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Subject: Re: [-next] system hangs likely due to "modules: Only return -EEXIST
 for modules that have finished loading"
To:     Heiko Carstens <heiko.carstens@de.ibm.com>
Cc:     Jessica Yu <jeyu@kernel.org>, linux-next@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
        Cathy Avery <cavery@redhat.com>
References: <20190426130736.GB8646@osiris>
 <d4d75ad1-e193-c230-1edc-a93db2b068d7@redhat.com>
 <20190426150741.GD8646@osiris> <20190426160956.GA3827@linux-8ccs>
 <2e047a7e-bf08-be8c-bdd0-429464fa133d@redhat.com>
 <52c293e9-ddfa-426a-a8f1-2106e250e78d@redhat.com>
 <f74996cb-3e0a-ab23-00b9-85ac782583d1@redhat.com>
 <20190427102440.GA28889@osiris>
From:   Prarit Bhargava <prarit@redhat.com>
Message-ID: <6a69074a-e913-3b67-feef-9b62a7400f8a@redhat.com>
Date:   Sat, 27 Apr 2019 06:42:51 -0400
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On 4/27/19 6:24 AM, Heiko Carstens wrote:

> 
> diff --git a/kernel/module.c b/kernel/module.c
> index 410eeb7e4f1d..48748cfec991 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3585,6 +3585,7 @@ again:
>  					       finished_loading(mod->name));
>  			if (err)
>  				goto out_unlocked;
> +			cond_resched();
>  			goto again;
>  		}
>  		err = -EEXIST;
> 

Heiko, I'm testing on 2-cpu systems which appear to show the problem ~10% of the
time.  On another system I backed out my original patch to set a baseline, and
noticed that occasionally the time to boot the system doubles from ~4 seconds to
9 seconds.  Is this something you're also concerned with?

P.