test_firmware: add test case for SIGCHLD on sync fallback

It has been reported that SIGCHLD will trigger an immediate abort
on sync firmware requests which rely on the sysfs interface for a
trigger. This is unexpected behaviour, this reproduces this issue.

This test case currenty fails.

Reported-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/testing/selftests/firmware/fw_fallback.sh b/tools/testing/selftests/firmware/fw_fallback.sh
index 2e4c22d5abf7dc6b3b9704103ac63da61f9c5688..8f511035f78331410fdba45ebea6081345cdce4c 100755 (executable)
--- a/tools/testing/selftests/firmware/fw_fallback.sh
+++ b/tools/testing/selftests/firmware/fw_fallback.sh
@@ -134,6 +134,27 @@ load_fw_custom_cancel()
        wait
 }
 
+load_fw_fallback_with_child()
+{
+       local name="$1"
+       local file="$2"
+
+       # This is the value already set but we want to be explicit
+       echo 4 >/sys/class/firmware/timeout
+
+       sleep 1 &
+       SECONDS_BEFORE=$(date +%s)
+       echo -n "$name" >"$DIR"/trigger_request 2>/dev/null
+       SECONDS_AFTER=$(date +%s)
+       SECONDS_DELTA=$(($SECONDS_AFTER - $SECONDS_BEFORE))
+       if [ "$SECONDS_DELTA" -lt 4 ]; then
+               RET=1
+       else
+               RET=0
+       fi
+       wait
+       return $RET
+}
 
 trap "test_finish" EXIT
 
@@ -221,4 +242,14 @@ else
        echo "$0: cancelling custom fallback mechanism works"
 fi
 
+set +e
+load_fw_fallback_with_child "nope-signal-$NAME" "$FW"
+if [ "$?" -eq 0 ]; then
+       echo "$0: SIGCHLD on sync ignored as expected" >&2
+else
+       echo "$0: error - sync firmware request cancelled due to SIGCHLD" >&2
+       exit 1
+fi
+set -e
+
 exit 0