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Date: Fri, 14 Feb 2020 08:47:23 +0100
From: Christian Borntraeger <borntraeger@...ibm.com>
To: Eugenio Perez Martin <eperezma@...hat.com>
Cc: "Michael S. Tsirkin" <mst@...hat.com>,
"virtualization@...ts.linux-foundation.org"
<virtualization@...ts.linux-foundation.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Linux Next Mailing List <linux-next@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
kvm list <kvm@...r.kernel.org>,
Halil Pasic <pasic@...ux.ibm.com>,
Cornelia Huck <cohuck@...hat.com>
Subject: Re: vhost changes (batched) in linux-next after 12/13 trigger random
crashes in KVM guests after reboot
repro
On 14.02.20 08:43, Christian Borntraeger wrote:
>
>
> On 14.02.20 08:40, Eugenio Perez Martin wrote:
>> Hi.
>>
>> Were the vhost and vhost_net modules loaded with dyndbg='+plt'? I miss
>> all the others regular debug traces on that one.
>
> I did
>
> echo -n 'file drivers/vhost/vhost.c +plt' > control
> and
> echo -n 'file drivers/vhost/net.c +plt' > control
>
> but apparently it did not work...me hates dynamic debug.
>
>>
>> Thanks!
>>
>> On Fri, Feb 14, 2020 at 8:34 AM Christian Borntraeger
>> <borntraeger@...ibm.com> wrote:
>>>
>>> I did
>>> ping -c 20 -f ... ; reboot
>>> twice
>>>
>>> The ping after the first reboot showed .......E
>>>
>>> this was on the host console
>>>
>>> [ 55.951885] CPU: 34 PID: 1908 Comm: CPU 0/KVM Not tainted 5.5.0+ #21
>>> [ 55.951891] Hardware name: IBM 3906 M04 704 (LPAR)
>>> [ 55.951892] Call Trace:
>>> [ 55.951902] [<0000001ede114132>] show_stack+0x8a/0xd0
>>> [ 55.951906] [<0000001edeb0672a>] dump_stack+0x8a/0xb8
>>> [ 55.951915] [<000003ff803736a6>] vhost_vring_ioctl+0x6fe/0x858 [vhost]
>>> [ 55.951919] [<000003ff8042a608>] vhost_net_ioctl+0x510/0x570 [vhost_net]
>>> [ 55.951924] [<0000001ede3c4dd8>] do_vfs_ioctl+0x430/0x6f8
>>> [ 55.951926] [<0000001ede3c5124>] ksys_ioctl+0x84/0xb0
>>> [ 55.951927] [<0000001ede3c51ba>] __s390x_sys_ioctl+0x2a/0x38
>>> [ 55.951931] [<0000001edeb27f72>] system_call+0x2a6/0x2c8
>>> [ 55.951949] CPU: 34 PID: 1908 Comm: CPU 0/KVM Not tainted 5.5.0+ #21
>>> [ 55.951950] Hardware name: IBM 3906 M04 704 (LPAR)
>>> [ 55.951951] Call Trace:
>>> [ 55.951952] [<0000001ede114132>] show_stack+0x8a/0xd0
>>> [ 55.951954] [<0000001edeb0672a>] dump_stack+0x8a/0xb8
>>> [ 55.951956] [<000003ff803736a6>] vhost_vring_ioctl+0x6fe/0x858 [vhost]
>>> [ 55.951958] [<000003ff8042a608>] vhost_net_ioctl+0x510/0x570 [vhost_net]
>>> [ 55.951959] [<0000001ede3c4dd8>] do_vfs_ioctl+0x430/0x6f8
>>> [ 55.951961] [<0000001ede3c5124>] ksys_ioctl+0x84/0xb0
>>> [ 55.951962] [<0000001ede3c51ba>] __s390x_sys_ioctl+0x2a/0x38
>>> [ 55.951964] [<0000001edeb27f72>] system_call+0x2a6/0x2c8
>>> [ 55.951997] Guest moved vq 0000000063d896c6 used index from 44 to 0
>>> [ 56.609831] unexpected descriptor format for RX: out 0, in 0
>>> [ 86.540460] CPU: 6 PID: 1908 Comm: CPU 0/KVM Not tainted 5.5.0+ #21
>>> [ 86.540464] Hardware name: IBM 3906 M04 704 (LPAR)
>>> [ 86.540466] Call Trace:
>>> [ 86.540473] [<0000001ede114132>] show_stack+0x8a/0xd0
>>> [ 86.540477] [<0000001edeb0672a>] dump_stack+0x8a/0xb8
>>> [ 86.540486] [<000003ff803736a6>] vhost_vring_ioctl+0x6fe/0x858 [vhost]
>>> [ 86.540490] [<000003ff8042a608>] vhost_net_ioctl+0x510/0x570 [vhost_net]
>>> [ 86.540494] [<0000001ede3c4dd8>] do_vfs_ioctl+0x430/0x6f8
