From: Wolfram Sang <wsa@kernel.org>
To: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: jie.deng@intel.com, viresh.kumar@linaro.org,
conghui.chen@intel.com, mst@redhat.com,
virtualization@lists.linux-foundation.org,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel@axis.com
Subject: Re: [PATCH v2 1/2] i2c: virtio: disable timeout handling
Date: Tue, 23 Nov 2021 10:52:05 +0100 [thread overview]
Message-ID: <YZy5xVU4XHEaz+EL@kunai> (raw)
In-Reply-To: <20211111160412.11980-2-vincent.whitchurch@axis.com>
[-- Attachment #1: Type: text/plain, Size: 1632 bytes --]
On Thu, Nov 11, 2021 at 05:04:11PM +0100, Vincent Whitchurch wrote:
> If a timeout is hit, it can result is incorrect data on the I2C bus
> and/or memory corruptions in the guest since the device can still be
> operating on the buffers it was given while the guest has freed them.
>
> Here is, for example, the start of a slub_debug splat which was
> triggered on the next transfer after one transfer was forced to timeout
> by setting a breakpoint in the backend (rust-vmm/vhost-device):
>
> BUG kmalloc-1k (Not tainted): Poison overwritten
> First byte 0x1 instead of 0x6b
> Allocated in virtio_i2c_xfer+0x65/0x35c age=350 cpu=0 pid=29
> __kmalloc+0xc2/0x1c9
> virtio_i2c_xfer+0x65/0x35c
> __i2c_transfer+0x429/0x57d
> i2c_transfer+0x115/0x134
> i2cdev_ioctl_rdwr+0x16a/0x1de
> i2cdev_ioctl+0x247/0x2ed
> vfs_ioctl+0x21/0x30
> sys_ioctl+0xb18/0xb41
> Freed in virtio_i2c_xfer+0x32e/0x35c age=244 cpu=0 pid=29
> kfree+0x1bd/0x1cc
> virtio_i2c_xfer+0x32e/0x35c
> __i2c_transfer+0x429/0x57d
> i2c_transfer+0x115/0x134
> i2cdev_ioctl_rdwr+0x16a/0x1de
> i2cdev_ioctl+0x247/0x2ed
> vfs_ioctl+0x21/0x30
> sys_ioctl+0xb18/0xb41
>
> There is no simple fix for this (the driver would have to always create
> bounce buffers and hold on to them until the device eventually returns
> the buffers), so just disable the timeout support for now.
>
> Fixes: 3cfc88380413d20f ("i2c: virtio: add a virtio i2c frontend driver")
> Acked-by: Jie Deng <jie.deng@intel.com>
> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Applied to for-current, thanks!
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2021-11-23 9:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-11 16:04 [PATCH v2 0/2] virtio-i2c: Fix buffer handling Vincent Whitchurch
2021-11-11 16:04 ` [PATCH v2 1/2] i2c: virtio: disable timeout handling Vincent Whitchurch
2021-11-11 16:46 ` Michael S. Tsirkin
2021-11-12 2:35 ` Viresh Kumar
2021-11-19 15:30 ` Vincent Whitchurch
2021-11-23 9:52 ` Wolfram Sang [this message]
2021-11-23 9:54 ` Viresh Kumar
2021-11-23 9:55 ` Wolfram Sang
2021-11-11 16:04 ` [PATCH v2 2/2] i2c: virtio: fix completion handling Vincent Whitchurch
2021-11-11 16:57 ` Michael S. Tsirkin
2021-12-02 15:34 ` Vincent Whitchurch
2021-11-24 23:55 ` [PATCH v2 0/2] virtio-i2c: Fix buffer handling Michael S. Tsirkin
2021-11-25 3:21 ` Viresh Kumar
2021-11-25 6:24 ` Wolfram Sang
2021-11-25 6:47 ` Viresh Kumar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YZy5xVU4XHEaz+EL@kunai \
--to=wsa@kernel.org \
--cc=conghui.chen@intel.com \
--cc=jie.deng@intel.com \
--cc=kernel@axis.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=vincent.whitchurch@axis.com \
--cc=viresh.kumar@linaro.org \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).