selftests/powerpc: Detect taint change in mitigation patching test

Currently the mitigation patching test errors out if the kernel is tainted prior to the test running. That causes the test to fail unnecessarily if some other test has caused the kernel to be tainted, or if a proprietary or force module is loaded for example. Instead just warn if the kernel is tainted to begin with, and only report a change in the taint state as an error in the test. Signed-off-by: Michael Ellerman <[email protected]> Link: https://patch.msgid.link/[email protected]
bergwolf · Nov 7, 2024 · a8a54a6 · a8a54a6
1 parent c6a7555
commit a8a54a6
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/tools/testing/selftests/powerpc/security/mitigation-patching.sh b/tools/testing/selftests/powerpc/security/mitigation-patching.sh
@@ -36,8 +36,7 @@ fi
 
 tainted=$(cat /proc/sys/kernel/tainted)
 if [[ "$tainted" -ne 0 ]]; then
-    echo "Error: kernel already tainted!" >&2
-    exit 1
+    echo "Warning: kernel already tainted! ($tainted)" >&2
 fi
 
 mitigations="barrier_nospec stf_barrier count_cache_flush rfi_flush entry_flush uaccess_flush"
@@ -68,9 +67,10 @@ fi
 echo "Waiting for timeout ..."
 wait
 
+orig_tainted=$tainted
 tainted=$(cat /proc/sys/kernel/tainted)
-if [[ "$tainted" -ne 0 ]]; then
-    echo "Error: kernel became tainted!" >&2
+if [[ "$tainted" != "$orig_tainted" ]]; then
+    echo "Error: kernel newly tainted, before ($orig_tainted) after ($tainted)" >&2
     exit 1
 fi