From: Minfei Huang <mhuang@redhat.com>
To: Miroslav Benes <mbenes@suse.cz>
Cc: "Minfei Huang" <mnfhuang@gmail.com>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"sjenning@redhat.com" <sjenning@redhat.com>,
"Jiri Kosina" <jkosina@suse.cz>,
"Vojtěch Pavlík" <vojtech@suse.cz>,
"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
pmladek@suse.cz
Subject: Re: [PATCH] livepatch: add module locking around kallsyms calls
Date: Tue, 2 Jun 2015 18:06:06 +0800 [thread overview]
Message-ID: <20150602100606.GA17412@dhcp-128-1.nay.redhat.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1506021106030.9729@pobox.suse.cz>
On 06/02/15 at 11:15am, Miroslav Benes wrote:
> On Tue, 2 Jun 2015, Minfei Huang wrote:
> > > - if (kallsyms_on_each_symbol(klp_verify_callback, &args))
> > > - return 0;
> > > + mutex_lock(&module_mutex);
> > > + ret = kallsyms_on_each_symbol(klp_verify_callback, &args);
> > > + mutex_unlock(&module_mutex);
> > >
> >
> > Hi.
> > In livepatch code path, returning value 0 may represent the right, but
> > sometime represent wrong, like the above function.
> >
> > Is it possible that we can wrap such function and return the unified
> > value? Thus we can not confuse the returning value any more.
>
> Hi,
>
> I must admit I do not understand. Both klp_find_object_symbol and
> klp_verify_vmlinux_symbol return 0 on success or -EINVAL. It is true that
> kallsyms_on_each_symbol and module_kallsyms_on_each symbol are different.
> That is why our kallsyms callbacks are different. See the implementation
> of those. But that is the API. Is this what you are worried about?
>
Sorry to confuse you about the unclear description.
Yes. kallsyms_on_each_symbol return 0 to imply the failure. I know we
should comply the API which we call from the other module, but it may be
better to wrap the API as a function, if the return value conflicts with
current rule.
Otherwise it may confuse someone that the error message will be printed,
although the return value is 0, like kallsyms_on_each_symbol.
But I do not insist my view.
Thanks
Minfei
> > Otherwise annotation is appreciate.
next prev parent reply other threads:[~2015-06-02 10:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-01 15:48 [PATCH] livepatch: add module locking around kallsyms calls Miroslav Benes
2015-06-02 2:52 ` Minfei Huang
2015-06-02 9:15 ` Miroslav Benes
2015-06-02 10:06 ` Minfei Huang [this message]
2015-06-02 15:09 ` Josh Poimboeuf
2015-06-02 20:58 ` Jiri Kosina
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150602100606.GA17412@dhcp-128-1.nay.redhat.com \
--to=mhuang@redhat.com \
--cc=jkosina@suse.cz \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=live-patching@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=mnfhuang@gmail.com \
--cc=pmladek@suse.cz \
--cc=sjenning@redhat.com \
--cc=vojtech@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).