From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugenio =?ISO-8859-1?Q?P=E9rez?= Subject: Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot Date: Wed, 12 Feb 2020 17:34:16 +0100 Message-ID: <50a79c3491ac483583c97df2fac29e2c3248fdea.camel@redhat.com> References: <20200107042401-mutt-send-email-mst@kernel.org> <20200107065434-mutt-send-email-mst@kernel.org> <20200120012724-mutt-send-email-mst@kernel.org> <2a63b15f-8cf5-5868-550c-42e2cfd92c60@de.ibm.com> <1ade56b5-083f-bb6f-d3e0-3ddcf78f4d26@de.ibm.com> <20200206171349-mutt-send-email-mst@kernel.org> <5c860fa1-cef5-b389-4ebf-99a62afa0fe8@de.ibm.com> <20200207025806-mutt-send-email-mst@kernel.org> <97c93d38-ef07-e321-d133-18483d54c0c0@de.ibm.com> <43a5dbaa-9129-e220-8483-45c60a82c945@de.ibm.com> <4c3f70b7-723a-8b0f-ac49-babef1bcc180@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <4c3f70b7-723a-8b0f-ac49-babef1bcc180@de.ibm.com> Sender: kvm-owner@vger.kernel.org To: Christian Borntraeger Cc: "Michael S. Tsirkin" , "virtualization@lists.linux-foundation.org" , Stephen Rothwell , Linux Next Mailing List , "linux-kernel@vger.kernel.org" , kvm list , Halil Pasic , Cornelia Huck List-Id: virtualization@lists.linuxfoundation.org On Tue, 2020-02-11 at 14:13 +0100, Christian Borntraeger wrote: > > On 11.02.20 14:04, Eugenio Pérez wrote: > > On Mon, 2020-02-10 at 12:01 +0100, Christian Borntraeger wrote: > > > On 10.02.20 10:47, Eugenio Perez Martin wrote: > > > > Hi Christian. > > > > > > > > I'm not able to reproduce the failure with eccb852f1fe6bede630e2e4f1a121a81e34354ab commit. Could you add more > > > > data? > > > > Your configuration (libvirt or qemu line), and host's dmesg output if any? > > > > > > > > Thanks! > > > > > > If it was not obvious, this is on s390x, a big endian system. > > > > > > > Hi Christian. Thank you very much for your fast responses. > > > > Could you try this patch on top of eccb852f1fe6bede630e2e4f1a121a81e34354ab? > > I still get > [ 43.665145] Guest moved used index from 0 to 289 > after some reboots. > > > > Thanks! > > > > From 71d0f9108a18aa894cc0c0c1c7efbad39f465a27 Mon Sep 17 00:00:00 2001 > > From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= < > > eperezma@redhat.com> > > Date: Tue, 11 Feb 2020 13:19:10 +0100 > > Subject: [PATCH] vhost: fix return value of vhost_get_vq_desc > > > > Before of the batch change, it was the chain's head. Need to keep that > > way or we will not be able to free a chain of descriptors. > > > > Fixes: eccb852f1fe6 ("vhost: batching fetches") > > --- > > drivers/vhost/vhost.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > index b5a51b1f2e79..fc422c3e5c08 100644 > > --- a/drivers/vhost/vhost.c > > +++ b/drivers/vhost/vhost.c > > @@ -2409,12 +2409,11 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, > > *out_num += ret; > > } > > > > - ret = desc->id; > > - > > if (!(desc->flags & VRING_DESC_F_NEXT)) > > break; > > } > > > > + ret = vq->descs[vq->first_desc].id; > > vq->first_desc = i + 1; > > > > return ret; > > Sorry, still not able to reproduce the issue. Could we try to disable all the vhost features? Thanks! diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 661088ae6dc7..08f6d2ccb697 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -250,11 +250,11 @@ int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled); } while (0) enum { - VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | - (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | - (1ULL << VIRTIO_RING_F_EVENT_IDX) | - (1ULL << VHOST_F_LOG_ALL) | - (1ULL << VIRTIO_F_ANY_LAYOUT) | + VHOST_FEATURES = /* (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | */ + /* (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | */ + /* (1ULL << VIRTIO_RING_F_EVENT_IDX) | */ + /* (1ULL << VHOST_F_LOG_ALL) | */ + /* (1ULL << VIRTIO_F_ANY_LAYOUT) | */ (1ULL << VIRTIO_F_VERSION_1) };