linux-kernel - Re: [PATCH v8 1/5] x86/sgx: Introduce a counter to count the sgx_(vepc

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Message-ID: <4838ad3b-af1c-481b-acb9-9c33943a018b@intel.com>
Date: Mon, 21 Jul 2025 09:47:49 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: Elena Reshetova <elena.reshetova@...el.com>
Cc: jarkko@...nel.org, seanjc@...gle.com, kai.huang@...el.com,
 mingo@...nel.org, linux-sgx@...r.kernel.org, linux-kernel@...r.kernel.org,
 x86@...nel.org, asit.k.mallick@...el.com, vincent.r.scarlata@...el.com,
 chongc@...gle.com, erdemaktas@...gle.com, vannapurve@...gle.com,
 bondarn@...gle.com, scott.raynor@...el.com
Subject: Re: [PATCH v8 1/5] x86/sgx: Introduce a counter to count the
 sgx_(vepc_)open()

On 7/15/25 05:40, Elena Reshetova wrote:
> +int sgx_inc_usage_count(void)
> +{
> +	sgx_usage_count++;
> +	return 0;
> +}
> +
> +void sgx_dec_usage_count(void)
> +{
> +	sgx_usage_count--;
> +}

Gah.

I know this gets fixed up later in the series with the mutex, but this
code is broken and racy until that point.

I'd rather this do _nothing_:

	int sgx_inc_usage_count(void)
	{
		return 0;
	}

than a foo++ which just plain doesn't work.