kernel-chktaint: add reporting for tainted modules

Check all loaded modules and report any that have their 'taint'
flags set.  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      '

Tainted modules:
 * dump_test (OE)

Link: https://lkml.kernel.org/r/20260115064756.531592-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Thorsten Leemhuis <linux@leemhuis.info>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/debugging/kernel-chktaint

@@ -211,9 +211,25 @@ 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
+[ "$1" = "" ] && [ -r /sys/module/ ] && \
+	cnt=`grep [A-Z] /sys/module/*/taint | wc -l` || cnt=0
+
+if [ $cnt -ne 0 ]; then
+	echo
+	echo "Tainted modules:"
+	for dir in `ls /sys/module` ; do
+		if [ -r /sys/module/$dir/taint ]; then
+			modtnt=`cat /sys/module/$dir/taint`
+			[ "$modtnt" = "" ] || echo " * $dir ($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#