From: Wei Wang <wei.w.wang@intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org,
pbonzini@redhat.com, liliang.opensource@gmail.com,
yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com,
riel@redhat.com
Subject: [virtio-dev] Re: [PATCH v22 2/3] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ
Date: Fri, 19 Jan 2018 14:24:11 +0800 [thread overview]
Message-ID: <5A618F0B.4090805@intel.com> (raw)
In-Reply-To: <20180117180337-mutt-send-email-mst@kernel.org>
On 01/18/2018 12:44 AM, Michael S. Tsirkin wrote:
> On Wed, Jan 17, 2018 at 01:10:11PM +0800, Wei Wang wrote:
>>
>> +static void virtballoon_changed(struct virtio_device *vdev)
>> +{
>> + struct virtio_balloon *vb = vdev->priv;
>> + unsigned long flags;
>> + __u32 cmd_id;
>> + s64 diff = towards_target(vb);
>> +
>> + if (diff) {
>> + spin_lock_irqsave(&vb->stop_update_lock, flags);
>> + if (!vb->stop_update)
> Why do you ignore stop_update for freeze?
> This means new wq entries can be added during remove
> causing use after free issues.
I think stop_update isn't needed, because the lock has already been
handled internally by the APIs. Similar examples like
mem_cgroup_css_free() in "mm/memcontrol.c", there is no such locks used
for cancel_work_sync(&memcg->high_work).
Best,
Wei
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WARNING: multiple messages have this Message-ID (diff)
From: Wei Wang <wei.w.wang@intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org,
pbonzini@redhat.com, liliang.opensource@gmail.com,
yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com,
riel@redhat.com
Subject: Re: [PATCH v22 2/3] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ
Date: Fri, 19 Jan 2018 14:24:11 +0800 [thread overview]
Message-ID: <5A618F0B.4090805@intel.com> (raw)
In-Reply-To: <20180117180337-mutt-send-email-mst@kernel.org>
On 01/18/2018 12:44 AM, Michael S. Tsirkin wrote:
> On Wed, Jan 17, 2018 at 01:10:11PM +0800, Wei Wang wrote:
>>
>> +static void virtballoon_changed(struct virtio_device *vdev)
>> +{
>> + struct virtio_balloon *vb = vdev->priv;
>> + unsigned long flags;
>> + __u32 cmd_id;
>> + s64 diff = towards_target(vb);
>> +
>> + if (diff) {
>> + spin_lock_irqsave(&vb->stop_update_lock, flags);
>> + if (!vb->stop_update)
> Why do you ignore stop_update for freeze?
> This means new wq entries can be added during remove
> causing use after free issues.
I think stop_update isn't needed, because the lock has already been
handled internally by the APIs. Similar examples like
mem_cgroup_css_free() in "mm/memcontrol.c", there is no such locks used
for cancel_work_sync(&memcg->high_work).
Best,
Wei
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WARNING: multiple messages have this Message-ID (diff)
From: Wei Wang <wei.w.wang@intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org,
pbonzini@redhat.com, liliang.opensource@gmail.com,
yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com,
riel@redhat.com
Subject: Re: [PATCH v22 2/3] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ
Date: Fri, 19 Jan 2018 14:24:11 +0800 [thread overview]
Message-ID: <5A618F0B.4090805@intel.com> (raw)
In-Reply-To: <20180117180337-mutt-send-email-mst@kernel.org>
On 01/18/2018 12:44 AM, Michael S. Tsirkin wrote:
> On Wed, Jan 17, 2018 at 01:10:11PM +0800, Wei Wang wrote:
>>
>> +static void virtballoon_changed(struct virtio_device *vdev)
>> +{
>> + struct virtio_balloon *vb = vdev->priv;
>> + unsigned long flags;
>> + __u32 cmd_id;
>> + s64 diff = towards_target(vb);
>> +
>> + if (diff) {
>> + spin_lock_irqsave(&vb->stop_update_lock, flags);
>> + if (!vb->stop_update)
> Why do you ignore stop_update for freeze?
> This means new wq entries can be added during remove
> causing use after free issues.
I think stop_update isn't needed, because the lock has already been
handled internally by the APIs. Similar examples like
mem_cgroup_css_free() in "mm/memcontrol.c", there is no such locks used
for cancel_work_sync(&memcg->high_work).
