From: Miroslav Benes <mbenes@suse.cz>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: jeyu@kernel.org, jikos@kernel.org, pmladek@suse.com,
lpechacek@suse.cz, pavel@ucw.cz, live-patching@vger.kernel.org,
linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: Re: [PATCH v3 1/2] livepatch: send a fake signal to all blocking tasks
Date: Fri, 3 Nov 2017 09:06:55 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.21.1711030903110.31648@pobox.suse.cz> (raw)
In-Reply-To: <20171102133200.abwvepjx3ytufsc4@treble>
On Thu, 2 Nov 2017, Josh Poimboeuf wrote:
> On Tue, Oct 31, 2017 at 12:48:52PM +0100, Miroslav Benes wrote:
> > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> > index bf8c8fd72589..b7c60662baf3 100644
> > --- a/kernel/livepatch/core.c
> > +++ b/kernel/livepatch/core.c
> > @@ -440,6 +440,7 @@ EXPORT_SYMBOL_GPL(klp_enable_patch);
> > * /sys/kernel/livepatch/<patch>
> > * /sys/kernel/livepatch/<patch>/enabled
> > * /sys/kernel/livepatch/<patch>/transition
> > + * /sys/kernel/livepatch/<patch>/signal
> > * /sys/kernel/livepatch/<patch>/<object>
> > * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
> > */
> > @@ -514,11 +515,37 @@ static ssize_t transition_show(struct kobject *kobj,
> > patch == klp_transition_patch);
> > }
> >
> > +static ssize_t signal_store(struct kobject *kobj, struct kobj_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + int ret;
> > + bool val;
> > +
> > + /*
> > + * klp_mutex lock is not grabbed here intentionally. It is not really
> > + * needed. The race window is harmless and grabbing the lock would only
> > + * hold the action back.
> > + */
> > + if (!klp_transition_patch)
> > + return -EINVAL;
> > +
> > + ret = kstrtobool(buf, &val);
> > + if (ret)
> > + return ret;
> > +
> > + if (val)
> > + klp_force_signals();
> > +
> > + return count;
> > +}
>
> The function still has global functionality even though the sysfs entry
> is now per-patch. So if you do
>
> echo 1 > /sys/kernel/livepatch/patch1/signal
>
> But patch2 is in transition, then it will send signals based on patch2.
> Instead it should probably return an error.
>
> There's a similar issue with force_store().
Bah. I still find having "signal" and "force" in
/sys/kernel/livepatch/<patch>/ a bit odd, but I'll add
struct klp_patch *patch;
patch = container_of(kobj, struct klp_patch, kobj);
/*
...
*/
if (patch != klp_transition_patch)
return -EINVAL;
That should solve it for all cases.
Thanks,
Miroslav
next prev parent reply other threads:[~2017-11-03 8:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 11:48 [PATCH v3 0/2] livepatch: Introduce signal and force sysfs attributes Miroslav Benes
2017-10-31 11:48 ` [PATCH v3 1/2] livepatch: send a fake signal to all blocking tasks Miroslav Benes
2017-11-01 15:06 ` Miroslav Benes
2017-11-01 15:13 ` Petr Mladek
2017-11-01 16:43 ` Oleg Nesterov
2017-11-02 10:36 ` Miroslav Benes
2017-11-02 14:08 ` Oleg Nesterov
2017-11-02 13:09 ` Josh Poimboeuf
2017-11-03 8:02 ` Miroslav Benes
2017-11-03 12:57 ` Josh Poimboeuf
2017-11-02 13:32 ` Josh Poimboeuf
2017-11-03 8:06 ` Miroslav Benes [this message]
2017-11-06 11:08 ` Pavel Machek
2017-10-31 11:48 ` [PATCH v3 2/2] livepatch: force transition process to finish Miroslav Benes
2017-11-01 15:32 ` Petr Mladek
2017-11-02 13:13 ` Josh Poimboeuf
2017-11-03 8:07 ` Miroslav Benes
2017-11-06 11:11 ` Pavel Machek
2017-11-06 12:03 ` Jiri Kosina
2017-11-09 11:14 ` Pavel Machek
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