>>> [ 86.540496] [<0000001ede3c5124>] ksys_ioctl+0x84/0xb0
>>> [ 86.540498] [<0000001ede3c51ba>] __s390x_sys_ioctl+0x2a/0x38
>>> [ 86.540501] [<0000001edeb27f72>] system_call+0x2a6/0x2c8
>>> [ 86.540524] CPU: 6 PID: 1908 Comm: CPU 0/KVM Not tainted 5.5.0+ #21
>>> [ 86.540525] Hardware name: IBM 3906 M04 704 (LPAR)
>>> [ 86.540526] Call Trace:
>>> [ 86.540527] [<0000001ede114132>] show_stack+0x8a/0xd0
>>> [ 86.540528] [<0000001edeb0672a>] dump_stack+0x8a/0xb8
>>> [ 86.540531] [<000003ff803736a6>] vhost_vring_ioctl+0x6fe/0x858 [vhost]
>>> [ 86.540532] [<000003ff8042a608>] vhost_net_ioctl+0x510/0x570 [vhost_net]
>>> [ 86.540534] [<0000001ede3c4dd8>] do_vfs_ioctl+0x430/0x6f8
>>> [ 86.540536] [<0000001ede3c5124>] ksys_ioctl+0x84/0xb0
>>> [ 86.540537] [<0000001ede3c51ba>] __s390x_sys_ioctl+0x2a/0x38
>>> [ 86.540538] [<0000001edeb27f72>] system_call+0x2a6/0x2c8
>>> [ 86.540570] unexpected descriptor format for RX: out 0, in 0
>>> [ 86.540577] Unexpected header len for TX: 0 expected 0
>>>
>>>
>>> On 14.02.20 08:06, Eugenio Pérez wrote:
>>>> Hi Christian.
>>>>
>>>> Sorry, that was meant to be applied over previous debug patch.
>>>>
>>>> Here I inline the one meant to be applied over eccb852f1fe6bede630e2e4f1a121a81e34354ab.
>>>>
>>>> Thanks!
>>>>
>>>> From d978ace99e4844b49b794d768385db3d128a4cc0 Mon Sep 17 00:00:00 2001
>>>> From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@...hat.com>
>>>> Date: Fri, 14 Feb 2020 08:02:26 +0100
>>>> Subject: [PATCH] vhost: disable all features and trace last_avail_idx and
>>>> ioctl calls
>>>>
>>>> ---
>>>> drivers/vhost/net.c | 20 +++++++++++++++++---
>>>> drivers/vhost/vhost.c | 25 +++++++++++++++++++++++--
>>>> drivers/vhost/vhost.h | 10 +++++-----
>>>> 3 files changed, 45 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
>>>> index e158159671fa..e4d5f843f9c0 100644
>>>> --- a/drivers/vhost/net.c
>>>> +++ b/drivers/vhost/net.c
>>>> @@ -1505,10 +1505,13 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
>>>>
>>>> mutex_lock(&n->dev.mutex);
>>>> r = vhost_dev_check_owner(&n->dev);
>>>> - if (r)
>>>> + if (r) {
>>>> + pr_debug("vhost_dev_check_owner index=%u fd=%d rc r=%d", index, fd, r);
>>>> goto err;
>>>> + }
>>>>
>>>> if (index >= VHOST_NET_VQ_MAX) {
>>>> + pr_debug("vhost_dev_check_owner index=%u fd=%d MAX=%d", index, fd, VHOST_NET_VQ_MAX);
>>>> r = -ENOBUFS;
>>>> goto err;
>>>> }
>>>> @@ -1518,22 +1521,26 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
>>>>
>>>> /* Verify that ring has been setup correctly. */
>>>> if (!vhost_vq_access_ok(vq)) {
>>>> + pr_debug("vhost_net_set_backend index=%u fd=%d !vhost_vq_access_ok", index, fd);
>>>> r = -EFAULT;
>>>> goto err_vq;
>>>> }
>>>> sock = get_socket(fd);
>>>> if (IS_ERR(sock)) {
>>>> r = PTR_ERR(sock);
>>>> + pr_debug("vhost_net_set_backend index=%u fd=%d get_socket err r=%d", index, fd, r);
>>>> goto err_vq;
>>>> }
>>>>
>>>> /* start polling new socket */
>>>> oldsock = vq->private_data;
>>>> if (sock != oldsock) {
>>>> + pr_debug("sock=%p != oldsock=%p index=%u fd=%d vq=%p", sock, oldsock, index, fd, vq);
>>>> ubufs = vhost_net_ubuf_alloc(vq,
>>>> sock && vhost_sock_zcopy(sock));
>>>> if (IS_ERR(ubufs)) {
>>>> r = PTR_ERR(ubufs);
>>>> + pr_debug("ubufs index=%u fd=%d err r=%d vq=%p", index, fd, r, vq);
>>>> goto err_ubufs;
>>>> }
>>>>
>>>> @@ -1541,11 +1548,15 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
>>>> vq->private_data = sock;
