This file is installed by the s390 CPU Measurement sampling facility device driver to export supported minimum and maximum sample buffer sizes. This file is read by lscpumf tool to display the details of the device driver capabilities. The lscpumf tool might be invoked by a non-root user. In this case it does not print anything because the file contents can not be read. Fix this by allowing read access for all users. Reading the file contents is ok, changing the file contents is left to the root user only. For further reference and details see: [1] https://github.com/ibm-s390-tools/s390-tools/issues/97 Fixes: 69f239ed335a ("s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur") Cc: <stable@vger.kernel.org> # 3.14 Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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.
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