linux-kernel - Re: [PATCH 4.4 085/134] test_firmware: fix setting old custom fw path back on exit

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Date:   Tue, 3 Apr 2018 19:06:46 +0000
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     Ben Hutchings <ben.hutchings@...ethink.co.uk>
Cc:     "Luis R. Rodriguez" <mcgrof@...nel.org>, stable@...r.kernel.org,
        Sasha Levin <alexander.levin@...rosoft.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4.4 085/134] test_firmware: fix setting old custom fw
 path back on exit

On Sun, Apr 01, 2018 at 07:56:55PM +0100, Ben Hutchings wrote:
> On Mon, 2018-03-19 at 19:06 +0100, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: "Luis R. Rodriguez" <mcgrof@...nel.org>
> > 
> > 
> > [ Upstream commit 65c79230576873b312c3599479c1e42355c9f349 ]
> > 
> > The file /sys/module/firmware_class/parameters/path can be used
> > to set a custom firmware path. The fw_filesystem.sh script creates
> > a temporary directory to add a test firmware file to be used during
> > testing, in order for this to work it uses the custom path syfs file
> > and it was supposed to reset back the file on execution exit. The
> > script failed to do this due to a typo, it was using OLD_PATH instead
> > of OLD_FWPATH, since its inception since v3.17.
> > 
> > Its not as easy to just keep the old setting, it turns out that
> > resetting an empty setting won't actually do what we want, we need
> > to check if it was empty and set an empty space.
> 
> That doesn't seem to work either.  I don't see any stripping of spaces
> in the generic parameter code or firmware_class, and the parameter
> reads back as a space:
> 
> # echo -n ' ' > path
> # od -tx1 path
> 0000000 20 0a
> 0000002
> 
> However, this seems to work:
> 
> # printf '\0' > path 
> # od -tx1 path
> 0000000 0a
> 0000001

Not sure what you mean, care to send a patch?

  Luis
> 
> Ben.
> 
> > Without this we end up having the temporary path always set after
> > we run these tests.
> > 
> > Fixes: 0a8adf58475 ("test: add firmware_class loader test")
> > Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > ---
> >  tools/testing/selftests/firmware/fw_filesystem.sh |    5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > --- a/tools/testing/selftests/firmware/fw_filesystem.sh
> > +++ b/tools/testing/selftests/firmware/fw_filesystem.sh
> > @@ -28,7 +28,10 @@ test_finish()
> >  	if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
> >  		echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
> >  	fi
> > -	echo -n "$OLD_PATH" >/sys/module/firmware_class/parameters/path
> > +	if [ "$OLD_FWPATH" = "" ]; then
> > +		OLD_FWPATH=" "
> > +	fi
> > +	echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path
> >  	rm -f "$FW"
> >  	rmdir "$FWPATH"
> >  }
> > 
> > 
> > 
> -- 
> Ben Hutchings
> Software Developer, Codethink Ltd.
> 
> 

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