486e666136
The use of stack Variable Length Arrays needs to be avoided, as they can be a vector for stack exhaustion, which can be both a runtime bug (kernel Oops) or a security flaw (overwriting memory beyond the stack). Also, in general, as code evolves it is easy to lose track of how big a VLA can get. Thus, we can end up having runtime failures that are hard to debug. As part of the directive[1] to remove all VLAs from the kernel, and build with -Wvla. Currently driver is using a VLA declared using the number of descriptors. This array is used to store integer values and is later used as an argument to `gpiod_set_array_value_cansleep()` This can be avoided by using `kmalloc_array()` to allocate memory for the array of integer values. Memory is free'd before return from function. >From the code it appears that it is safe to sleep so we can use GFP_KERNEL (based _cansleep() suffix of function `gpiod_set_array_value_cansleep()`. It can be expected that this patch will result in a small increase in overhead due to the use of `kmalloc_array()` [1] https://lkml.org/lkml/2018/3/7/621 Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.