From: Jie Deng <jie.deng@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>,
Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Wolfram Sang <wsa@kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kernel <kernel@axis.com>
Subject: Re: [PATCH 1/2] i2c: virtio: disable timeout handling
Date: Thu, 21 Oct 2021 11:30:28 +0800 [thread overview]
Message-ID: <df7e6127-05fb-6aad-3896-fc810f213a54@intel.com> (raw)
In-Reply-To: <20211020110316.4x7tnxonswjuuoiw@vireshk-i7>
On 2021/10/20 19:03, Viresh Kumar wrote:
> On 20-10-21, 12:55, Vincent Whitchurch wrote:
>> If the timeout cannot be disabled, then the driver should be fixed to
>> always copy buffers and hold on to them to avoid memory corruption in
>> the case of timeout, as I mentioned in my commit message. That would be
>> quite a substantial change to the driver so it's not something I'm
>> personally comfortable with doing, especially not this late in the -rc
>> cycle, so I'd leave that to others.
> Or we can avoid clearing up and freeing the buffers here until the
> point where the buffers are returned by the host. Until that happens,
> we can avoid taking new requests but return to the earlier caller with
> timeout failure. That would avoid corruption, by freeing buffers
> sooner, and not hanging of the kernel.
It seems similar to use "wait_for_completion". If the other side is
hacked, the guest may never
get the buffers returned by the host, right ?
For this moment, we can solve the problem by using a hardcoded big value
or disabling the timeout.
Over the long term, I think the backend should provide that timeout
value and guarantee that its processing
time should not exceed that value.
WARNING: multiple messages have this Message-ID (diff)
From: Jie Deng <jie.deng@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>,
Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
Wolfram Sang <wsa@kernel.org>, kernel <kernel@axis.com>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Subject: Re: [PATCH 1/2] i2c: virtio: disable timeout handling
Date: Thu, 21 Oct 2021 11:30:28 +0800 [thread overview]
Message-ID: <df7e6127-05fb-6aad-3896-fc810f213a54@intel.com> (raw)
In-Reply-To: <20211020110316.4x7tnxonswjuuoiw@vireshk-i7>
On 2021/10/20 19:03, Viresh Kumar wrote:
> On 20-10-21, 12:55, Vincent Whitchurch wrote:
>> If the timeout cannot be disabled, then the driver should be fixed to
>> always copy buffers and hold on to them to avoid memory corruption in
>> the case of timeout, as I mentioned in my commit message. That would be
>> quite a substantial change to the driver so it's not something I'm
>> personally comfortable with doing, especially not this late in the -rc
>> cycle, so I'd leave that to others.
> Or we can avoid clearing up and freeing the buffers here until the
> point where the buffers are returned by the host. Until that happens,
> we can avoid taking new requests but return to the earlier caller with
> timeout failure. That would avoid corruption, by freeing buffers
> sooner, and not hanging of the kernel.
It seems similar to use "wait_for_completion". If the other side is
hacked, the guest may never
get the buffers returned by the host, right ?
For this moment, we can solve the problem by using a hardcoded big value
or disabling the timeout.
Over the long term, I think the backend should provide that timeout
value and guarantee that its processing
time should not exceed that value.
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Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-10-21 3:30 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 7:46 [PATCH 0/2] virtio-i2c: Fix buffer handling Vincent Whitchurch
2021-10-19 7:46 ` Vincent Whitchurch
2021-10-19 7:46 ` [PATCH 1/2] i2c: virtio: disable timeout handling Vincent Whitchurch
2021-10-19 7:46 ` Vincent Whitchurch
2021-10-19 8:09 ` Viresh Kumar
2021-10-19 8:09 ` Viresh Kumar
2021-10-19 9:36 ` Greg KH
2021-10-19 9:36 ` Greg KH
2021-10-19 9:42 ` Viresh Kumar
2021-10-19 9:42 ` Viresh Kumar
2021-10-19 11:15 ` Wolfram Sang
2021-10-19 14:14 ` Viresh Kumar
2021-10-19 14:14 ` Viresh Kumar
2021-10-19 11:16 ` Greg KH
2021-10-19 11:16 ` Greg KH
2021-10-19 14:37 ` Viresh Kumar
2021-10-19 14:37 ` Viresh Kumar
2021-10-19 18:14 ` Wolfram Sang
2021-10-20 4:20 ` Jie Deng
2021-10-20 4:20 ` Jie Deng
2021-10-20 5:36 ` Greg KH
2021-10-20 5:36 ` Greg KH
2021-10-20 6:35 ` Jie Deng
2021-10-20 6:35 ` Jie Deng
2021-10-20 6:41 ` Viresh Kumar
2021-10-20 6:41 ` Viresh Kumar
2021-10-20 7:04 ` Jie Deng
2021-10-20 7:04 ` Jie Deng
2021-10-20 10:55 ` Vincent Whitchurch
2021-10-20 10:55 ` Vincent Whitchurch
2021-10-20 11:03 ` Viresh Kumar
2021-10-20 11:03 ` Viresh Kumar
2021-10-21 3:30 ` Jie Deng [this message]
2021-10-21 3:30 ` Jie Deng
2021-10-29 12:24 ` Vincent Whitchurch
2021-10-29 12:24 ` Vincent Whitchurch
2021-11-01 5:23 ` Jie Deng
2021-11-01 5:23 ` Jie Deng
2021-11-03 6:18 ` Chen, Conghui
2021-11-03 6:37 ` Viresh Kumar
2021-11-03 6:37 ` Viresh Kumar
2021-11-03 14:42 ` Vincent Whitchurch
2021-11-03 14:42 ` Vincent Whitchurch
2021-11-09 4:52 ` Viresh Kumar
2021-11-09 4:52 ` Viresh Kumar
2021-10-20 3:36 ` Jie Deng
2021-10-20 3:36 ` Jie Deng
2021-10-19 7:46 ` [PATCH 2/2] i2c: virtio: fix completion handling Vincent Whitchurch
2021-10-19 7:46 ` Vincent Whitchurch
2021-10-19 8:22 ` Viresh Kumar
2021-10-19 8:22 ` Viresh Kumar
2021-10-20 8:54 ` Jie Deng
2021-10-20 8:54 ` Jie Deng
2021-10-20 9:17 ` Viresh Kumar
2021-10-20 9:17 ` Viresh Kumar
2021-10-20 10:38 ` Vincent Whitchurch
2021-10-20 10:38 ` Vincent Whitchurch
2021-10-20 10:47 ` Viresh Kumar
2021-10-20 10:47 ` Viresh Kumar
2021-10-29 11:54 ` Vincent Whitchurch
2021-10-29 11:54 ` Vincent Whitchurch
2021-10-21 5:55 ` Jie Deng
2021-10-21 5:55 ` Jie Deng
2021-10-21 5:58 ` Viresh Kumar
2021-10-21 5:58 ` Viresh Kumar
2021-11-02 4:32 ` Viresh Kumar
2021-11-02 4:32 ` Viresh Kumar
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