The patch below does not apply to the 4.16-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e538409257d0217a9bc715686100a5328db75a15 Mon Sep 17 00:00:00 2001

From: Ben Hutchings ben.hutchings@codethink.co.uk Date: Wed, 4 Apr 2018 22:38:49 +0200 Subject: [PATCH] test_firmware: fix setting old custom fw path back on exit, second try

Commit 65c79230576 tried to clear the custom firmware path on exit by writing a single space to the firmware_class.path parameter. This doesn't work because nothing strips this space from the value stored and fw_get_filesystem_firmware() only ignores zero-length paths.

Instead, write a null byte.

Fixes: 0a8adf58475 ("test: add firmware_class loader test") Fixes: 65c79230576 ("test_firmware: fix setting old custom fw path back on exit") Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Acked-by: Luis R. Rodriguez mcgrof@kernel.org Cc: stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/tools/testing/selftests/firmware/fw_lib.sh b/tools/testing/selftests/firmware/fw_lib.sh index 9ea31b57d71a..962d7f4ac627 100755 --- a/tools/testing/selftests/firmware/fw_lib.sh +++ b/tools/testing/selftests/firmware/fw_lib.sh @@ -154,11 +154,13 @@ test_finish() if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout fi - if [ "$OLD_FWPATH" = "" ]; then - OLD_FWPATH=" " - fi if [ "$TEST_REQS_FW_SET_CUSTOM_PATH" = "yes" ]; then - echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path + if [ "$OLD_FWPATH" = "" ]; then + # A zero-length write won't work; write a null byte + printf '\000' >/sys/module/firmware_class/parameters/path + else + echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path + fi fi if [ -f $FW ]; then rm -f "$FW"