From: Segher Boessenkool <segher@kernel.crashing.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/2] powerpc/32: add stack protector support
Date: Fri, 28 Sep 2018 11:26:25 -0500 [thread overview]
Message-ID: <20180928162625.GT23155@gate.crashing.org> (raw)
In-Reply-To: <8736ttu6fs.fsf@concordia.ellerman.id.au>
On Fri, Sep 28, 2018 at 10:56:07PM +1000, Michael Ellerman wrote:
> The problem of low entropy at boot on systems without a good hardware
> source is sort of unsolvable.
>
> As you say it's up to the core kernel/random code, we shouldn't be
> trying to do anything tricky in the arch code.
>
> You don't want your system to take 3 hours to boot because it's waiting
> for entropy for the stack canary.
>
> If we can update the canary later once the entropy pool is setup that
> would be ideal.
Yup, I agree with all that.
But we should *also* not say "oh, there may be cases where we cannot
do the right thing, so just do not even try, ever, anywhere".
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe LEROY <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/2] powerpc/32: add stack protector support
Date: Fri, 28 Sep 2018 11:26:25 -0500 [thread overview]
Message-ID: <20180928162625.GT23155@gate.crashing.org> (raw)
In-Reply-To: <8736ttu6fs.fsf@concordia.ellerman.id.au>
On Fri, Sep 28, 2018 at 10:56:07PM +1000, Michael Ellerman wrote:
> The problem of low entropy at boot on systems without a good hardware
> source is sort of unsolvable.
>
> As you say it's up to the core kernel/random code, we shouldn't be
> trying to do anything tricky in the arch code.
>
> You don't want your system to take 3 hours to boot because it's waiting
> for entropy for the stack canary.
>
> If we can update the canary later once the entropy pool is setup that
> would be ideal.
Yup, I agree with all that.
But we should *also* not say "oh, there may be cases where we cannot
do the right thing, so just do not even try, ever, anywhere".
Segher
next prev parent reply other threads:[~2018-09-28 16:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 11:40 [PATCH v4 1/2] powerpc/32: add stack protector support Christophe Leroy
2018-09-26 11:40 ` [PATCH v4 2/2] powerpc/64: " Christophe Leroy
2018-09-26 19:16 ` [PATCH v4 1/2] powerpc/32: " Segher Boessenkool
2018-09-27 6:20 ` Christophe LEROY
2018-09-27 7:45 ` Segher Boessenkool
2018-09-27 11:51 ` Christophe LEROY
2018-09-28 12:56 ` Michael Ellerman
2018-09-28 12:56 ` Michael Ellerman
2018-09-28 16:26 ` Segher Boessenkool [this message]
2018-09-28 16:26 ` Segher Boessenkool
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