From: "Michael S. Tsirkin" <mst@redhat.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: linux-kernel@vger.kernel.org, "open list:VIRTIO CORE,
NET..." <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH 2/2] virtio: don't free memory until the underlying struct device has been released
Date: Sun, 4 Jan 2015 17:40:49 +0200 [thread overview]
Message-ID: <20150104154049.GA6546@redhat.com> (raw)
In-Reply-To: <54A9563F.3070902@oracle.com>
On Sun, Jan 04, 2015 at 10:03:27AM -0500, Sasha Levin wrote:
> On 01/04/2015 06:26 AM, Michael S. Tsirkin wrote:
> > On Fri, Jan 02, 2015 at 02:47:40PM -0500, Sasha Levin wrote:
> >> > When releasing a virtio device, We can't free a struct virtio_device until the
> >> > underlying struct device has been released, which might not happen immediately
> >> > on device_unregister() even if that was the device's last reference.
> >> >
> >> > Instead, free the memory only once we know the device is gone in the release
> >> > callback.
> >> >
> >> > Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> >
> > Isn't this an old bug: do we need to copy stable on a fix?
> >
> > What is the behaviour without this patch?
> > Is there a way to make this cause a crash?
>
> It will oops if CONFIG_DEBUG_KOBJECT_RELEASE is enabled. I guess
> it needs to go to stable as well.
>
>
> Thanks,
> Sasha
I see.
It's probably a good idea to document the crash in the commit log,
and also add a code comment.
I'll post the series with these minor tweaks, please confirm
that this fixes the issues for you.
--
MST
next prev parent reply other threads:[~2015-01-04 15:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-02 19:47 [PATCH 1/2] virtio_pci: double free and invalid memory access of device vqs Sasha Levin
2015-01-02 19:47 ` [PATCH 2/2] virtio: don't free memory until the underlying struct device has been released Sasha Levin
2015-01-04 11:26 ` Michael S. Tsirkin
2015-01-04 15:03 ` Sasha Levin
2015-01-04 15:40 ` Michael S. Tsirkin [this message]
2015-01-04 11:12 ` [PATCH 1/2] virtio_pci: double free and invalid memory access of device vqs Michael S. Tsirkin
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