diff options
Diffstat (limited to '')
| -rwxr-xr-x | scripts/tracing/draw_functrace.py | 129 | ||||
| -rwxr-xr-x | scripts/tracing/ftrace-bisect.sh | 134 |
2 files changed, 263 insertions, 0 deletions
diff --git a/scripts/tracing/draw_functrace.py b/scripts/tracing/draw_functrace.py new file mode 100755 index 000000000..438516bdf --- /dev/null +++ b/scripts/tracing/draw_functrace.py @@ -0,0 +1,129 @@ +#!/usr/bin/env python +# SPDX-License-Identifier: GPL-2.0-only + +""" +Copyright 2008 (c) Frederic Weisbecker <fweisbec@gmail.com> + +This script parses a trace provided by the function tracer in +kernel/trace/trace_functions.c +The resulted trace is processed into a tree to produce a more human +view of the call stack by drawing textual but hierarchical tree of +calls. Only the functions's names and the call time are provided. + +Usage: + Be sure that you have CONFIG_FUNCTION_TRACER + # mount -t debugfs nodev /sys/kernel/debug + # echo function > /sys/kernel/debug/tracing/current_tracer + $ cat /sys/kernel/debug/tracing/trace_pipe > ~/raw_trace_func + Wait some times but not too much, the script is a bit slow. + Break the pipe (Ctrl + Z) + $ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace + Then you have your drawn trace in draw_functrace +""" + + +import sys, re + +class CallTree: + """ This class provides a tree representation of the functions + call stack. If a function has no parent in the kernel (interrupt, + syscall, kernel thread...) then it is attached to a virtual parent + called ROOT. + """ + ROOT = None + + def __init__(self, func, time = None, parent = None): + self._func = func + self._time = time + if parent is None: + self._parent = CallTree.ROOT + else: + self._parent = parent + self._children = [] + + def calls(self, func, calltime): + """ If a function calls another one, call this method to insert it + into the tree at the appropriate place. + @return: A reference to the newly created child node. + """ + child = CallTree(func, calltime, self) + self._children.append(child) + return child + + def getParent(self, func): + """ Retrieve the last parent of the current node that + has the name given by func. If this function is not + on a parent, then create it as new child of root + @return: A reference to the parent. + """ + tree = self + while tree != CallTree.ROOT and tree._func != func: + tree = tree._parent + if tree == CallTree.ROOT: + child = CallTree.ROOT.calls(func, None) + return child + return tree + + def __repr__(self): + return self.__toString("", True) + + def __toString(self, branch, lastChild): + if self._time is not None: + s = "%s----%s (%s)\n" % (branch, self._func, self._time) + else: + s = "%s----%s\n" % (branch, self._func) + + i = 0 + if lastChild: + branch = branch[:-1] + " " + while i < len(self._children): + if i != len(self._children) - 1: + s += "%s" % self._children[i].__toString(branch +\ + " |", False) + else: + s += "%s" % self._children[i].__toString(branch +\ + " |", True) + i += 1 + return s + +class BrokenLineException(Exception): + """If the last line is not complete because of the pipe breakage, + we want to stop the processing and ignore this line. + """ + pass + +class CommentLineException(Exception): + """ If the line is a comment (as in the beginning of the trace file), + just ignore it. + """ + pass + + +def parseLine(line): + line = line.strip() + if line.startswith("#"): + raise CommentLineException + m = re.match("[^]]+?\\] +([a-z.]+) +([0-9.]+): (\\w+) <-(\\w+)", line) + if m is None: + raise BrokenLineException + return (m.group(2), m.group(3), m.group(4)) + + +def main(): + CallTree.ROOT = CallTree("Root (Nowhere)", None, None) + tree = CallTree.ROOT + + for line in sys.stdin: + try: + calltime, callee, caller = parseLine(line) + except BrokenLineException: + break + except CommentLineException: + continue + tree = tree.getParent(caller) + tree = tree.calls(callee, calltime) + + print(CallTree.ROOT) + +if __name__ == "__main__": + main() diff --git a/scripts/tracing/ftrace-bisect.sh b/scripts/tracing/ftrace-bisect.sh new file mode 100755 index 000000000..bb4f59262 --- /dev/null +++ b/scripts/tracing/ftrace-bisect.sh @@ -0,0 +1,134 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Here's how to use this: +# +# This script is used to help find functions that are being traced by function +# tracer or function graph tracing that causes the machine to reboot, hang, or +# crash. Here's the steps to take. +# +# First, determine if function tracing is working with a single function: +# +# (note, if this is a problem with function_graph tracing, then simply +# replace "function" with "function_graph" in the following steps). +# +# # cd /sys/kernel/tracing +# # echo schedule > set_ftrace_filter +# # echo function > current_tracer +# +# If this works, then we know that something is being traced that shouldn't be. +# +# # echo nop > current_tracer +# +# Starting with v5.1 this can be done with numbers, making it much faster: +# +# The old (slow) way, for kernels before v5.1. +# +# [old-way] # cat available_filter_functions > ~/full-file +# +# [old-way] *** Note *** this process will take several minutes to update the +# [old-way] filters. Setting multiple functions is an O(n^2) operation, and we +# [old-way] are dealing with thousands of functions. So go have coffee, talk +# [old-way] with your coworkers, read facebook. And eventually, this operation +# [old-way] will end. +# +# The new way (using numbers) is an O(n) operation, and usually takes less than a second. +# +# seq `wc -l available_filter_functions | cut -d' ' -f1` > ~/full-file +# +# This will create a sequence of numbers that match the functions in +# available_filter_functions, and when echoing in a number into the +# set_ftrace_filter file, it will enable the corresponding function in +# O(1) time. Making enabling all functions O(n) where n is the number of +# functions to enable. +# +# For either the new or old way, the rest of the operations remain the same. +# +# # ftrace-bisect ~/full-file ~/test-file ~/non-test-file +# # cat ~/test-file > set_ftrace_filter +# +# # echo function > current_tracer +# +# If it crashes, we know that ~/test-file has a bad function. +# +# Reboot back to test kernel. +# +# # cd /sys/kernel/tracing +# # mv ~/test-file ~/full-file +# +# If it didn't crash. +# +# # echo nop > current_tracer +# # mv ~/non-test-file ~/full-file +# +# Get rid of the other test file from previous run (or save them off somewhere). +# # rm -f ~/test-file ~/non-test-file +# +# And start again: +# +# # ftrace-bisect ~/full-file ~/test-file ~/non-test-file +# +# The good thing is, because this cuts the number of functions in ~/test-file +# by half, the cat of it into set_ftrace_filter takes half as long each +# iteration, so don't talk so much at the water cooler the second time. +# +# Eventually, if you did this correctly, you will get down to the problem +# function, and all we need to do is to notrace it. +# +# The way to figure out if the problem function is bad, just do: +# +# # echo <problem-function> > set_ftrace_notrace +# # echo > set_ftrace_filter +# # echo function > current_tracer +# +# And if it doesn't crash, we are done. +# +# If it does crash, do this again (there's more than one problem function) +# but you need to echo the problem function(s) into set_ftrace_notrace before +# enabling function tracing in the above steps. Or if you can compile the +# kernel, annotate the problem functions with "notrace" and start again. +# + + +if [ $# -ne 3 ]; then + echo 'usage: ftrace-bisect full-file test-file non-test-file' + exit +fi + +full=$1 +test=$2 +nontest=$3 + +x=`cat $full | wc -l` +if [ $x -eq 1 ]; then + echo "There's only one function left, must be the bad one" + cat $full + exit 0 +fi + +let x=$x/2 +let y=$x+1 + +if [ ! -f $full ]; then + echo "$full does not exist" + exit 1 +fi + +if [ -f $test ]; then + echo -n "$test exists, delete it? [y/N]" + read a + if [ "$a" != "y" -a "$a" != "Y" ]; then + exit 1 + fi +fi + +if [ -f $nontest ]; then + echo -n "$nontest exists, delete it? [y/N]" + read a + if [ "$a" != "y" -a "$a" != "Y" ]; then + exit 1 + fi +fi + +sed -ne "1,${x}p" $full > $test +sed -ne "$y,\$p" $full > $nontest |