Suman Anna
2020-Mar-06 00:27 UTC
[PATCH] virtio_ring: Fix mem leak with vring_new_virtqueue()
On 2/25/20 9:13 PM, Jason Wang wrote:> > On 2020/2/26 ??12:51, Suman Anna wrote: >> Hi Jason, >> >> On 2/24/20 11:39 PM, Jason Wang wrote: >>> On 2020/2/25 ??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 at 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 at 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
Michael S. Tsirkin
2020-Mar-08 07:58 UTC
[PATCH] virtio_ring: Fix mem leak with vring_new_virtqueue()
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 ??12:51, Suman Anna wrote: > >> Hi Jason, > >> > >> On 2/24/20 11:39 PM, Jason Wang wrote: > >>> On 2020/2/25 ??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 at 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 at 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 > SumanYes will queue it shortly, thanks!