linux-kernel - Re: [PATCH] x86/sgx: Fix deadloop in __sgx_alloc_epc

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Message-ID: <ZtB2L2yOHP-Um5pp@ziqianlu-kbl>
Date: Thu, 29 Aug 2024 21:22:55 +0800
From: Aaron Lu <aaron.lu@...el.com>
To: "Huang, Kai" <kai.huang@...el.com>
CC: "jarkko@...nel.org" <jarkko@...nel.org>, "dave.hansen@...ux.intel.com"
	<dave.hansen@...ux.intel.com>, "linux-sgx@...r.kernel.org"
	<linux-sgx@...r.kernel.org>, "Luo, Zhimin" <zhimin.luo@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH] x86/sgx: Fix deadloop in __sgx_alloc_epc_page()

On Thu, Aug 29, 2024 at 03:56:39PM +0800, Huang, Kai wrote:
> Actually run spell check this time ...
> 
> On Thu, 2024-08-29 at 10:38 +0800, Aaron Lu wrote:
> > When current node doesn't have a EPC section configured by firmware and
> 
> "current node" -> "the current node"
> 
> "a EPC section" -> "an EPC section"
> 
> > all other EPC sections memory are used up, CPU can stuck inside the
> 
> "EPC sections memory" -> "EPC sections"
> 
> "can stuck" -> "can get stuck"
> 
> > while loop in __sgx_alloc_epc_page() forever and soft lockup will happen.
> > Note how nid_of_current will never equal to nid in that while loop because
> > nid_of_current is not set in sgx_numa_mask.
> > 
> > Also worth mentioning is that it's perfectly fine for firmware to not
> > seup an EPC section on a node. Setting an EPC section on each node can
> > be good for performance but that's not a requirement functionality wise.
> > 
> 
> [...]

Thank you Kai for your detailed review, will reword the changelog
according to your suggestions when sending the next version.