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Date: Wed, 31 Jan 2024 20:34:09 +0800
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Subject: Re: Re: [linus:master] [sched/eevdf] 2227a957e1:
 BUG:kernel_NULL_pointer_dereference,address
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To: Oliver Sang <oliver.sang@intel.com>
Cc: oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org,
 Peter Zijlstra <peterz@infradead.org>, aubrey.li@linux.intel.com,
 yu.c.chen@intel.com, Tiwei Bie <tiwei.btw@antgroup.com>
References: <202401301012.2ed95df0-oliver.sang@intel.com>
 <23cbb613-c8a2-4f07-b83b-fa3104bef642@bytedance.com>
 <ZbkDIlIR7qzPt7Vk@xsang-OptiPlex-9020>
From: Abel Wu <wuyun.abel@bytedance.com>
In-Reply-To: <ZbkDIlIR7qzPt7Vk@xsang-OptiPlex-9020>
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On 1/30/24 10:09 PM, Oliver Sang Wrote:
> hi, Abel,
> 
> On Tue, Jan 30, 2024 at 06:13:32PM +0800, Abel Wu wrote:
>> On 1/30/24 3:24 PM, kernel test robot Wrote:
>>>
>>> we found this issue happens in very random way (23 out of 999 runs).
>>> but keeps clean on parent.
>>
>> Thanks for reporting, I will try to reproduce the issue. Does the 'parent'
>> mean the same code branch without this commit?
> 
> 
> it just means the parent in git log.
> 
> xsang@inn:/c/repo/linux$ git log --oneline --graph 2227a957e1
> * 2227a957e1d5b sched/eevdf: Sort the rbtree by virtual deadline
> * 84db47ca7146d sched/numa: Fix mm numa_scan_seq based unconditional scan  <-- parent

Thanks for clarifying, Oliver. And can you please check the parent's
dmesg for the log:

	pr_err("EEVDF scheduling fail, picking leftmost\n");

which potentially turns a kernel panic to a message.