Re: [PATCH] xen-netfront: Improve error handling during initialization

On 02/02/2017 09:54 AM, Ross Lagerwall wrote:

On 02/01/2017 06:54 PM, Boris Ostrovsky wrote:

quoted

On 02/01/2017 10:50 AM, Ross Lagerwall wrote:

quoted

Improve error handling during initialization. This fixes a crash when
running out of grant refs when creating many queues across many
netdevs.

* Delay timer creation so that if initializing a queue fails, the timer
has not been setup yet.
* If creating queues fails (i.e. there are no grant refs available),
call xenbus_dev_fatal() to ensure that the xenbus device is set to the
closed state.
* If no queues are created, don't call xennet_disconnect_backend as
netdev->real_num_tx_queues will not have been set correctly.
* If setup_netfront() fails, ensure that all the queues created are
cleaned up, not just those that have been set up.
* If any queues were set up and an error occurs, call
xennet_destroy_queues() to stop the timer and clean up the napi
context.

We need to stop the timer in xennet_disconnect_backend(). I sent a patch
a couple of day ago

https://lists.xenproject.org/archives/html/xen-devel/2017-01/msg03269.html


but was about to resend it with del_timer_sync() moved after
napi_synchronize().

OK, but the patch is still relevant since I believe we still need to
clean up the napi context in this case (plus the patch fixes a lot of
other issues).

I was only commenting on that specific bullet in the commit message, I
am not arguing against the patch.

But I will respin it on top of your patch(es) and re-test it before
resending.

You can re-test with the patch in the link above, I will not be
re-sending new version.

Thanks.
-boris




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