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Date: Mon, 12 Feb 2024 14:43:28 -0500
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Cc: yazen.ghannam@amd.com, "Mehta, Sohil" <sohil.mehta@intel.com>,
 "x86@kernel.org" <x86@kernel.org>,
 "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 Avadhut Naik <avadhut.naik@amd.com>
Subject: Re: [PATCH 2/2] x86/MCE: Add command line option to extend MCE
 Records pool
Content-Language: en-US
To: "Luck, Tony" <tony.luck@intel.com>, Borislav Petkov <bp@alien8.de>,
 "Naik, Avadhut" <avadnaik@amd.com>
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From: Yazen Ghannam <yazen.ghannam@amd.com>
In-Reply-To: <SJ1PR11MB6083CF3400AD2F2047D65E17FC482@SJ1PR11MB6083.namprd11.prod.outlook.com>
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On 2/12/2024 1:58 PM, Luck, Tony wrote:
>> I need to look more at the genpool code, but I thought I'd ask too.
> 
> Yazen,
> 
> gen_pool_add_owner() is the code that adds an extra chunk to an existing genpool.
> 
> This bit doesn't look obviously safe against a #MC at the wrong moment in the middle of
> the list_add_rcu()
> 
>          spin_lock(&pool->lock);
>          list_add_rcu(&chunk->next_chunk, &pool->chunks);
>          spin_unlock(&pool->lock);
> 

Thanks Tony.

So the concern is not about traversal, but rather that the #MC can break the
list_add_rcu(). Is this correct?


Thanks,
Yazen