>>>> vhost_net_buf_unproduce(nvq);
>>>> r = vhost_vq_init_access(vq);
>>>> - if (r)
>>>> + if (r) {
>>>> + pr_debug("init_access index=%u fd=%d r=%d vq=%p", index, fd, r, vq);
>>>> goto err_used;
>>>> + }
>>>> r = vhost_net_enable_vq(n, vq);
>>>> - if (r)
>>>> + if (r) {
>>>> + pr_debug("enable_vq index=%u fd=%d r=%d vq=%p", index, fd, r, vq);
>>>> goto err_used;
>>>> + }
>>>> if (index == VHOST_NET_VQ_RX)
>>>> nvq->rx_ring = get_tap_ptr_ring(fd);
>>>>
>>>> @@ -1559,6 +1570,8 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
>>>>
>>>> mutex_unlock(&vq->mutex);
>>>>
>>>> + pr_debug("sock=%p", sock);
>>>> +
>>>> if (oldubufs) {
>>>> vhost_net_ubuf_put_wait_and_free(oldubufs);
>>>> mutex_lock(&vq->mutex);
>>>> @@ -1710,6 +1723,7 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
>>>>
>>>> switch (ioctl) {
>>>> case VHOST_NET_SET_BACKEND:
>>>> + pr_debug("VHOST_NET_SET_BACKEND");
>>>> if (copy_from_user(&backend, argp, sizeof backend))
>>>> return -EFAULT;
>>>> return vhost_net_set_backend(n, backend.index, backend.fd);
>>>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>>>> index b5a51b1f2e79..ec25ba32fe81 100644
>>>> --- a/drivers/vhost/vhost.c
>>>> +++ b/drivers/vhost/vhost.c
>>>> @@ -1642,15 +1642,30 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
>>>> r = -EINVAL;
>>>> break;
>>>> }
>>>> +
>>>> + if (vq->last_avail_idx || vq->avail_idx) {
>>>> + pr_debug(
>>>> + "strange VHOST_SET_VRING_BASE [vq=%p][s.index=%u][s.num=%u]",
>>>> + vq, s.index, s.num);
>>>> + dump_stack();
>>>> + r = 0;
>>>> + break;
>>>> + }
>>>> vq->last_avail_idx = s.num;
>>>> /* Forget the cached index value. */
>>>> vq->avail_idx = vq->last_avail_idx;
>>>> + pr_debug(
>>>> + "VHOST_SET_VRING_BASE [vq=%p][vq->last_avail_idx=%u][vq->avail_idx=%u][s.index=%u][s.num=%u]",
>>>> + vq, vq->last_avail_idx, vq->avail_idx, s.index, s.num);
>>>> break;
>>>> case VHOST_GET_VRING_BASE:
>>>> s.index = idx;
>>>> s.num = vq->last_avail_idx;
>>>> if (copy_to_user(argp, &s, sizeof s))
>>>> r = -EFAULT;
>>>> + pr_debug(
>>>> + "VHOST_GET_VRING_BASE [vq=%p][vq->last_avail_idx=%u][vq->avail_idx=%u][s.index=%u][s.num=%u]",
>>>> + vq, vq->last_avail_idx, vq->avail_idx, s.index, s.num);
>>>> break;
>>>> case VHOST_SET_VRING_KICK:
>>>> if (copy_from_user(&f, argp, sizeof f)) {
>>>> @@ -2239,8 +2254,8 @@ 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;
>>>> }
>>>>
>>>> @@ -2316,6 +2331,9 @@ static int fetch_buf(struct vhost_virtqueue *vq)
>>>> BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
>>>>
>>>> /* On success, increment avail index. */
>>>> + pr_debug(
>>>> + "[vq=%p][vq->last_avail_idx=%u][vq->avail_idx=%u][vq->ndescs=%d][vq->first_desc=%d]",
>>>> + vq, vq->last_avail_idx, vq->avail_idx, vq->ndescs, vq->first_desc);
>>>> vq->last_avail_idx++;
>>>>
>>>> return 0;
>>>> @@ -2432,6 +2450,9 @@ EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
>>>> /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
>>>> void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
>>>> {
>>>> + pr_debug(
>>>> + "DISCARD [vq=%p][vq->last_avail_idx=%u][vq->avail_idx=%u][n=%d]",
>>>> + vq, vq->last_avail_idx, vq->avail_idx, n);
>>>> vq->last_avail_idx -= n;
>>>> }
>>>> EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
>>>> 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)
>>>> };
>>>>
>>>>
>>>
>>
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