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45dd9b0666
Doing an audit of trace events, I discovered two trace events in the xen
subsystem that use a hack to create zero data size trace events. This is not
what trace events are for. Trace events add memory footprint overhead, and
if all you need to do is see if a function is hit or not, simply make that
function noinline and use function tracer filtering.
Worse yet, the hack used was:
__array(char, x, 0)
Which creates a static string of zero in length. There's assumptions about
such constructs in ftrace that this is a dynamic string that is nul
terminated. This is not the case with these tracepoints and can cause
problems in various parts of ftrace.
Nuke the trace events!
Link: http://lkml.kernel.org/r/20180509144605.5a220327@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 95a7d76897 ("xen/mmu: Use Xen specific TLB flush instead of the generic one.")
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.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.
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.