linux-kernel - Re: [PATCH v2 8/8] vdso: Modify getrandom to include the correct namespace.

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Message-ID: <ZvH1rVYy0iNCTpds@zx2c4.com>
Date: Tue, 24 Sep 2024 01:11:41 +0200
From: "Jason A. Donenfeld" <Jason@...c4.com>
To: Vincenzo Frascino <vincenzo.frascino@....com>
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-mm@...ck.org, Andy Lutomirski <luto@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Naveen N Rao <naveen@...nel.org>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H . Peter Anvin" <hpa@...or.com>, Theodore Ts'o <tytso@....edu>,
	Arnd Bergmann <arnd@...db.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: Re: [PATCH v2 8/8] vdso: Modify getrandom to include the correct
 namespace.

On Mon, Sep 23, 2024 at 03:19:43PM +0100, Vincenzo Frascino wrote:
> -		params->mmap_prot = PROT_READ | PROT_WRITE;
> -		params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
> +		params->mmap_prot = VDSO_MMAP_PROT;
> +		params->mmap_flags = VDSO_MMAP_FLAGS;

The code that's being deleted is meaningful and descriptive. The code
that's being added is confusing. What on earth is a vdso mmap flag? Not
only is it indirection, which makes it harder to understand, but its
indirection through a meaninglessly generic name that suggests to the
user there's some additional property of the vdso or mmap or both that
would imply a specific flag for these general things. In reality, the
thing in question is about what getrandom.c uses.