bc79cb9fb0
[ Upstream commit cf53db768a8790fdaae2fa3a81322b080285f7e5 ]
A problem about modprobe vc4 failed is triggered with the following log
given:
[ 420.327987] Error: Driver 'vc4_hvs' is already registered, aborting...
[ 420.333904] failed to register platform driver vc4_hvs_driver [vc4]: -16
modprobe: ERROR: could not insert 'vc4': Device or resource busy
The reason is that vc4_drm_register() returns platform_driver_register()
directly without checking its return value, if platform_driver_register()
fails, it returns without unregistering all the vc4 drivers, resulting the
vc4 can never be installed later.
A simple call graph is shown as below:
vc4_drm_register()
platform_register_drivers() # all vc4 drivers are registered
platform_driver_register()
driver_register()
bus_add_driver()
priv = kzalloc(...) # OOM happened
# return without unregister drivers
Fixing this problem by checking the return value of
platform_driver_register() and do platform_unregister_drivers() if
error happened.
Fixes: c8b75bca92cb ("drm/vc4: Add KMS support for Raspberry Pi.")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20221103014705.109322-1-yuancan@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.