From: Bharata B Rao <bharata@linux.ibm.com>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linux-next@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
LKML <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: PowerPC guest getting "BUG: scheduling while atomic" on linux-next-20210623 during secondary CPUs bringup
Date: Fri, 25 Jun 2021 11:20:09 +0530 [thread overview]
Message-ID: <YNVukVCgPjCksagq@in.ibm.com> (raw)
In-Reply-To: <20210625054608.fmwt7lxuhp7inkjx@linux.vnet.ibm.com>
On Fri, Jun 25, 2021 at 11:16:08AM +0530, Srikar Dronamraju wrote:
> * Bharata B Rao <bharata@linux.ibm.com> [2021-06-24 21:25:09]:
>
> > A PowerPC KVM guest gets the following BUG message when booting
> > linux-next-20210623:
> >
> > smp: Bringing up secondary CPUs ...
> > BUG: scheduling while atomic: swapper/1/0/0x00000000
> > no locks held by swapper/1/0.
> > Modules linked in:
> > CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.13.0-rc7-next-20210623
> > Call Trace:
> > [c00000000ae5bc20] [c000000000badc64] dump_stack_lvl+0x98/0xe0 (unreliable)
> > [c00000000ae5bc60] [c000000000210200] __schedule_bug+0xb0/0xe0
> > [c00000000ae5bcd0] [c000000001609e28] __schedule+0x1788/0x1c70
> > [c00000000ae5be20] [c00000000160a8cc] schedule_idle+0x3c/0x70
> > [c00000000ae5be50] [c00000000022984c] do_idle+0x2bc/0x420
> > [c00000000ae5bf00] [c000000000229d88] cpu_startup_entry+0x38/0x40
> > [c00000000ae5bf30] [c0000000000666c0] start_secondary+0x290/0x2a0
> > [c00000000ae5bf90] [c00000000000be54] start_secondary_prolog+0x10/0x14
> >
> > <The above repeats for all the secondary CPUs>
> >
> > smp: Brought up 2 nodes, 16 CPUs
> > numa: Node 0 CPUs: 0-7
> > numa: Node 1 CPUs: 8-15
> >
> > This seems to have started from next-20210521 and isn't seen on
> > next-20210511.
> >
>
> Bharata,
>
> I think the regression is due to Commit f1a0a376ca0c ("sched/core:
> Initialize the idle task with preemption disabled")
>
> Can you please try with the above commit reverted?
Yes, reverting that commit helps.
Regards,
Bharata.
WARNING: multiple messages have this Message-ID (diff)
From: Bharata B Rao <bharata@linux.ibm.com>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>,
linux-next@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Ingo Molnar <mingo@kernel.org>
Subject: Re: PowerPC guest getting "BUG: scheduling while atomic" on linux-next-20210623 during secondary CPUs bringup
Date: Fri, 25 Jun 2021 11:20:09 +0530 [thread overview]
Message-ID: <YNVukVCgPjCksagq@in.ibm.com> (raw)
In-Reply-To: <20210625054608.fmwt7lxuhp7inkjx@linux.vnet.ibm.com>
On Fri, Jun 25, 2021 at 11:16:08AM +0530, Srikar Dronamraju wrote:
> * Bharata B Rao <bharata@linux.ibm.com> [2021-06-24 21:25:09]:
>
> > A PowerPC KVM guest gets the following BUG message when booting
> > linux-next-20210623:
> >
> > smp: Bringing up secondary CPUs ...
> > BUG: scheduling while atomic: swapper/1/0/0x00000000
> > no locks held by swapper/1/0.
> > Modules linked in:
> > CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.13.0-rc7-next-20210623
> > Call Trace:
> > [c00000000ae5bc20] [c000000000badc64] dump_stack_lvl+0x98/0xe0 (unreliable)
> > [c00000000ae5bc60] [c000000000210200] __schedule_bug+0xb0/0xe0
> > [c00000000ae5bcd0] [c000000001609e28] __schedule+0x1788/0x1c70
> > [c00000000ae5be20] [c00000000160a8cc] schedule_idle+0x3c/0x70
> > [c00000000ae5be50] [c00000000022984c] do_idle+0x2bc/0x420
> > [c00000000ae5bf00] [c000000000229d88] cpu_startup_entry+0x38/0x40
> > [c00000000ae5bf30] [c0000000000666c0] start_secondary+0x290/0x2a0
> > [c00000000ae5bf90] [c00000000000be54] start_secondary_prolog+0x10/0x14
> >
> > <The above repeats for all the secondary CPUs>
> >
> > smp: Brought up 2 nodes, 16 CPUs
> > numa: Node 0 CPUs: 0-7
> > numa: Node 1 CPUs: 8-15
> >
> > This seems to have started from next-20210521 and isn't seen on
> > next-20210511.
> >
>
> Bharata,
>
> I think the regression is due to Commit f1a0a376ca0c ("sched/core:
> Initialize the idle task with preemption disabled")
>
> Can you please try with the above commit reverted?
Yes, reverting that commit helps.
Regards,
Bharata.
next prev parent reply other threads:[~2021-06-25 5:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-24 15:55 PowerPC guest getting "BUG: scheduling while atomic" on linux-next-20210623 during secondary CPUs bringup Bharata B Rao
2021-06-24 15:55 ` Bharata B Rao
2021-06-25 5:46 ` Srikar Dronamraju
2021-06-25 5:46 ` Srikar Dronamraju
2021-06-25 5:50 ` Bharata B Rao [this message]
2021-06-25 5:50 ` Bharata B Rao
2021-06-25 7:28 ` Peter Zijlstra
2021-06-25 7:28 ` Peter Zijlstra
2021-06-25 8:53 ` Bharata B Rao
2021-06-25 8:53 ` Bharata B Rao
2021-06-25 10:16 ` Peter Zijlstra
2021-06-25 10:16 ` Peter Zijlstra
2021-06-25 12:32 ` Bharata B Rao
2021-06-25 12:32 ` Bharata B Rao
2021-06-25 9:02 ` Valentin Schneider
2021-06-25 9:02 ` Valentin Schneider
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