[Qemu-devel] Re: [PULL] vhost,e1000 fixes

[Blue Swirl]

On Mon, Sep 20, 2010 at 7:21 PM, Michael S. Tsirkin <address@hidden> wrote:
> On Mon, Sep 20, 2010 at 06:23:55PM +0000, Blue Swirl wrote:
>> On Mon, Sep 20, 2010 at 6:08 PM, Michael S. Tsirkin <address@hidden> wrote:
>> > This fixes a bug in vhost error handling
>> > (also triggers build warning with vhost enabled)
>> > and fixes e1000 handling of short frames.
>> >
>> > Discussion on best ways to fix the e1000 issue
>> > is still ongoing but the  bug is severe enough
>> > for some guests and the fix is safe enough
>> > that I feel we should have it fixed ASAP
>> > and look for that perfect approach later.
>> >
>> > Both fixes are 0.13 material IMO.
>> >
>> > The following changes since commit 
>> > 952afb719f3c965bae12b5bd5f0f0f7ed0251cb8:
>> >
>> >  mingw: use ASLR, no-SEH and DEP if available (2010-09-19 08:36:34 +0000)
>> >
>> > are available in the git repository at:
>> >  git://git.kernel.org/pub/scm/linux/kernel/git/mst/qemu.git for_anthony
>> >
>> > Michael S. Tsirkin (1):
>> >      vhost: fix infinite loop on error path
>>
>> I don't think your fix is correct either, it will call the ioctl()
>> with file.index == -1.
>
> This is my patch:
>
> -    while (--file.index >= 0) {
> +    while (file.index-- > 0) {
>         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
>         assert(r >= 0);
>     }
>
> For ioctl to get called with -1, index needs to be 0
> before the decrement, and while won't be entered ...
> what am I missing?

Then ioctl() won't be called at all. Is that correct?