Re: [PATCH] FIXUP: proc: Provide details on speculation flaw mitigations

From: Greg KH <gregkh@linuxfoundation.org>
To: Gwendal Grignou <gwendal@chromium.org>
Cc: stable@vger.kernel.org, groeck@chromium.org, keescook@chromium.org
Subject: Re: [PATCH] FIXUP: proc: Provide details on speculation flaw mitigations
Date: Mon, 14 Jan 2019 19:49:35 +0100	[thread overview]
Message-ID: <20190114184935.GA13821@kroah.com> (raw)
In-Reply-To: <CAPUE2usHg7gJRSTiJDCZyNXWQGuuF-bOJhcNNvznncZ1rLrm_Q@mail.gmail.com>

On Mon, Jan 14, 2019 at 10:00:54AM -0800, Gwendal Grignou wrote:
> On Sat, Jan 12, 2019 at 12:01 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Fri, Jan 11, 2019 at 04:32:12PM -0800, Gwendal Grignou wrote:
> > > Prevent an empty line in /proc/self/status, allow iotop to work.
> > >
> > > iotop does not like empty lines, fails with:
> > >   File "/usr/local/lib64/python2.7/site-packages/iotop/data.py", line
> > > 196, in parse_proc_pid_status
> > >     key, value = line.split(':\t', 1)
> > > ValueError: need more than 1 value to unpack
> > >
> > > [reading /proc/self/status]
> > >
> > > Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
> > > ---
> > >  fs/proc/array.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> >
> > Why send this to me?  Always use scripts/get_maintainer.pl on a patch to
> > determine who and what lists to send patches to.
> I did, your email address is on the first line:
> ./scripts/get_maintainer.pl
> 0001-CHROMIUM-FIXUP-proc-Provide-details-on-speculation-f.patch
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> (commit_signer:6/4=100%)

Ah, wait, you are making a patch against the stable kernel tree?

We can't go back in time, you need to work against Linus's latest kernel
tree, that's why I am showing up in this list.  I'm not the upstream
developer for this file.

> "Srivatsa S. Bhat" <srivatsa@csail.mit.edu> (commit_signer:3/4=75%)
> Thomas Gleixner <tglx@linutronix.de>
> (commit_signer:3/4=75%,authored:1/4=25%,added_lines:3/28=11%)
> David Woodhouse <dwmw@amazon.co.uk> (commit_signer:3/4=75%)
> Bo Gan <ganb@vmware.com> (commit_signer:3/4=75%)
> Kees Cook <keescook@chromium.org> (authored:1/4=25%,added_lines:23/28=82%)
> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> (authored:1/4=25%,removed_lines:1/2=50%)
> Gwendal Grignou <gwendal@chromium.org> (authored:1/4=25%,removed_lines:1/2=50%)
> linux-kernel@vger.kernel.org (open list)
> 
> >
> > And is this a new bug?  What commit caused this?
> It is only in 4.4 stable. It has been introduced by:
> "484964fa3e5a0 proc: Provide details on speculation flaw mitigations"

That really is commit fae1fa0fc6cca8beee3ab8ed71d54f9a78fa3f64 in
Linus's tree, and is in the 4.4, 4.9, 4.14, 4.16, and 4.17 kernel
releases.

So it also is included in 5.0-rc1, if this is still an issue there,
please submit the patch to the correct developers and then the patch
will be backported to the needed stable kernel trees if you add the
correct "Fixes:" and "cc: stable@stable.kernel.org" lines to the patch.
Documentation/SubmittingPatches will tell you all about how to do this.

> That patch adds an extra \n in front of "Speculation Store Bypass"
> that breaks iotop processing of /proc/../status.

Why isn't iotop broken in the latest kernel release?  It seems to work
for me here.

thanks,

greg k-h