Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot
From: Eugenio Pérez <eperezma@redhat.com>
Date: 2020-02-11 09:33:48
Also in:
kvm, linux-next, lkml
Subsystem:
the rest, virtio host (vhost) · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
Possibly related (same subject, not in this thread)
- 2020-02-10 · Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot · Christian Borntraeger <hidden>
- 2020-02-07 · Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot · "Michael S. Tsirkin" <mst@redhat.com>
- 2020-02-07 · Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot · Cornelia Huck <cohuck@redhat.com>
- 2020-02-07 · Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot · Christian Borntraeger <hidden>
- 2020-02-07 · Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot · "Michael S. Tsirkin" <mst@redhat.com>
On Mon, 2020-02-10 at 12:01 +0100, Christian Borntraeger wrote:
On 10.02.20 10:47, Eugenio Perez Martin wrote:quoted
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 the hints. Could we add some debug traces? Something like the inline patch should give us some clues. Thanks! From a8d65d5f0ae3d305443ee84b4842b7c712a1ac1d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com> Date: Tue, 11 Feb 2020 10:29:01 +0100 Subject: [PATCH] Add some traces --- drivers/vhost/vhost.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b5a51b1f2e79..60c048eebe4d 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c@@ -2239,8 +2239,8 @@ static int fetch_buf(struct vhost_virtqueue *vq) vq->avail_idx = vhost16_to_cpu(vq, avail_idx); if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { - vq_err(vq, "Guest moved used index from %u to %u", - last_avail_idx, vq->avail_idx); + vq_err(vq, "Guest moved vq %p used index from %u to %u", + vq, last_avail_idx, vq->avail_idx); return -EFAULT; }
@@ -2336,6 +2336,8 @@ static int fetch_descs(struct vhost_virtqueue *vq) while (!ret && vq->ndescs <= vq->batch_descs) ret = fetch_buf(vq); + pr_debug("[vq=%p][vq->ndescs=%d]", vq, vq->ndescs); + return vq->ndescs ? 0 : ret; }
@@ -2416,6 +2418,8 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, } vq->first_desc = i + 1; + pr_debug("[vq=%p][vq->ndescs=%d][vq->first_desc=%d]", vq, vq->ndescs, + vq->first_desc); return ret;
@@ -2459,6 +2463,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, start = vq->last_used_idx & (vq->num - 1); used = vq->used->ring + start; + pr_debug("[vq=%p][start=%d][count=%u]", vq, start, count); if (vhost_put_used(vq, heads, start, count)) { vq_err(vq, "Failed to write used"); return -EFAULT;
--
2.18.1