[PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Swapnil Sapkal]

In cpufreq basic selftests, one of the testcases is to read all cpufreq
sysfs files and print the values. This testcase assumes all the cpufreq
sysfs files have read permissions. However certain cpufreq sysfs files
(eg. stats/reset) are write only files and this testcase errors out
when it is not able to read the file.
Similarily, there is one more testcase which reads the cpufreq sysfs
file data and write it back to same file. This testcase also errors out
for sysfs files without read permission.
Fix these testcases by adding proper read permission checks.

Reported-by: Narasimhan V <narasimhan.v@amd.com>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
---
 tools/testing/selftests/cpufreq/cpufreq.sh | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/cpufreq/cpufreq.sh b/tools/testing/selftests/cpufreq/cpufreq.sh
index e350c521b467..3484fa34e8d8 100755
--- a/tools/testing/selftests/cpufreq/cpufreq.sh
+++ b/tools/testing/selftests/cpufreq/cpufreq.sh
@@ -52,7 +52,14 @@ read_cpufreq_files_in_dir()
 	for file in $files; do
 		if [ -f $1/$file ]; then
 			printf "$file:"
-			cat $1/$file
+			#file is readable ?
+			local rfile=$(ls -l $1/$file | awk '$1 ~ /^.*r.*/ { print $NF; }')
+
+			if [ ! -z $rfile ]; then
+				cat $1/$file
+			else
+				printf "$file is not readable\n"
+			fi
 		else
 			printf "\n"
 			read_cpufreq_files_in_dir "$1/$file"
@@ -83,10 +90,10 @@ update_cpufreq_files_in_dir()
 
 	for file in $files; do
 		if [ -f $1/$file ]; then
-			# file is writable ?
-			local wfile=$(ls -l $1/$file | awk '$1 ~ /^.*w.*/ { print $NF; }')
+			# file is readable and writable ?
+			local rwfile=$(ls -l $1/$file | awk '$1 ~ /^.*rw.*/ { print $NF; }')
 
-			if [ ! -z $wfile ]; then
+			if [ ! -z $rwfile ]; then
 				# scaling_setspeed is a special file and we
 				# should skip updating it
 				if [ $file != "scaling_setspeed" ]; then
-- 
2.43.0

Re: [PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Viresh Kumar]

On 30-04-25, 17:14, Swapnil Sapkal wrote:
> In cpufreq basic selftests, one of the testcases is to read all cpufreq
> sysfs files and print the values. This testcase assumes all the cpufreq
> sysfs files have read permissions. However certain cpufreq sysfs files
> (eg. stats/reset) are write only files and this testcase errors out
> when it is not able to read the file.
> Similarily, there is one more testcase which reads the cpufreq sysfs
> file data and write it back to same file. This testcase also errors out
> for sysfs files without read permission.
> Fix these testcases by adding proper read permission checks.
> 
> Reported-by: Narasimhan V <narasimhan.v@amd.com>
> Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
> ---
>  tools/testing/selftests/cpufreq/cpufreq.sh | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/selftests/cpufreq/cpufreq.sh b/tools/testing/selftests/cpufreq/cpufreq.sh
> index e350c521b467..3484fa34e8d8 100755
> --- a/tools/testing/selftests/cpufreq/cpufreq.sh
> +++ b/tools/testing/selftests/cpufreq/cpufreq.sh
> @@ -52,7 +52,14 @@ read_cpufreq_files_in_dir()
>  	for file in $files; do
>  		if [ -f $1/$file ]; then
>  			printf "$file:"
> -			cat $1/$file
> +			#file is readable ?
> +			local rfile=$(ls -l $1/$file | awk '$1 ~ /^.*r.*/ { print $NF; }')
> +
> +			if [ ! -z $rfile ]; then
> +				cat $1/$file
> +			else
> +				printf "$file is not readable\n"
> +			fi

What about:

if [ -r $1/$file ]; then
    cat $1/$file
else
    printf "$file is not readable\n"
fi


