e919a3f705
- Make buffer_percent read/write. The buffer_percent file is how users can state how long to block on the tracing buffer depending on how much is in the buffer. When it hits the "buffer_percent" it will wake the task waiting on the buffer. For some reason it was set to read-only. This was not noticed because testing was done as root without SELinux, but with SELinux it will prevent even root to write to it without having CAP_DAC_OVERRIDE. - The "touched_functions" was added this merge window, but one of the reasons for adding it was not implemented. That was to show what functions were not only touched, but had either a direct trampoline attached to it, or a kprobe or live kernel patching that can "hijack" the function to run a different function. The point is to know if there's functions in the kernel that may not be behaving as the kernel code shows. This can be used for debugging. TODO: Add this information to kernel oops too. -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCZFUcrxQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qgOoAP0U2R6+jvA2ehQFb0UTCH9wEu2uEELA g2CkdPNdn6wJjAD+O1+v5nVkqSpsArjHOhv5OGYrgh+VSXK3Z8EpQ9vUVgg= =nfoh -----END PGP SIGNATURE----- Merge tag 'trace-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull more tracing updates from Steven Rostedt: - Make buffer_percent read/write. The buffer_percent file is how users can state how long to block on the tracing buffer depending on how much is in the buffer. When it hits the "buffer_percent" it will wake the task waiting on the buffer. For some reason it was set to read-only. This was not noticed because testing was done as root without SELinux, but with SELinux it will prevent even root to write to it without having CAP_DAC_OVERRIDE. - The "touched_functions" was added this merge window, but one of the reasons for adding it was not implemented. That was to show what functions were not only touched, but had either a direct trampoline attached to it, or a kprobe or live kernel patching that can "hijack" the function to run a different function. The point is to know if there's functions in the kernel that may not be behaving as the kernel code shows. This can be used for debugging. TODO: Add this information to kernel oops too. * tag 'trace-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ftrace: Add MODIFIED flag to show if IPMODIFY or direct was attached tracing: Fix permissions for the buffer_percent file
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.