Best,
Wei
next prev parent reply other threads:[~2018-01-19 6:21 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-17 5:10 [virtio-dev] [PATCH v22 0/3] Virtio-balloon: support free page reporting Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` [virtio-dev] [PATCH v22 1/3] mm: support reporting free page blocks Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` [PATCH v22 2/3] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ Wei Wang
2018-01-17 5:10 ` [virtio-dev] " Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 8:21 ` Pankaj Gupta
2018-01-17 8:21 ` Pankaj Gupta
2018-01-17 8:21 ` Pankaj Gupta
2018-01-17 9:00 ` Wei Wang
2018-01-17 9:00 ` [virtio-dev] " Wei Wang
2018-01-17 9:00 ` Wei Wang
2018-01-17 9:00 ` Wei Wang
2018-01-17 9:27 ` Pankaj Gupta
2018-01-17 9:27 ` Pankaj Gupta
2018-01-17 9:27 ` Pankaj Gupta
2018-01-17 10:47 ` Wei Wang
2018-01-17 10:47 ` [virtio-dev] " Wei Wang
2018-01-17 10:47 ` Wei Wang
2018-01-17 10:47 ` Wei Wang
2018-01-17 16:44 ` [virtio-dev] " Michael S. Tsirkin
2018-01-17 16:44 ` Michael S. Tsirkin
2018-01-17 16:44 ` Michael S. Tsirkin
2018-01-18 13:30 ` Tetsuo Handa
2018-01-18 13:30 ` Tetsuo Handa
2018-01-18 19:09 ` [virtio-dev] " Michael S. Tsirkin
2018-01-18 19:09 ` Michael S. Tsirkin
2018-01-18 19:09 ` Michael S. Tsirkin
2018-01-18 19:09 ` Michael S. Tsirkin
2018-01-18 21:11 ` Tetsuo Handa
2018-01-18 21:11 ` Tetsuo Handa
2018-01-18 22:32 ` [virtio-dev] " Michael S. Tsirkin
2018-01-18 22:32 ` Michael S. Tsirkin
2018-01-18 22:32 ` Michael S. Tsirkin
2018-01-18 22:32 ` Michael S. Tsirkin
2018-01-20 14:23 ` Tetsuo Handa
2018-01-20 14:23 ` Tetsuo Handa
2018-01-19 3:44 ` [virtio-dev] " Wei Wang
2018-01-19 3:44 ` Wei Wang
2018-01-19 3:44 ` Wei Wang
2018-01-19 12:39 ` Michael S. Tsirkin
2018-01-19 12:39 ` [virtio-dev] " Michael S. Tsirkin
2018-01-19 12:39 ` Michael S. Tsirkin
2018-01-19 12:39 ` Michael S. Tsirkin
2018-01-22 11:25 ` [virtio-dev] " Wei Wang
2018-01-22 11:25 ` Wei Wang
2018-01-22 11:25 ` Wei Wang
2018-01-22 11:25 ` Wei Wang
2018-01-24 3:18 ` Wei Wang
2018-01-24 3:18 ` Wei Wang
2018-01-24 3:18 ` Wei Wang
2018-01-24 3:18 ` Wei Wang
2018-01-24 4:31 ` Michael S. Tsirkin
2018-01-24 4:31 ` Michael S. Tsirkin
2018-01-24 4:31 ` Michael S. Tsirkin
2018-01-24 4:31 ` Michael S. Tsirkin
2018-01-24 4:29 ` Michael S. Tsirkin
2018-01-24 4:29 ` Michael S. Tsirkin
2018-01-24 4:29 ` Michael S. Tsirkin
2018-01-24 4:29 ` Michael S. Tsirkin
2018-01-24 11:28 ` Wei Wang
2018-01-24 11:28 ` Wei Wang
2018-01-24 11:28 ` Wei Wang
2018-01-24 11:28 ` Wei Wang
2018-01-19 3:44 ` Wei Wang
2018-01-19 6:24 ` Wei Wang [this message]
2018-01-19 6:24 ` Wei Wang
2018-01-19 6:24 ` Wei Wang
2018-01-19 6:24 ` Wei Wang
2018-01-17 16:44 ` Michael S. Tsirkin
2018-01-17 5:10 ` [PATCH v22 3/3] virtio-balloon: don't report free pages when page poisoning is enabled Wei Wang
2018-01-17 5:10 ` [virtio-dev] " Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-17 5:10 ` Wei Wang
2018-01-18 22:37 ` [virtio-dev] " Michael S. Tsirkin
2018-01-18 22:37 ` Michael S. Tsirkin
2018-01-18 22:37 ` Michael S. Tsirkin
2018-01-18 22:37 ` Michael S. Tsirkin
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