I got a null-ptr-deref report when closing a DRM file descriptor:

WARNING: drivers/gpu/drm/drm_atomic.c:2031 at
__drm_atomic_helper_set_config+0x18e/0x1b0 [drm]

Call Trace:
drm_client_modeset_commit_atomic+0x16b/0x220 [drm]
drm_client_modeset_commit_locked+0x56/0x160 [drm]
drm_client_modeset_commit+0x21/0x40 [drm]
__drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x7b/0x80
drm_fbdev_client_restore+0xe/0x20 [drm_client_lib]
drm_client_dev_restore+0x9f/0xc0 [drm]
drm_release+0xc5/0xe0 [drm]

The warning is followed by a NULL pointer dereference:

BUG: kernel NULL pointer dereference, address: 0000000000000008

RIP:
__drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x41/0x80
[drm_kms_helper]

Call Trace:
drm_fbdev_client_restore+0xe/0x20 [drm_client_lib]
drm_client_dev_restore+0x9f/0xc0 [drm]
drm_release+0xc5/0xe0 [drm]
__fput+0xdc/0x2b0
__x64_sys_close+0x39/0x80
do_syscall_64+0x8d/0x460
entry_SYSCALL_64_after_hwframe+0x76/0x7e

drm_client_register() adds the DRM client to the device client list
before invoking the initial hotplug callback. If the hotplug callback
fails, the client remains registered.

For the fbdev client, a failure during drm_fb_helper_initial_config()
causes the partially initialized fbdev helper to be cleaned up.
drm_fb_helper_fini() releases fb_helper->info and leaves it NULL.

The fbdev client therefore remains registered even though there is no
fully initialized framebuffer device.

Later, when userspace closes the DRM file descriptor, drm_release()
can invoke the restore callbacks of registered DRM clients:

drm_release()
drm_client_dev_restore()
drm_fbdev_client_restore()
drm_fb_helper_restore_fbdev_mode_unlocked()

drm_fbdev_client_restore() currently restores the fbdev state
unconditionally. For a partially initialized fbdev client this can
submit an incomplete modeset state and subsequently access fbdev
state which has not been initialized, resulting in the warning and
NULL pointer dereference above.

drm_fbdev_client_unregister() already uses fb_helper->info to
distinguish a fully probed framebuffer device from a partially
initialized client.

Use the same condition in drm_fbdev_client_restore() and skip restore
if no framebuffer device has been successfully initialized.

Signed-off-by: shechenglong <shechenglong@xfusion.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 5d08c44e47b9 ("drm/fbdev: Add memory-agnostic fbdev client")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: <stable@vger.kernel.org> # v6.13+
Link: https://patch.msgid.link/20260907035147.1339-1-shechenglong@xfusion.com

Linux 7.2

There was a lot of conflicts this round between fixes and next,
and I'd like to get the merge resolutions that we have in drm-tip.

Signed-off-by: Dave Airlie <airlied@redhat.com>

When scale is large enough that scaled_font exceeds the display
dimensions, rows or columns become 0. A columns value of 0 causes
an infinite loop in drm_log_draw_kmsg_record() because the loop
never decrements len.

Check for zero rows/columns in drm_log_setup_modeset() and return
an error, cleaning up the already allocated buffer to avoid a leak.

Fixes: 8a4b913df427 ("drm/log: Add integer scaling support")
Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260729084815.692944-1-oushixiong1025@163.com
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>

drm_log_draw_kmsg_record() accesses s[len - 1] to strip the trailing
newline, but len is unsigned int. If len is 0, the subtraction wraps
to UINT_MAX, causing an out-of-bounds read.

Add an early return when len is 0.

Fixes: 25e2c2a3eff5 ("drm/log: Color the timestamp, to improve readability")
Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260729084520.688087-1-oushixiong1025@163.com
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>

The scale module parameter can be set to 0 via kernel command line.
When scale is 0, scaled_font_h and scaled_font_w become 0, causing
a division by zero in the rows/columns calculation.

Since the scale module parameter is read-only (0444 permissions), it
cannot be changed at runtime via sysfs. Clamp it to 1 once in
drm_log_register().

Fixes: 8a4b913df427 ("drm/log: Add integer scaling support")
Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260730014440.66323-1-oushixiong1025@163.com
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>

Look up glyph shapes with font_data_glyph_buf(). Handle non-existing
glyphs gracefully. Enable extended ASCII by casting to unsigned char.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260529140759.529929-3-tzimmermann@suse.de

This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>

Use drm_draw_can_convert_from_xrgb8888() instead of
drm_draw_color_from_xrgb8888() while searching for a usable color
format. This avoids a WARN in case the first format is not usable.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Francesco Valla <francesco@valla.it>
Link: https://patch.msgid.link/20251217-drm_draw_conv_check-v3-2-15b6f8bc1cbc@valla.it
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>

Extra drm-misc-next for v6.19-rc1:

UAPI Changes:
- Add support for drm colorop pipeline.
- Add COLOR PIPELINE plane property.
- Add DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE.

Cross-subsystem Changes:
- Attempt to use higher order mappings in system heap allocator.
- Always taint kernel with sw-sync.

Core Changes:
- Small fixes to drm/gem.
- Support emergency restore to drm-client.
- Allocate and release fb_info in single place.
- Rework ttm pipelined eviction fence handling.

Driver Changes:
- Support the drm color pipeline in vkms, amdgfx.
- Add NVJPG driver for tegra.
- Assorted small fixes and updates to rockchip, bridge/dw-hdmi-qp,
  panthor.
- Add ASL CS5263 DP-to-HDMI simple bridge.
- Add and improve support for G LD070WX3-SL01 MIPI DSI, Samsung LTL106AL0,
  Samsung LTL106AL01, Raystar RFF500F-AWH-DNN, Winstar WF70A8SYJHLNGA,
  Wanchanglong w552946aaa, Samsung SOFEF00, Lenovo X13s panel.
- Add support for it66122 to it66121.
- Support mali-G1 gpu in panthor.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patch.msgid.link/aa5cbd50-7676-4a59-bbed-e8428af86804@linux.intel.com