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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com,
	kvm@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use
Date: Tue, 8 Mar 2022 06:05:24 -0500	[thread overview]
Message-ID: <20220308060210-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <Yicalf1I6oBytbse@kroah.com>

On Tue, Mar 08, 2022 at 09:57:57AM +0100, Greg KH wrote:
> > > And what happens if the mutex is locked _RIGHT_ after you checked it?
> > > You still have a race...
> > 
> > No, we miss a warning that one time.  Memory is still protected.
> 
> Then don't warn on something that doesn't matter.  This line can be
> dropped as there's nothing anyone can do about it, right?

I mean, the reason I wanted the warning is because there's a kernel
bug, and it will break userspace. warning is just telling us this.
is the bug reacheable from userspace? if we knew that we won't
need the lock ...

-- 
MST

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Virtualization@lists.linux-foundation.org
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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Lee Jones <lee.jones@linaro.org>,
	jasowang@redhat.com, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, stable@vger.kernel.org,
	syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com
Subject: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use
Date: Tue, 8 Mar 2022 06:05:24 -0500	[thread overview]
Message-ID: <20220308060210-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <Yicalf1I6oBytbse@kroah.com>

On Tue, Mar 08, 2022 at 09:57:57AM +0100, Greg KH wrote:
> > > And what happens if the mutex is locked _RIGHT_ after you checked it?
> > > You still have a race...
> > 
> > No, we miss a warning that one time.  Memory is still protected.
> 
> Then don't warn on something that doesn't matter.  This line can be
> dropped as there's nothing anyone can do about it, right?

I mean, the reason I wanted the warning is because there's a kernel
bug, and it will break userspace. warning is just telling us this.
is the bug reacheable from userspace? if we knew that we won't
need the lock ...

-- 
MST


  parent reply	other threads:[~2022-03-08 11:05 UTC|newest]

Thread overview: 94+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-07 19:17 [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Lee Jones
2022-03-07 19:17 ` Lee Jones
2022-03-07 19:33 ` Greg KH
2022-03-07 19:33   ` Greg KH
2022-03-07 22:39   ` Michael S. Tsirkin
2022-03-07 22:39     ` Michael S. Tsirkin
2022-03-08  8:10   ` Lee Jones
2022-03-08  8:10     ` Lee Jones
2022-03-08  8:11     ` Lee Jones
2022-03-08  8:11       ` Lee Jones
2022-03-08  8:57     ` Greg KH
2022-03-08  8:57       ` Greg KH
2022-03-08  9:15       ` Lee Jones
2022-03-08  9:15         ` Lee Jones
2022-03-08  9:57         ` Greg KH
2022-03-08  9:57           ` Greg KH
2022-03-08 10:08           ` Lee Jones
2022-03-08 10:08             ` Lee Jones
2022-03-08 10:55           ` Michael S. Tsirkin
2022-03-08 10:55             ` Michael S. Tsirkin
2022-03-08 11:45             ` Greg KH
2022-03-08 11:45               ` Greg KH
2022-03-08 12:27               ` Michael S. Tsirkin
2022-03-08 12:27                 ` Michael S. Tsirkin
2022-03-08 13:17                 ` Lee Jones
2022-03-08 13:17                   ` Lee Jones
2022-03-08 17:17                   ` Michael S. Tsirkin
2022-03-08 17:17                     ` Michael S. Tsirkin
2022-03-08 11:05       ` Michael S. Tsirkin [this message]
2022-03-08 11:05         ` Michael S. Tsirkin
2022-03-09 18:52       ` Leon Romanovsky
2022-03-09 18:52         ` Leon Romanovsky
2022-03-07 22:37 ` Michael S. Tsirkin
2022-03-07 22:37   ` Michael S. Tsirkin
2022-03-08  8:01   ` Lee Jones
2022-03-08  8:01     ` Lee Jones
2022-03-08 11:07     ` Michael S. Tsirkin
2022-03-08 11:07       ` Michael S. Tsirkin
2022-03-08  6:15 ` Jason Wang
2022-03-08  6:15   ` Jason Wang
2022-03-08  8:08   ` Lee Jones
2022-03-08  8:08     ` Lee Jones
2022-03-08 11:06     ` Michael S. Tsirkin
2022-03-08 11:06       ` Michael S. Tsirkin
  -- strict thread matches above, loose matches on Subject: below --
2022-03-14  8:43 Lee Jones
2022-03-14  8:43 ` Lee Jones
2022-03-14  8:56 ` Greg KH
2022-03-14  8:56   ` Greg KH
2022-03-14 11:49 ` Michael S. Tsirkin
2022-03-14 11:49   ` Michael S. Tsirkin
2022-03-14 12:47   ` Lee Jones
2022-03-14 12:47     ` Lee Jones
2022-03-02  7:54 Lee Jones
2022-03-02  7:54 ` Lee Jones
2022-03-02  9:34 ` Stefano Garzarella
2022-03-02  9:34   ` Stefano Garzarella
2022-03-02 10:07   ` Lee Jones
2022-03-02 10:07     ` Lee Jones
2022-03-02 13:35   ` Michael S. Tsirkin
2022-03-02 13:35     ` Michael S. Tsirkin
2022-03-02 14:11     ` Stefano Garzarella
2022-03-02 14:11       ` Stefano Garzarella
2022-03-02 14:50       ` Michael S. Tsirkin
2022-03-02 14:50         ` Michael S. Tsirkin
2022-03-02 15:36         ` Stefano Garzarella
2022-03-02 15:36           ` Stefano Garzarella
2022-03-04 16:46           ` Michael S. Tsirkin
2022-03-04 16:46             ` Michael S. Tsirkin
2022-03-02 13:30 ` Michael S. Tsirkin
2022-03-02 13:30   ` Michael S. Tsirkin
2022-03-02 13:56   ` Lee Jones
2022-03-02 13:56     ` Lee Jones
2022-03-02 14:51     ` Michael S. Tsirkin
2022-03-02 14:51       ` Michael S. Tsirkin
2022-03-02 14:57       ` Lee Jones
2022-03-02 14:57         ` Lee Jones
2022-03-02 16:28         ` Stefano Garzarella
2022-03-02 16:28           ` Stefano Garzarella
2022-03-02 16:30           ` Michael S. Tsirkin
2022-03-02 16:30             ` Michael S. Tsirkin
2022-03-02 16:49             ` Lee Jones
2022-03-02 16:49               ` Lee Jones
2022-03-02 17:10               ` Stefano Garzarella
2022-03-02 17:10                 ` Stefano Garzarella
2022-03-03 14:17                 ` Lee Jones
2022-03-03 14:17                   ` Lee Jones
2022-03-04  5:00 ` Michael S. Tsirkin
2022-03-04  5:00   ` Michael S. Tsirkin
2022-03-04 15:22   ` Lee Jones
2022-03-04 15:22     ` Lee Jones
2022-03-04 16:48 ` Michael S. Tsirkin
2022-03-04 16:48   ` Michael S. Tsirkin
2022-03-04 16:56   ` Lee Jones
2022-03-04 16:56     ` Lee Jones

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