[for-linus][PATCH 0/2] tracing: Minor updates for 6.4

From: Steven Rostedt
Date: Wed May 03 2023 - 19:15:46 EST



Minor updates:

- 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 can a different function. The point is to know if there's functions
in the kernel that may not be behaving as kernel code shows. This can
be used for debugging. TODO: Add this information to kernel oops too.

Ondrej Mosnacek (1):
tracing: Fix permissions for the buffer_percent file

Steven Rostedt (Google) (1):
ftrace: Add MODIFIED flag to show if IPMODIFY or direct was attached

----
Documentation/trace/ftrace.rst | 25 +++++++++++++++++++++++++
include/linux/ftrace.h | 4 +++-
kernel/trace/ftrace.c | 12 +++++++++---
kernel/trace/trace.c | 2 +-
4 files changed, 38 insertions(+), 5 deletions(-)