From: Segher Boessenkool <segher@kernel.crashing.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: "linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>,
Gautham R Shenoy <ego@linux.vnet.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>,
Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Subject: Re: Stack protector crash in pnv_smp_cpu_kill_self()
Date: Tue, 16 Oct 2018 09:23:41 -0500 [thread overview]
Message-ID: <20181016142340.GY29268@gate.crashing.org> (raw)
In-Reply-To: <87ftx6kowh.fsf@concordia.ellerman.id.au>
On Wed, Oct 17, 2018 at 12:21:50AM +1100, Michael Ellerman wrote:
> Christophe LEROY <christophe.leroy@c-s.fr> writes:
>
> > Looks like a lack of initialisation of the canary for the non-boot CPUs
> > on SMP, you applied this morning the patch I sent you for that.
> >
> > Is the patch in ?
>
> Yeah it is.
>
> $ git log --oneline 4ffe713b7587 arch/powerpc/kernel/smp.c
> 8e8a31d7fd54 powerpc: Use cpu_smallcore_sibling_mask at SMT level on bigcores
> 425752c63b6f powerpc: Detect the presence of big-cores via "ibm, thread-groups"
> 7241d26e8175 powerpc/64: properly initialise the stackprotector canary on SMP.
>
>
> It only happens on a specific Power9 machine, not in sim, but it's 100%
> reproducible on that hardware.
>
> The canary value has changed (?!).
>
> The value in paca->canary and current->canary agree, but they don't
> match what's in the stack.
>
> Clearly the idle code is doing something I don't understand :)
Did something actually corrupt the stack?
Segher
prev parent reply other threads:[~2018-10-16 14:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 13:26 Stack protector crash in pnv_smp_cpu_kill_self() Michael Ellerman
2018-10-15 13:29 ` Christophe LEROY
2018-10-16 13:21 ` Michael Ellerman
2018-10-16 14:23 ` Segher Boessenkool [this message]
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