linux-kernel - [PATCH v4 1/5] test_firmware: add test case for SIGCHLD on sync fallback

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Date:   Thu, 20 Jul 2017 13:13:38 -0700
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     gregkh@...uxfoundation.org
Cc:     wagi@...om.org, yi1.li@...ux.intel.com, takahiro.akashi@...aro.org,
        bjorn.andersson@...aro.org, luto@...nel.org, ebiederm@...ssion.com,
        dmitry.torokhov@...il.com, arend.vanspriel@...adcom.com,
        dwmw2@...radead.org, rjw@...ysocki.net, atull@...nel.org,
        moritz.fischer@...us.com, pmladek@...e.com,
        johannes.berg@...el.com, emmanuel.grumbach@...el.com,
        luciano.coelho@...el.com, kvalo@...eaurora.org,
        torvalds@...ux-foundation.org, keescook@...omium.org,
        dhowells@...hat.com, pjones@...hat.com, hdegoede@...hat.com,
        alan@...ux.intel.com, tytso@....edu, dave@...olabs.net,
        mawilcox@...rosoft.com, tglx@...utronix.de, peterz@...radead.org,
        mfuzzey@...keon.com, jakub.kicinski@...ronome.com,
        nbroeking@...com, jewalt@...innovations.com,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Luis R. Rodriguez" <mcgrof@...nel.org>
Subject: [PATCH v4 1/5] 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@...keon.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
---
 tools/testing/selftests/firmware/fw_fallback.sh | 31 +++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/tools/testing/selftests/firmware/fw_fallback.sh b/tools/testing/selftests/firmware/fw_fallback.sh
index 2e4c22d5abf7..8f511035f783 100755
--- 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
-- 
2.11.0