Re: [RFC][PATCH] debugfs: Fix corrupted loop in debugfs_remove_recursive

[Steven Rostedt <rostedt@goodmis.org>]

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On Mon, 9 Jun 2014 14:06:07 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> [ I'm currently running my tests on it now, and so far, after a few
>  hours it has yet to blow up. I'll run it for 24 hours which it never
>  succeeded in the past. ]

I ran with this patch on three boxes all night, one for 24 hours. No
problems. I stopped the tests, removed the patch, ran the test on the
same boxes and they all crashed within an hour.

This patch definitely fixes the bug.

The test I ran was:

while :; do
 ./ftrace-test-mkinstances || break
 ./ftrace-test-mkinstances-2 || break
done

Note, the tests expect debugfs to be mounted at /debug.

-- Steve

[-- Attachment #2: ftrace-test-mkinstances --]
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#!/bin/bash

if [ ! -d /debug/tracing/instances ]; then
	echo "No instances directory"
	exit 0
fi

cd /debug/tracing/instances

mkdir x
rmdir x
result=$?

if [ $result -ne 0 ]; then
	echo "instance rmdir not supported, skipping this test"
	exit 0
fi

instance_slam() {
	while :; do
		mkdir x
		mkdir y
		mkdir z
		rmdir x
		rmdir y
		rmdir z
	done 2>/dev/null
}

instance_slam &
x=`jobs -l`
p1=`echo $x | cut -d' ' -f2`
echo $p1

instance_slam &
x=`jobs -l | tail -1`
p2=`echo $x | cut -d' ' -f2`
echo $p2

instance_slam &
x=`jobs -l | tail -1`
p3=`echo $x | cut -d' ' -f2`
echo $p3

instance_slam &
x=`jobs -l | tail -1`
p4=`echo $x | cut -d' ' -f2`
echo $p4

instance_slam &
x=`jobs -l | tail -1`
p5=`echo $x | cut -d' ' -f2`
echo $p5

for i in `seq 10`; do
	ls
	sleep 1
done
kill -1 $p1 
kill -1 $p2
kill -1 $p3
kill -1 $p4
kill -1 $p5

echo "Wait for processes to finish"
wait $p1 $p2 $p3 $p4 $p5
echo "all processes finished, wait for cleanup"
sleep 2

mkdir x y z
ls x y z
rmdir x y z
for d in x y z; do
	if [ -d $d ]; then
		echo $d still exists
		exit -1
	fi
done
echo SUCCESS
exit 0

[-- Attachment #3: ftrace-test-mkinstances-2 --]
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#!/bin/bash

if [ ! -d /debug/tracing/instances ]; then
	echo "No instances directory"
	exit 0
fi

cd /debug/tracing/instances

instance_slam() {
	while :; do
		mkdir foo &> /dev/null
		rmdir foo &> /dev/null
	done
}

instance_read() {
	while :; do
		cat foo/trace &> /dev/null
	done
}

instance_set() {
	while :; do
		echo 1 > foo/events/sched/sched_switch
	done 2> /dev/null
}

instance_slam &
x=`jobs -l`
p1=`echo $x | cut -d' ' -f2`
echo $p1

instance_set &
x=`jobs -l | tail -1`
p2=`echo $x | cut -d' ' -f2`
echo $p2

sleep 10

kill -1 $p1 
kill -1 $p2

echo "Wait for processes to finish"
wait $p1 $p2
echo "all processes finished, wait for cleanup"
sleep 2

mkdir foo
ls foo
rmdir foo
if [ -d foo ]; then
	echo foo still exists
	exit -1
fi
echo SUCCESS
exit 0