From: "Michal Suchánek" <msuchanek@suse.de>
To: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
harshpb@linux.ibm.com, Gautam Menghani <gautam@linux.ibm.com>,
amachhiw@linux.ibm.com,
Christian Zigotzky <chzigotzky@xenosoft.de>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
"R.T.Dickinson" <rtd2@xtra.co.nz>,
hypexed@yahoo.com.au, mad skateman <madskateman@gmail.com>,
Christian Zigotzky <info@xenosoft.de>,
Samir M <samir@linux.ibm.com>,
Venkat Rao Bagalkote <venkat88@linux.ibm.com>,
Narayana Murty N <nnmlinux@linux.ibm.com>,
Hari Bathini <hbathini@linux.ibm.com>
Subject: Re: [Linux PPC] Disable PREEMPT
Date: Fri, 18 Sep 2026 13:52:14 +0200 [thread overview]
Message-ID: <aq0l7k7d-eCJCXQZ@kunlun.suse.cz> (raw)
In-Reply-To: <ed82620e-ecb1-4b7f-a84b-a0f3a773dd36@linux.ibm.com>
On Fri, Sep 18, 2026 at 02:56:40PM +0530, Shrikanth Hegde wrote:
> Hi Michal.
>
> On 9/17/26 7:45 PM, Shrikanth Hegde wrote:
> >
> > Hi Michal,
> >
> > > >
> > > > Give it a try.
> > > >
> > > > I am suspecting both lockup, stack corruptions are secondary symptoms here.
> > > > While recreate, I have different type of traces.
> > >
> > > Yes, it does work for the crash I see.
> >
> > Thanks. Give me sometime to see further on that. Didn't get any time today.
> >
> This is going to be the fix IMO. It passes all the recreates i have as of now.
> (Please ignore the whitespace mangling if any)
>
> Let me write changelog and send it across.
> ---
>
> diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S
> index 6599fe3c6234..54c8727b48cd 100644
> --- a/arch/powerpc/kernel/trace/ftrace_entry.S
> +++ b/arch/powerpc/kernel/trace/ftrace_entry.S
> @@ -220,7 +220,9 @@
> /* Restore gprs */
> .if \allregs == 1
> - REST_GPRS(2, 31, r1)
> + REST_GPRS(2, 12, r1)
> + /* Do not restore a stale PACA pointer if the task migrated */
> + REST_GPRS(14, 31, r1)
> .else
> REST_GPRS(3, 10, r1)
> #if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
This also works
Thanks
Michal
next prev parent reply other threads:[~2026-09-18 11:52 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-14 14:02 [Linux PPC] KVM PR and KVM HV do not work if the kernel was compiled with PREEMPT Christian Zigotzky
2026-02-17 5:02 ` Shrikanth Hegde
2026-02-17 8:52 ` Christian Zigotzky
2026-02-17 9:03 ` Shrikanth Hegde
2026-02-17 9:44 ` Christian Zigotzky
2026-02-17 10:17 ` Madhavan Srinivasan
2026-02-17 10:26 ` Christian Zigotzky
2026-02-17 11:34 ` Shrikanth Hegde
2026-02-21 5:30 ` Christian Zigotzky
2026-02-23 3:45 ` Shrikanth Hegde
2026-02-23 16:48 ` [Linux PPC] 7.0-rc1: e500_mmu.c:923:26: error: assignment to 'struct tlbe_priv *' from incompatible pointer type 'struct tlbe_ref *' Christian Zigotzky
2026-02-23 18:07 ` Christophe Leroy (CS GROUP)
2026-02-23 19:38 ` Christophe Leroy (CS GROUP)
2026-02-23 22:40 ` Kees Cook
2026-02-24 6:30 ` Christian Zigotzky
2026-02-24 7:18 ` Christophe Leroy (CS GROUP)
2026-02-25 5:54 ` [Linux PPC] Disable PREEMPT Christian Zigotzky
2026-02-25 6:23 ` Shrikanth Hegde
2026-02-25 7:16 ` Christophe Leroy (CS GROUP)
2026-02-25 11:36 ` Peter Zijlstra
2026-02-26 5:37 ` Christian Zigotzky
2026-02-26 13:24 ` Christophe Leroy (CS GROUP)
2026-09-03 9:53 ` Michal Suchánek
2026-09-03 10:56 ` Shrikanth Hegde
2026-09-03 11:25 ` Michal Suchánek
2026-09-03 11:31 ` Shrikanth Hegde
2026-09-03 11:40 ` Michal Suchánek
2026-09-03 12:04 ` Shrikanth Hegde
2026-09-03 12:25 ` Michal Suchánek
2026-09-03 12:36 ` Harsh Prateek Bora
2026-09-03 12:55 ` Michal Suchánek
2026-09-03 15:17 ` Amit Machhiwal
2026-09-03 13:28 ` Michal Suchánek
2026-09-04 7:39 ` Michal Suchánek
2026-09-21 8:06 ` Michal Suchánek
2026-09-21 16:46 ` Michal Suchánek
2026-09-21 17:20 ` Shrikanth Hegde
2026-09-22 8:22 ` Michal Suchánek
2026-09-03 17:22 ` Shrikanth Hegde
2026-09-04 7:35 ` Michal Suchánek
2026-09-04 9:04 ` Shrikanth Hegde
2026-09-10 8:59 ` Michal Suchánek
2026-09-10 10:41 ` Shrikanth Hegde
2026-09-10 11:29 ` Michal Suchánek
2026-09-10 12:16 ` Michal Suchánek
2026-09-11 17:09 ` Shrikanth Hegde
2026-09-14 10:58 ` Michal Suchánek
2026-09-15 5:47 ` Narayana Murty N
2026-09-15 7:35 ` Michal Suchánek
2026-09-15 9:08 ` Shrikanth Hegde
2026-09-16 18:11 ` Shrikanth Hegde
2026-09-17 10:14 ` Michal Suchánek
2026-09-17 10:28 ` Shrikanth Hegde
2026-09-17 13:12 ` Michal Suchánek
2026-09-17 14:15 ` Shrikanth Hegde
2026-09-18 2:39 ` Christian Zigotzky
2026-09-18 7:10 ` Michal Suchánek
2026-09-20 11:49 ` Christian Zigotzky
2026-09-20 13:04 ` Christian Zigotzky
2026-09-21 5:12 ` Shrikanth Hegde
2026-09-23 5:09 ` Christian Zigotzky
2026-09-23 5:13 ` Shrikanth Hegde
2026-09-23 16:01 ` Christian Zigotzky
2026-09-23 18:42 ` Shrikanth Hegde
2026-09-24 17:47 ` Christian Zigotzky
2026-09-25 6:40 ` Shrikanth Hegde
2026-09-18 9:26 ` Shrikanth Hegde
2026-09-18 11:52 ` Michal Suchánek [this message]
2026-09-04 8:55 ` Christian Zigotzky
2026-09-04 9:20 ` Christian Zigotzky
2026-09-04 9:24 ` Shrikanth Hegde
2026-09-04 9:34 ` Christian Zigotzky
2026-09-05 13:07 ` Christian Zigotzky
2026-09-07 8:50 ` Michal Suchánek
2026-09-07 11:32 ` Christian Zigotzky
2026-09-10 8:54 ` Michal Suchánek
2026-09-10 10:31 ` Michal Suchánek
2026-09-10 11:31 ` Michal Suchánek
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