Re: + fix-soft-lockup-when-removing-netconsole-module.patch added to -mm tree

[Oleg Nesterov]

Jason Wessel wrote:
>
> The netpoll_cleanup handler can hang the kernel if there is no work in the
> work queue because a call to cancel_rearming_delayed_work() with no work
> goes into an infinite loop.

This should not be true any longer, cancel_rearming_delayed_work() should work
correctly in any case.

Could you please clarify?

> @@ -771,30 +771,32 @@ void netpoll_cleanup(struct netpoll *np)
>
> [...snip...]
>
> +		if (atomic_dec_and_test(&npinfo->refcnt)) {
> +			skb_queue_purge(&npinfo->arp_tx);
> +			skb_queue_purge(&npinfo->txq);
> +			if (delayed_work_pending(&npinfo->tx_work)) {
>  				cancel_rearming_delayed_work(&npinfo->tx_work);
>  				flush_scheduled_work();

But this "if (delayed_work_pending())" is racy anyway?

Oleg.

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