From: Steffen Klassert <steffen.klassert@secunet.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>,
<andrea.parri@amarulasolutions.com>, <boqun.feng@gmail.com>,
<paulmck@linux.ibm.com>, <peterz@infradead.org>,
<linux-arch@vger.kernel.org>, <linux-crypto@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs
Date: Tue, 16 Jul 2019 13:14:10 +0200 [thread overview]
Message-ID: <20190716111410.GN17989@gauss3.secunet.de> (raw)
In-Reply-To: <20190716100447.pdongriwwfxsuajf@gondor.apana.org.au>
On Tue, Jul 16, 2019 at 06:04:47PM +0800, Herbert Xu wrote:
> On Mon, Jul 15, 2019 at 12:10:46PM -0400, Daniel Jordan wrote:
> >
> > I've been wrong before plenty of times, and there's nothing preventing this
> > from being one of those times :) , but in this case I believe what I'm showing
> > is correct.
> >
> > The padata_do_serial call for a given job ensures padata_reorder runs on the
> > CPU that the job hashed to in padata_do_parallel, which is not necessarily the
> > same CPU as the one that padata_do_parallel itself ran on.
>
> You're right. I was taking the comment in the code at face value,
> never trust comments :)
>
> While looking at the code in question, I think it is seriously
> broken. For instance, padata_replace does not deal with async
> crypto at all. It would fail miserably if the underlying async
> crypto held onto references to the old pd.
Hm, yes looks like that.
padata_replace should not call padata_free_pd() as long as the
refcount is not zero. Currenlty padata_flush_queues() will
BUG if there are references left.
Maybe we can fix it if we call padata_free_pd() from
padata_serial_worker() when it sent out the last object.
next prev parent reply other threads:[~2019-07-16 11:14 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-11 22:12 [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Daniel Jordan
2019-07-12 10:06 ` Herbert Xu
2019-07-12 10:10 ` Steffen Klassert
2019-07-12 16:07 ` Daniel Jordan
2019-07-13 5:03 ` Herbert Xu
2019-07-15 16:10 ` Daniel Jordan
2019-07-16 10:04 ` Herbert Xu
2019-07-16 11:14 ` Steffen Klassert [this message]
2019-07-16 12:57 ` [PATCH] padata: Use RCU when fetching pd from do_serial Herbert Xu
2019-07-16 13:09 ` Herbert Xu
2019-07-16 13:23 ` [v2 PATCH] " Herbert Xu
2019-07-17 8:36 ` Steffen Klassert
2019-07-17 8:50 ` Herbert Xu
2019-07-17 8:28 ` [PATCH] " Steffen Klassert
2019-07-17 8:47 ` Herbert Xu
2019-07-17 8:53 ` Steffen Klassert
2019-07-16 13:15 ` Peter Zijlstra
2019-07-16 13:18 ` Herbert Xu
2019-07-16 13:50 ` Peter Zijlstra
2019-07-16 13:52 ` Herbert Xu
2019-07-16 12:53 ` [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Andrea Parri
2019-07-16 13:13 ` Peter Zijlstra
2019-07-16 15:01 ` Herbert Xu
2019-07-16 15:44 ` Daniel Jordan
2019-07-16 16:32 ` [PATCH v2] " Daniel Jordan
2019-07-17 11:11 ` [PATCH] padata: Replace delayed timer with immediate workqueue in padata_reorder Herbert Xu
2019-07-17 18:32 ` Daniel Jordan
2019-07-18 3:31 ` Herbert Xu
2019-07-18 14:27 ` Daniel Jordan
2019-07-18 14:56 ` Herbert Xu
2019-07-18 15:01 ` [v2 PATCH] " Herbert Xu
2019-07-19 14:37 ` Daniel Jordan
2019-07-19 14:55 ` Herbert Xu
2019-07-19 19:04 ` [PATCH] padata: purge get_cpu and reorder_via_wq from padata_do_serial Daniel Jordan
2019-07-26 12:36 ` Herbert Xu
2019-07-19 14:27 ` [PATCH] padata: Replace delayed timer with immediate workqueue in padata_reorder Daniel Jordan
2019-07-17 23:21 ` Daniel Jordan
2019-07-18 3:30 ` Herbert Xu
2019-07-18 14:25 ` Daniel Jordan
2019-07-18 14:49 ` Herbert Xu
2019-07-19 14:21 ` Daniel Jordan
2019-07-18 5:42 ` [PATCH v2] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Herbert Xu
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