[PATCH] kernel-chktaint: add reporting for tainted modules

[PATCH] kernel-chktaint: add reporting for tainted modules

[Randy Dunlap]

Check all loaded modules and report any that have their 'taint'
flags set along with a count of all tainted modules.
The tainted module output format is:
<module_name>: taint=<flags>

Example output:

Kernel is "tainted" for the following reasons:
 * externally-built ('out-of-tree') module was loaded  (#12)
 * unsigned module was loaded (#13)
Raw taint value as int/string: 12288/'G           OE      '

Modules tainted: count=1
dump_test: taint=OE


Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
---
Cc: Thorsten Leemhuis <linux@leemhuis.info>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
---
 tools/debugging/kernel-chktaint |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

--- linux-next-20251027.orig/tools/debugging/kernel-chktaint
+++ linux-next-20251027/tools/debugging/kernel-chktaint
@@ -211,9 +211,24 @@ else
 	addout "J"
 	echo " * fwctl's mutating debug interface was used (#19)"
 fi
+echo "Raw taint value as int/string: $taint/'$out'"
+
+# report on any tainted loadable modules
+[ -r /sys/module/ ] && cnt=`grep [A-Z] /sys/module/*/taint | wc -l` || cnt=0
 
+if [ $cnt -ne 0 ]; then
+	echo
+	echo "Modules tainted: count=$cnt"
+	for dir in `ls /sys/module` ; do
+		if [ -r /sys/module/$dir/taint ]; then
+			modtnt=`cat /sys/module/$dir/taint`
+			[ "$modtnt" = "" ] || echo "$dir: taint=$modtnt"
+		fi
+	done
+fi
+
+echo
 echo "For a more detailed explanation of the various taint flags see"
 echo " Documentation/admin-guide/tainted-kernels.rst in the Linux kernel sources"
 echo " or https://kernel.org/doc/html/latest/admin-guide/tainted-kernels.html"
-echo "Raw taint value as int/string: $taint/'$out'"
 #EOF#

Re: [PATCH] kernel-chktaint: add reporting for tainted modules

[Thorsten Leemhuis]

On 10/28/25 08:12, Randy Dunlap wrote:
> Check all loaded modules and report any that have their 'taint'
> flags set along with a count of all tainted modules.
> The tainted module output format is:
> <module_name>: taint=<flags>
> 
> Example output:
> 
> Kernel is "tainted" for the following reasons:
>  * externally-built ('out-of-tree') module was loaded  (#12)
>  * unsigned module was loaded (#13)
> Raw taint value as int/string: 12288/'G           OE      '

I wonder if it would be easier more readable if the format used above...
> Modules tainted: count=1
> dump_test: taint=OE

...would be reused here somewhat. Like this maybe?

Modules tainted: 1
 * dump_test (OE)

Anyway:

Acked-by: Thorsten Leemhuis <linux@leemhuis.info>

Ciao, Thorsten
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> ---
> Cc: Thorsten Leemhuis <linux@leemhuis.info>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: linux-doc@vger.kernel.org
> ---
>  tools/debugging/kernel-chktaint |   17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> --- linux-next-20251027.orig/tools/debugging/kernel-chktaint
> +++ linux-next-20251027/tools/debugging/kernel-chktaint
> @@ -211,9 +211,24 @@ else
>  	addout "J"
>  	echo " * fwctl's mutating debug interface was used (#19)"
>  fi
> +echo "Raw taint value as int/string: $taint/'$out'"
> +
> +# report on any tainted loadable modules
> +[ -r /sys/module/ ] && cnt=`grep [A-Z] /sys/module/*/taint | wc -l` || cnt=0
>  
> +if [ $cnt -ne 0 ]; then
> +	echo
> +	echo "Modules tainted: count=$cnt"
> +	for dir in `ls /sys/module` ; do
> +		if [ -r /sys/module/$dir/taint ]; then
> +			modtnt=`cat /sys/module/$dir/taint`
> +			[ "$modtnt" = "" ] || echo "$dir: taint=$modtnt"
> +		fi
> +	done
> +fi
> +
> +echo
>  echo "For a more detailed explanation of the various taint flags see"
>  echo " Documentation/admin-guide/tainted-kernels.rst in the Linux kernel sources"
>  echo " or https://kernel.org/doc/html/latest/admin-guide/tainted-kernels.html"
> -echo "Raw taint value as int/string: $taint/'$out'"
>  #EOF#
> 

Re: [PATCH] kernel-chktaint: add reporting for tainted modules

[Randy Dunlap]

On 10/28/25 3:05 AM, Thorsten Leemhuis wrote:
> On 10/28/25 08:12, Randy Dunlap wrote:
>> Check all loaded modules and report any that have their 'taint'
>> flags set along with a count of all tainted modules.
>> The tainted module output format is:
>> <module_name>: taint=<flags>
>>
>> Example output:
>>
>> Kernel is "tainted" for the following reasons:
>>  * externally-built ('out-of-tree') module was loaded  (#12)
>>  * unsigned module was loaded (#13)
>> Raw taint value as int/string: 12288/'G           OE      '
> 
> I wonder if it would be easier more readable if the format used above...
>> Modules tainted: count=1
>> dump_test: taint=OE
> 
> ...would be reused here somewhat. Like this maybe?
> 
> Modules tainted: 1
>  * dump_test (OE)

Yeah, I like that. Thanks.

-- 
~Randy