From: Megha Dey <megha.dey@linux.intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: SHA1-MB algorithm broken on latest kernel
Date: Fri, 13 May 2016 10:32:26 -0700 [thread overview]
Message-ID: <1463160746.2594.11.camel@megha-Z97X-UD7-TH> (raw)
In-Reply-To: <20160513055103.GB24504@gmail.com>
On Fri, 2016-05-13 at 07:51 +0200, Ingo Molnar wrote:
> * Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> > On Thu, May 12, 2016 at 04:31:06PM -0700, Megha Dey wrote:
> > > Hi,
> > >
> > > When booting latest kernel with the CONFIG_CRYPTO_SHA1_MB enabled, I
> > > observe a panic.
> > >
> > > After having a quick look, on reverting the following patches, I am able
> > > to complete the booting process.
> > > aec4d0e301f17bb143341c82cc44685b8af0b945
> > > 8691ccd764f9ecc69a6812dfe76214c86ac9ba06
> > > 68874ac3304ade7ed5ebb12af00d6b9bbbca0a16
> > >
> > > Of the 3 patches, aec4d0e301f17bb143341c82cc44685b8af0b945 seems wrong.
> > > The r10 to r15 registers are used in sha1_x8_avx2.S, which is called
> > > from sha1_mb_mgr_flush_avx2.S.
> > >
> > > I do not think the functionality of the SHA1-MB crypto algorithm has
> > > been tested after applying these changes. (I am not sure if any of the
> > > other crypto algorithms have been affected by these changes).
> >
> > Josh, Ingo:
> >
> > Any ideas on this? Should we revert?
>
> Yeah, I think so - although another option would be to standardize sha1_x8_avx2()
> - the problem is that it is a function that clobbers registers without
> saving/restoring them, breaking the C function ABI. I realize it's written in
> assembly, but unless there are strong performance reasons to deviate from the
> regular calling convention it might make sense to fix that.
>
> Do any warnings get generated after the revert, if you enable
> CONFIG_STACK_VALIDATION=y?
After the revert and enabling CONFIG_STACK_VALIDATION:
arch/x86/crypto/sha1-mb/sha1_mb_mgr_flush_avx2.o: warning: objtool:
sha1_mb_mgr_flush_avx2()+0x20d: call without frame pointer save/setup
arch/x86/crypto/sha1-mb/sha1_mb_mgr_submit_avx2.o: warning: objtool:
sha1_mb_mgr_submit_avx2()+0x115: call without frame pointer save/setup
>
> Thanks,
>
> Ingo
next prev parent reply other threads:[~2016-05-13 17:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-12 23:31 SHA1-MB algorithm broken on latest kernel Megha Dey
2016-05-13 3:10 ` Herbert Xu
2016-05-13 5:51 ` Ingo Molnar
2016-05-13 17:32 ` Megha Dey [this message]
2016-05-16 14:44 ` Josh Poimboeuf
2016-05-16 18:31 ` Megha Dey
2016-05-16 20:16 ` [PATCH] crypto/sha1-mb: make sha1_x8_avx2() conform to C function ABI Josh Poimboeuf
2016-05-16 21:39 ` Megha Dey
2016-05-16 21:46 ` Josh Poimboeuf
2016-05-16 23:07 ` Megha Dey
2016-05-17 6:31 ` Herbert Xu
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