From: "Michael S. Tsirkin" <mst@redhat.com>
To: Suman Anna <s-anna@ti.com>
Cc: Jason Wang <jasowang@redhat.com>, Tiwei Bie <tiwei.bie@intel.com>,
"David S. Miller" <davem@davemloft.net>,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org
Subject: Re: [PATCH] virtio_ring: Fix mem leak with vring_new_virtqueue()
Date: Sun, 8 Mar 2020 03:58:05 -0400 [thread overview]
Message-ID: <20200308035751-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <a4335428-e29e-d567-b18b-3c144020a726@ti.com>
On Thu, Mar 05, 2020 at 06:27:53PM -0600, Suman Anna wrote:
> On 2/25/20 9:13 PM, Jason Wang wrote:
> >
> > On 2020/2/26 上午12:51, Suman Anna wrote:
> >> Hi Jason,
> >>
> >> On 2/24/20 11:39 PM, Jason Wang wrote:
> >>> On 2020/2/25 上午5:26, Suman Anna wrote:
> >>>> The functions vring_new_virtqueue() and __vring_new_virtqueue() are
> >>>> used
> >>>> with split rings, and any allocations within these functions are
> >>>> managed
> >>>> outside of the .we_own_ring flag. The commit cbeedb72b97a
> >>>> ("virtio_ring:
> >>>> allocate desc state for split ring separately") allocates the desc
> >>>> state
> >>>> within the __vring_new_virtqueue() but frees it only when the
> >>>> .we_own_ring
> >>>> flag is set. This leads to a memory leak when freeing such allocated
> >>>> virtqueues with the vring_del_virtqueue() function.
> >>>>
> >>>> Fix this by moving the desc_state free code outside the flag and only
> >>>> for split rings. Issue was discovered during testing with remoteproc
> >>>> and virtio_rpmsg.
> >>>>
> >>>> Fixes: cbeedb72b97a ("virtio_ring: allocate desc state for split ring
> >>>> separately")
> >>>> Signed-off-by: Suman Anna<s-anna@ti.com>
> >>>> ---
> >>>> drivers/virtio/virtio_ring.c | 4 ++--
> >>>> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/drivers/virtio/virtio_ring.c
> >>>> b/drivers/virtio/virtio_ring.c
> >>>> index 867c7ebd3f10..58b96baa8d48 100644
> >>>> --- a/drivers/virtio/virtio_ring.c
> >>>> +++ b/drivers/virtio/virtio_ring.c
> >>>> @@ -2203,10 +2203,10 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> >>>> vq->split.queue_size_in_bytes,
> >>>> vq->split.vring.desc,
> >>>> vq->split.queue_dma_addr);
> >>>> -
> >>>> - kfree(vq->split.desc_state);
> >>>> }
> >>>> }
> >>>> + if (!vq->packed_ring)
> >>>> + kfree(vq->split.desc_state);
> >>> Nitpick, it looks to me it would be more clear if we just free
> >>> desc_state unconditionally here (and remove the kfree for packed above).
> >> OK, are you sure you want that to be folded into this patch? It looks to
> >> me a separate cleanup/consolidation patch, and packed desc_state does
> >> not suffer this memleak, and need not be backported into stable kernels.
> >>
> >> regards
> >> Suman
> >
> >
> > Though it's just a small tweak, I'm fine for leaving it for future.
> >
> > So
> >
> > Acked-by: Jason Wang <jasowang@redhat.com>
> >
>
> Mike,
> Ping on this. I don't see the patch in -next yet. Can we get this into
> the current -rc please?
>
> regards
> Suman
Yes will queue it shortly, thanks!
prev parent reply other threads:[~2020-03-08 7:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 21:26 [PATCH] virtio_ring: Fix mem leak with vring_new_virtqueue() Suman Anna
2020-02-25 5:39 ` Jason Wang
2020-02-25 16:51 ` Suman Anna
2020-02-26 3:13 ` Jason Wang
2020-02-26 17:01 ` Suman Anna
2020-03-06 0:27 ` Suman Anna
2020-03-08 7:58 ` Michael S. Tsirkin [this message]
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=20200308035751-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=davem@davemloft.net \
--cc=jasowang@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-remoteproc@vger.kernel.org \
--cc=s-anna@ti.com \
--cc=tiwei.bie@intel.com \
--cc=virtualization@lists.linux-foundation.org \
/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).