id>eb76d0f5553575599561010f24c277cc5b31d003</id>
<content type='text'>
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 &lt;tzimmermann@suse.de&gt;
Link: https://elixir.bootlin.com/linux/v6.17/source/drivers/video/fbdev/core/fbcon.c#L2942 # [1]
Fixes: 6a9ee8af344e ("vga_switcheroo: initial implementation (v15)")
Acked-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: &lt;stable@vger.kernel.org&gt; # v2.6.34+
Link: https://patch.msgid.link/20251105161549.98836-1-tzimmermann@suse.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;tzimmermann@suse.de&gt;
Link: https://elixir.bootlin.com/linux/v6.17/source/drivers/video/fbdev/core/fbcon.c#L2942 # [1]
Fixes: 6a9ee8af344e ("vga_switcheroo: initial implementation (v15)")
Acked-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: &lt;stable@vger.kernel.org&gt; # v2.6.34+
Link: https://patch.msgid.link/20251105161549.98836-1-tzimmermann@suse.de
</pre>
</div>
</content>
</entry>
<entry>
<title>fbcon: Set fb_display[i]-&gt;mode to NULL when the mode is released</title>
<updated>2025-10-28T21:59:19+00:00</updated>
<author>
<name>Quanmin Yan</name>
<email>yanquanmin1@huawei.com</email>
</author>
<published>2025-10-10T08:16:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a1f3058930745d2b938b6b4f5bd9630dc74b26b7'/>
<id>a1f3058930745d2b938b6b4f5bd9630dc74b26b7</id>
<content type='text'>
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:
 &lt;TASK&gt;
 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-&gt;modelist is freed, without setting the
corresponding fb_display[i]-&gt;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 &lt;yanquanmin1@huawei.com&gt;
Reviewed-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Cc: stable@vger.kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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:
 &lt;TASK&gt;
 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-&gt;modelist is freed, without setting the
corresponding fb_display[i]-&gt;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 &lt;yanquanmin1@huawei.com&gt;
Reviewed-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Cc: stable@vger.kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>fbdev: bitblit: bound-check glyph index in bit_putcs*</title>
<updated>2025-10-28T21:59:19+00:00</updated>
<author>
<name>Junjie Cao</name>
<email>junjie.cao@intel.com</email>
</author>
<published>2025-10-20T13:47:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=18c4ef4e765a798b47980555ed665d78b71aeadf'/>
<id>18c4ef4e765a798b47980555ed665d78b71aeadf</id>
<content type='text'>
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 &lt;junjie.cao@intel.com&gt;
Reviewed-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Cc: stable@vger.kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;junjie.cao@intel.com&gt;
Reviewed-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Cc: stable@vger.kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'fbdev-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev</title>
<updated>2025-10-10T16:36:23+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-10-10T16:36:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=06a88f47990974f1322c2bf2e8c5125f8a2f69fe'/>
<id>06a88f47990974f1322c2bf2e8c5125f8a2f69fe</id>
<content type='text'>
Pull fbdev updates from Helge Deller:
 "Beside the usual bunch of smaller bug fixes, the majority of changes
  were by Zsolt Kajtar to improve the s3fb driver.

  Bug fixes:
   - Bounds checking to fix vmalloc-out-of-bounds (Albin Babu Varghese)
   - Fix logic error in "offb" name match (Finn Thain)
   - simplefb: Fix use after free in (Janne Grunau)
   - s3fb: Various fixes and powersave improvements (Zsolt Kajtar)

  Enhancements &amp; code cleanups:
   - Various fixes in the documentation (Bagas Sanjaya)
   - Use string choices helpers (Chelsy Ratnawat)
   - xenfb: Use vmalloc_array to simplify code (Qianfeng Rong)
   - mb862xxfb: use signed type for error codes (Qianfeng Rong)
   - Make drivers depend on LCD_CLASS_DEVICE (Thomas Zimmermann)
   - radeonfb: Remove stale product link in Kconfig (Sukrut Heroorkar)"

* tag 'fbdev-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbdev: Fix logic error in "offb" name match
  fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds
  fbdev: Make drivers depend on LCD_CLASS_DEVICE
  fbdev: radeonfb: Remove stale product link in Kconfig
  Documentation: fb: Retitle driver docs
  Documentation: fb: ep93xx: Demote section headings
  Documentation: fb: Split toctree
  fbdev: simplefb: Fix use after free in simplefb_detach_genpds()
  fbdev: s3fb: Revert mclk stop in suspend
  fbdev: mb862xxfb: Use int type to store negative error codes
  fbdev: Use string choices helpers
  fbdev: core: Fix ubsan warning in pixel_to_pat
  fbdev: s3fb: Implement 1 and 2 BPP modes, improve 4 BPP
  fbdev: s3fb: Implement powersave for S3 FB
  fbdev: xenfb: Use vmalloc_array to simplify code
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull fbdev updates from Helge Deller:
 "Beside the usual bunch of smaller bug fixes, the majority of changes
  were by Zsolt Kajtar to improve the s3fb driver.

  Bug fixes:
   - Bounds checking to fix vmalloc-out-of-bounds (Albin Babu Varghese)
   - Fix logic error in "offb" name match (Finn Thain)
   - simplefb: Fix use after free in (Janne Grunau)
   - s3fb: Various fixes and powersave improvements (Zsolt Kajtar)

  Enhancements &amp; code cleanups:
   - Various fixes in the documentation (Bagas Sanjaya)
   - Use string choices helpers (Chelsy Ratnawat)
   - xenfb: Use vmalloc_array to simplify code (Qianfeng Rong)
   - mb862xxfb: use signed type for error codes (Qianfeng Rong)
   - Make drivers depend on LCD_CLASS_DEVICE (Thomas Zimmermann)
   - radeonfb: Remove stale product link in Kconfig (Sukrut Heroorkar)"

* tag 'fbdev-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbdev: Fix logic error in "offb" name match
  fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds
  fbdev: Make drivers depend on LCD_CLASS_DEVICE
  fbdev: radeonfb: Remove stale product link in Kconfig
  Documentation: fb: Retitle driver docs
  Documentation: fb: ep93xx: Demote section headings
  Documentation: fb: Split toctree
  fbdev: simplefb: Fix use after free in simplefb_detach_genpds()
  fbdev: s3fb: Revert mclk stop in suspend
  fbdev: mb862xxfb: Use int type to store negative error codes
  fbdev: Use string choices helpers
  fbdev: core: Fix ubsan warning in pixel_to_pat
  fbdev: s3fb: Implement 1 and 2 BPP modes, improve 4 BPP
  fbdev: s3fb: Implement powersave for S3 FB
  fbdev: xenfb: Use vmalloc_array to simplify code
</pre>
</div>
</content>
</entry>
</feed>