-- 
viresh

Re: [PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Sapkal, Swapnil]

Hi Viresh,

On 5/19/2025 1:28 PM, Viresh Kumar wrote:
> On 30-04-25, 17:14, Swapnil Sapkal wrote:
>> In cpufreq basic selftests, one of the testcases is to read all cpufreq
>> sysfs files and print the values. This testcase assumes all the cpufreq
>> sysfs files have read permissions. However certain cpufreq sysfs files
>> (eg. stats/reset) are write only files and this testcase errors out
>> when it is not able to read the file.
>> Similarily, there is one more testcase which reads the cpufreq sysfs
>> file data and write it back to same file. This testcase also errors out
>> for sysfs files without read permission.
>> Fix these testcases by adding proper read permission checks.
>>
>> Reported-by: Narasimhan V <narasimhan.v@amd.com>
>> Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
>> ---
>>   tools/testing/selftests/cpufreq/cpufreq.sh | 15 +++++++++++----
>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/testing/selftests/cpufreq/cpufreq.sh b/tools/testing/selftests/cpufreq/cpufreq.sh
>> index e350c521b467..3484fa34e8d8 100755
>> --- a/tools/testing/selftests/cpufreq/cpufreq.sh
>> +++ b/tools/testing/selftests/cpufreq/cpufreq.sh
>> @@ -52,7 +52,14 @@ read_cpufreq_files_in_dir()
>>   	for file in $files; do
>>   		if [ -f $1/$file ]; then
>>   			printf "$file:"
>> -			cat $1/$file
>> +			#file is readable ?
>> +			local rfile=$(ls -l $1/$file | awk '$1 ~ /^.*r.*/ { print $NF; }')
>> +
>> +			if [ ! -z $rfile ]; then
>> +				cat $1/$file
>> +			else
>> +				printf "$file is not readable\n"
>> +			fi
> 
> What about:
> 
> if [ -r $1/$file ]; then
>      cat $1/$file
> else
>      printf "$file is not readable\n"
> fi
> 
> 

Initially I tried the same, but it does not work properly with the root user.

--
Thanks and Regards,
Swapnil

Re: [PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Viresh Kumar]

On 22-05-25, 14:07, Sapkal, Swapnil wrote:
> Initially I tried the same, but it does not work properly with the root user.

Hmm,

Tried chatgpt now and it says this should work:

if ! cat "$1/$file" 2>/dev/null; then
    printf "$file is not readable\n"
fi

- This attempts to read the file.
- If it fails, the cat command returns non-zero, and you print a message.
- 2>/dev/null suppresses error messages (Permission denied, etc.)
- This works reliably for both root and non-root users, because it actually tests the read action, not just permission bits.

-- 
viresh

Re: [PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Shuah Khan]

On 5/19/25 01:58, Viresh Kumar wrote:
> On 30-04-25, 17:14, Swapnil Sapkal wrote:
>> In cpufreq basic selftests, one of the testcases is to read all cpufreq
>> sysfs files and print the values. This testcase assumes all the cpufreq
>> sysfs files have read permissions. However certain cpufreq sysfs files
>> (eg. stats/reset) are write only files and this testcase errors out
>> when it is not able to read the file.
>> Similarily, there is one more testcase which reads the cpufreq sysfs
>> file data and write it back to same file. This testcase also errors out
>> for sysfs files without read permission.
>> Fix these testcases by adding proper read permission checks.

Can you share how you ran the test?

