drm/omap: Fix possible NULL dereference

Browse source

[ Upstream commit a88fee2d67 ]

smatch reports:

drivers/gpu/drm/omapdrm/dss/base.c:176 omapdss_device_disconnect() error: we previously assumed 'src' could be null (see line 169)

This code is mostly from a time when omapdrm had its own display device
model. I can't honestly remember the details, and I don't think it's
worth digging in deeply into that for a legacy driver.

However, it looks like we only call omapdss_device_disconnect() and
omapdss_device_connect() with NULL as the src parameter. We can thus
drop the src parameter from both functions, and fix the smatch warning.

I don't think omapdss_device_disconnect() ever gets NULL for the dst
parameter (if it did, we'd crash soon after returning from the
function), but I have kept the !dst check, just in case, but I added a
WARN_ON() there.

Also, if the dst parameter can be NULL, we can't always get the struct
dss_device pointer from dst->dss (which is only used for a debug print).
To make sure we can't hit that issue, do it similarly to the
omapdss_device_connect() function: add 'struct dss_device *dss' as the
first parameter, so that we always have it regardless of the dst.

Fixes: 79107f274b ("drm/omap: Add support for drm_bridge")
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240806-omapdrm-misc-fixes-v1-1-15d31aea0831@ideasonboard.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Tomi Valkeinen 2024-08-06 16:50:27 +03:00 • committed by Greg Kroah-Hartman

parent bc981179ab

commit dfb49eabed

3 changed files with 9 additions and 23 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

25

drivers/gpu/drm/omapdrm/dss/base.c

View file

3

drivers/gpu/drm/omapdrm/dss/omapdss.h

View file

4

drivers/gpu/drm/omapdrm/omap_drv.c

View file