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[ Upstream commit2bc6262c61] All of the CPPC sysfs show functions are called via indirect call in kobj_attr_show(), where they should be of type ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr, char *buf); because that is the type of the ->show() member in 'struct kobj_attribute' but they are actually of type ssize_t (*show)(struct kobject *kobj, struct attribute *attr, char *buf); because of the ->show() member in 'struct cppc_attr', resulting in a Control Flow Integrity violation [1]. $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/highest_perf 3400 $ dmesg | grep "CFI failure" [ 175.970559] CFI failure (target: show_highest_perf+0x0/0x8): As far as I can tell, the only difference between 'struct cppc_attr' and 'struct kobj_attribute' aside from the type of the attr parameter is the type of the count parameter in the ->store() member (ssize_t vs. size_t), which does not actually matter because all of these nodes are read-only. Eliminate 'struct cppc_attr' in favor of 'struct kobj_attribute' to fix the violation. [1]: https://lore.kernel.org/r/20210401233216.2540591-1-samitolvanen@google.com/ Fixes:158c998ea4("ACPI / CPPC: add sysfs support to compute delivered performance") Link: https://github.com/ClangBuiltLinux/linux/issues/1343 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.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.