>>
>> Reported-by: Narasimhan V <narasimhan.v@amd.com>
>> Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
>> ---
>>   tools/testing/selftests/cpufreq/cpufreq.sh | 15 +++++++++++----
>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/testing/selftests/cpufreq/cpufreq.sh b/tools/testing/selftests/cpufreq/cpufreq.sh
>> index e350c521b467..3484fa34e8d8 100755
>> --- a/tools/testing/selftests/cpufreq/cpufreq.sh
>> +++ b/tools/testing/selftests/cpufreq/cpufreq.sh
>> @@ -52,7 +52,14 @@ read_cpufreq_files_in_dir()
>>   	for file in $files; do
>>   		if [ -f $1/$file ]; then
>>   			printf "$file:"
>> -			cat $1/$file
>> +			#file is readable ?
>> +			local rfile=$(ls -l $1/$file | awk '$1 ~ /^.*r.*/ { print $NF; }')
>> +
>> +			if [ ! -z $rfile ]; then
>> +				cat $1/$file
>> +			else
>> +				printf "$file is not readable\n"
>> +			fi
> 
> What about:
> 
> if [ -r $1/$file ]; then
>      cat $1/$file
> else
>      printf "$file is not readable\n"
> fi
> 
> 

thanks,
-- Shuah

Re: [PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Sapkal, Swapnil]

Hi Shuah,

On 5/22/2025 8:47 PM, Shuah Khan wrote:
> On 5/19/25 01:58, Viresh Kumar wrote:
>> On 30-04-25, 17:14, Swapnil Sapkal wrote:
>>> In cpufreq basic selftests, one of the testcases is to read all cpufreq
>>> sysfs files and print the values. This testcase assumes all the cpufreq
>>> sysfs files have read permissions. However certain cpufreq sysfs files
>>> (eg. stats/reset) are write only files and this testcase errors out
>>> when it is not able to read the file.
>>> Similarily, there is one more testcase which reads the cpufreq sysfs
>>> file data and write it back to same file. This testcase also errors out
>>> for sysfs files without read permission.
>>> Fix these testcases by adding proper read permission checks.
> 
> Can you share how you ran the test?
> 

I ran the basic tests with the following command:

./main.sh -t basic

>>>
>>> Reported-by: Narasimhan V <narasimhan.v@amd.com>
>>> Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
>>> ---
>>>   tools/testing/selftests/cpufreq/cpufreq.sh | 15 +++++++++++----
>>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tools/testing/selftests/cpufreq/cpufreq.sh b/tools/testing/selftests/cpufreq/cpufreq.sh
>>> index e350c521b467..3484fa34e8d8 100755
>>> --- a/tools/testing/selftests/cpufreq/cpufreq.sh
>>> +++ b/tools/testing/selftests/cpufreq/cpufreq.sh
>>> @@ -52,7 +52,14 @@ read_cpufreq_files_in_dir()
>>>       for file in $files; do
>>>           if [ -f $1/$file ]; then
>>>               printf "$file:"
>>> -            cat $1/$file
>>> +            #file is readable ?
>>> +            local rfile=$(ls -l $1/$file | awk '$1 ~ /^.*r.*/ { print $NF; }')
>>> +
>>> +            if [ ! -z $rfile ]; then
>>> +                cat $1/$file
>>> +            else
>>> +                printf "$file is not readable\n"
>>> +            fi
>>
>> What about:
>>
>> if [ -r $1/$file ]; then
>>      cat $1/$file
>> else
>>      printf "$file is not readable\n"
>> fi
>>
>>
> 
> thanks,
> -- Shuah
--
Thanks and Regards,
Swapnil

Re: [PATCH] selftests/cpufreq: Fix cpufreq basic read and update testcases

[Sapkal, Swapnil]

Hi Viresh,

On 5/22/2025 3:15 PM, Viresh Kumar wrote:
> On 22-05-25, 14:07, Sapkal, Swapnil wrote:
>> Initially I tried the same, but it does not work properly with the root user.
> 
> Hmm,
> 
> Tried chatgpt now and it says this should work:
> 
> if ! cat "$1/$file" 2>/dev/null; then
>      printf "$file is not readable\n"
> fi
> 
> - This attempts to read the file.
> - If it fails, the cat command returns non-zero, and you print a message.
> - 2>/dev/null suppresses error messages (Permission denied, etc.)
> - This works reliably for both root and non-root users, because it actually tests the read action, not just permission bits.
> 

This looks clean. I will send v2 with this change.

--
Thanks and Regards,
Swapnil