From: Michael Ellerman <mpe@ellerman.id.au>
To: Laurent Vivier <lvivier@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
dgibson@redhat.com, thuth@redhat.com
Subject: Re: [PATCH] powerpc: on crash, kexec'ed kernel needs all CPUs are online
Date: Fri, 16 Oct 2015 13:14:50 +1100 [thread overview]
Message-ID: <1444961690.28419.1.camel@ellerman.id.au> (raw)
In-Reply-To: <1444935658-27319-1-git-send-email-lvivier@redhat.com>
On Thu, 2015-10-15 at 21:00 +0200, Laurent Vivier wrote:
> On kexec, all secondary offline CPUs are onlined before
> starting the new kernel, this is not done in the case of kdump.
>
> If kdump is configured and a kernel crash occurs whereas
> some secondaries CPUs are offline (SMT=off),
> the new kernel is not able to start them and displays some
> "Processor X is stuck.".
Do we know why they are stuck?
I really don't like this fix. The reason we're doing a kdump is because the
first kernel has panicked, possibly with locks held or data structures
corrupted. Calling cpu_up() then goes and tries to run a bunch of code in the
crashed kernel, which increases the chance of us just wedging completely.
cheers
next prev parent reply other threads:[~2015-10-16 2:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-15 19:00 [PATCH] powerpc: on crash, kexec'ed kernel needs all CPUs are online Laurent Vivier
2015-10-16 0:27 ` kbuild test robot
2015-10-16 2:14 ` Michael Ellerman [this message]
2015-10-16 7:48 ` Laurent Vivier
2015-10-17 2:01 ` Benjamin Herrenschmidt
2015-10-16 2:29 ` David Gibson
2015-10-16 7:57 ` Laurent Vivier
2015-10-17 2:03 ` Benjamin Herrenschmidt
2015-11-04 12:34 ` Hari Bathini
2015-11-04 13:54 ` Laurent Vivier
2015-11-05 1:32 ` David Gibson
2015-11-05 6:59 ` Stewart Smith
2015-11-05 10:23 ` Hari Bathini
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