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Date:   Sun, 6 Dec 2020 22:40:53 +0100
From:   Corentin Labbe <clabbe.montjoie@gmail.com>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     herbert@gondor.apana.org.au, mripard@kernel.org, wens@csie.org,
        linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
        linux-mm@kvack.org, Andrew Morton <akpm@linuxfoundation.org>,
        Julia Lawall <julia.lawall@lip6.fr>
Subject: Re: crypto: sun4i-ss: error with kmap
Message-ID: <20201206214053.GA8458@Red>
References: <20201202195501.GA29296@Red>
 <877dpzexfr.fsf@nanos.tec.linutronix.de>
 <20201203173846.GA16207@Red>
 <87r1o6bh1u.fsf@nanos.tec.linutronix.de>
 <20201204132631.GA25321@Red>
 <874kl1bod0.fsf@nanos.tec.linutronix.de>
 <20201204192753.GA19782@Red>
 <87wnxx9tle.fsf@nanos.tec.linutronix.de>
 <20201205184334.GA8034@Red>
 <87mtys8268.fsf@nanos.tec.linutronix.de>
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On Sat, Dec 05, 2020 at 08:48:15PM +0100, Thomas Gleixner wrote:
> Corentin,
> 
> On Sat, Dec 05 2020 at 19:43, Corentin Labbe wrote:
> > On Fri, Dec 04, 2020 at 09:58:21PM +0100, Thomas Gleixner wrote:
> >> Can you please replace the debug patch with the one below and try again?
> >> That stops the trace right on the condition.
> >
> > Hello, the result could be found at http://kernel.montjoie.ovh/130739.log
> 
> Thanks for providing this. This is clearly showing where stuff goes
> wrong. It starts here at 729.550001. I removed the uninteresting parts:
> 
> 0d..2 147103293us : __kmap_local_page_prot <-sg_miter_next
> 0d..3 147103308us :__kmap_local_pfn_prot: kmap_local_pfn: 1 ffefd000
> 
> 0d..3 147103311us : __kmap_local_page_prot <-sg_miter_next
> 0d..4 147103325us : __kmap_local_pfn_prot: kmap_local_pfn: 3 ffefb000
> 
> 0d..3 147103429us : kunmap_local_indexed <-sg_miter_stop
> 0d..4 147103433us : kunmap_local_indexed: kunmap_local: 3 ffefd000
> 
> So this maps two pages and unmaps the first one. That's all called from
> sun4i_ss_opti_poll() and the bug is clearly visible there:
> 
> 	sg_miter_next(&mi);
> 	sg_miter_next(&mo);
> 
> release_ss:
> 	sg_miter_stop(&mi);
> 	sg_miter_stop(&mo);
> 
> Written by yourself :) Same issue in sun4i_ss_cipher_poll()
> 
> Fix below.
> 

Unfortunatly, the crash still happen with the fix.
See http://kernel.montjoie.ovh/131321.log