From: Xiong Zhou <jencce.kernel@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Andreas Herrmann <aherrmann@suse.com>,
Jens Axboe <axboe@kernel.dk>
Subject: Re: 4.5.0+ panic when setup loop device
Date: Fri, 18 Mar 2016 10:31:19 +0800 [thread overview]
Message-ID: <CADJHv_s+5jbuD70Nd9eDbjOAwrP5vuugudqjVxvHorji=XEOVQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1603171223480.3978@nanos>
Hi,
On Thu, Mar 17, 2016 at 7:39 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> B1;2802;0cOn Thu, 17 Mar 2016, Peter Zijlstra wrote:
>
>> On Thu, Mar 17, 2016 at 11:21:24AM +0100, Thomas Gleixner wrote:
>> > On Thu, 17 Mar 2016, Peter Zijlstra wrote:
>> >
>> > > Could you please try? I'm not sure how this would explain your loop
>> > > device bug fail, but it certainly pointed towards broken.
>> >
>> > It definitely does not explain it. The wreckage that topo stuff causes is that
>> > it disables a cpu, but that really is not a reason for block/loop to explode.
>>
>> Right. Sadly I could not reproduce that error on my machine. But we can
>> at least start by fixing the 'obvious' problems and then maybe we get
>> more clues ;-)
>
> I'm able to reproduce by rejecting a cpu in that topology map function
> forcefully.
>
> That stuff explodes, because the block-mq code assumes that cpu_possible_mask
> has no holes.
>
> #define queue_for_each_ctx(q, ctx, i) \
> for ((i) = 0; (i) < (q)->nr_queues && \
> ({ ctx = per_cpu_ptr((q)->queue_ctx, (i)); 1; }); (i)++)
>
> is what makes that assumption about a consecutive possible mask.
>
> The cure for now is the patch below on top of PeterZ's patch.
No panic with both Peter's patch and yours.
Thanks all.
--
Xiong
>
> But we have to clarify and document whether holes in cpu_possible_mask are not
> allowed at all or if code like the above is simply broken.
>
> Thanks,
>
> tglx
> ---
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 643dbdccf4bc..f2ed8a01f870 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -345,7 +345,6 @@ static void __init smp_init_package_map(void)
> continue;
> pr_warn("CPU %u APICId %x disabled\n", cpu, apicid);
> per_cpu(x86_bios_cpu_apicid, cpu) = BAD_APICID;
> - set_cpu_possible(cpu, false);
> set_cpu_present(cpu, false);
> }
> }
>
>
>
>
>
>
>
>
next prev parent reply other threads:[~2016-03-18 2:31 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-16 6:48 4.5.0+ panic when setup loop device Xiong Zhou
2016-03-16 15:26 ` Thomas Gleixner
2016-03-17 1:56 ` Xiong Zhou
2016-03-17 9:52 ` Peter Zijlstra
2016-03-17 9:56 ` Peter Zijlstra
2016-03-17 10:21 ` Thomas Gleixner
2016-03-17 10:26 ` Peter Zijlstra
2016-03-17 11:39 ` Thomas Gleixner
2016-03-17 11:51 ` Peter Zijlstra
2016-03-17 11:57 ` Borislav Petkov
2016-03-17 12:01 ` Thomas Gleixner
2016-03-17 16:42 ` Jens Axboe
2016-03-17 18:26 ` Jens Axboe
2016-03-17 20:20 ` Thomas Gleixner
2016-03-17 20:23 ` Jens Axboe
2016-03-17 20:30 ` Thomas Gleixner
2016-03-17 20:41 ` Jens Axboe
2016-03-18 2:31 ` Xiong Zhou [this message]
2016-03-18 4:11 ` Mike Galbraith
2016-03-18 7:51 ` Peter Zijlstra
2016-03-18 10:15 ` Peter Zijlstra
2016-03-18 12:39 ` Mike Galbraith
2016-03-18 13:32 ` Peter Zijlstra
2016-03-18 14:07 ` Mike Galbraith
2016-03-18 11:55 ` Thomas Gleixner
2016-03-18 12:39 ` Mike Galbraith
2016-03-19 9:31 ` [tip:x86/urgent] x86/topology: Use total_cpus not nr_cpu_ids for logical packages tip-bot for Thomas Gleixner
2016-03-29 8:48 ` [tip:x86/urgent] x86/topology: Fix AMD core count tip-bot for Peter Zijlstra
2016-03-18 15:03 [PATCH 0/3] x86 topology fixes Peter Zijlstra
2016-03-18 15:03 ` [PATCH 1/3] x86/topology: Fix logical pkg mapping Peter Zijlstra
2016-03-19 9:30 ` [tip:x86/urgent] x86/topology: Fix logical package mapping tip-bot for Peter Zijlstra
2016-03-18 15:03 ` [PATCH 2/3] x86/topology: Fix AMD core count Peter Zijlstra
2016-03-18 16:41 ` Borislav Petkov
2016-03-21 3:07 ` Huang Rui
2016-03-21 3:46 ` Huang Rui
2016-03-21 8:26 ` Borislav Petkov
2016-03-21 9:18 ` Huang Rui
2016-03-21 8:56 ` Thomas Gleixner
2016-03-21 8:21 ` Peter Zijlstra
2016-03-21 9:46 ` Huang Rui
2016-03-21 13:57 ` Borislav Petkov
2016-03-22 8:10 ` Sherry Hurwitz
2016-03-22 11:22 ` Borislav Petkov
2016-03-21 8:23 ` Borislav Petkov
2016-03-21 10:05 ` Huang Rui
2016-03-21 10:23 ` Borislav Petkov
2016-03-19 9:24 ` Thomas Gleixner
2016-03-19 15:56 ` Borislav Petkov
2016-03-20 10:39 ` Peter Zijlstra
2016-03-20 11:04 ` Borislav Petkov
2016-03-20 12:32 ` Peter Zijlstra
2016-03-20 12:46 ` Peter Zijlstra
2016-03-20 13:09 ` Borislav Petkov
2016-03-20 17:08 ` Peter Zijlstra
2016-03-20 18:46 ` Borislav Petkov
2016-03-29 8:49 ` [tip:x86/urgent] perf/x86/amd: Cleanup Fam10h NB event constraints tip-bot for Peter Zijlstra
2016-03-22 7:56 ` [PATCH 2/3] x86/topology: Fix AMD core count Huang Rui
2016-03-18 15:03 ` [PATCH 3/3] x86/topology: Fix Intel HT disable Peter Zijlstra
2016-03-19 9:31 ` [tip:x86/urgent] " tip-bot for Peter Zijlstra
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