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X-Bullshit: proxy-oriented base full-stack replication 
Subject: Re: [9front] fix race condition on writes to #v/vgactl
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Quoth qwx@sciops.net:
>  	case CMdrawinit:
> -		if(scr->gscreen == nil)
> +		canqlock(&drawlock);
> +		if(scr->gscreen == nil){
> +			qunlock(&drawlock);
>  			error(Enoscreen);
> +		}

this canqlock without an if looks supsicious to me;
if someone else holds the lock, the canqlock fails,
but that means we unlock *someone elses* lock.