Re: [Xen-devel] [BUG] race condition in blkfront (probably other frontends too).

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 24/7/08 15:15, "Gerd Hoffmann" <kraxel@xxxxxxxxxx> wrote:

> I've just seen it with the block frontend, but most likely the other
> frontend drivers are affected too.  The blkfront drivers goes into
> initialized state (in blkfront_probe), and *after* that xenbus_dev_probe
> sets a watch on the state node of the device.  That leaves a race window
> open for the backend going into connected state before the watch is
> active.  If that happens the frontend doesn't notice the backend is
> ready and never ever goes into connected state ...

xenstored fires a watch immediately when it is registered. That should deal
with this particular race. Unless the watch gets discarded at the top of
otherend_changed() for some reason? I think you need to delve into this
issue a bit more, I'm afraid.

 -- Keir



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