linux-kernel - Re: [Pv-drivers] [PATCH 05/12] VMCI: event handling implementation.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 29 Oct 2012 21:58:21 -0700
From:	Dmitry Torokhov <dtor@...are.com>
To:	Greg KH <gregkh@...uxfoundation.org>
Cc:	George Zhang <georgezhang@...are.com>, pv-drivers@...are.com,
	linux-kernel@...r.kernel.org,
	virtualization@...ts.linux-foundation.org
Subject: Re: [Pv-drivers] [PATCH 05/12] VMCI: event handling implementation.

On Mon, Oct 29, 2012 at 07:24:46PM -0700, Greg KH wrote:
> On Mon, Oct 29, 2012 at 06:04:27PM -0700, George Zhang wrote:
> > +/*
> > + * Releases the given VMCISubscription.
> > + * Fires the destroy event if the reference count has gone to zero.
> > + */
> > +static void event_release(struct vmci_subscription *entry)
> > +{
> > +	kref_put(&entry->kref, event_signal_destroy);
> > +}
> 
> Same question as before with the kref_put() call, what is handling the
> locking here?  It looks like a race to me.

The reference is taken only if event is on the list (which managed by
RCU and a mutex), so it is not possible to go from 0->1 for that
refcount.

Thanks,
Dmitry

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/