f0a06203f2
[ Upstream commit 47e8b73bc35d7c54642f78e498697692f6358996 ] When the driver calls cx23885_risc_buffer() to prepare the buffer, the function call dma_alloc_coherent may fail, resulting in a empty buffer risc->cpu. Later when we free the buffer or access the buffer, null ptr deref is triggered. This bug is similar to the following one: https://git.linuxtv.org/media_stage.git/commit/?id=2b064d91440b33fba5b452f2d1b31f13ae911d71. We believe the bug can be also dynamically triggered from user side. Similarly, we fix this by checking the return value of cx23885_risc_buffer() and the value of risc->cpu before buffer free. Signed-off-by: harperchen <harperchen1110@gmail.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> 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.