linux-kernel - Re: [PATCH v5 3/6] arch/x86: Implement text_alloc() and text

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Date:   Fri, 24 Jul 2020 11:22:58 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Marco Elver <elver@...gle.com>,
        Babu Moger <Babu.Moger@....com>,
        Brian Gerst <brgerst@...il.com>,
        Nayna Jain <nayna@...ux.ibm.com>
Subject: Re: [PATCH v5 3/6] arch/x86: Implement text_alloc() and text_free()


* Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com> wrote:

> +void text_free(void *region)
> +{
> +	/*
> +	 * This memory may be RO, and freeing RO memory in an interrupt is not
> +	 * supported by vmalloc.
> +	 */
> +	lockdep_assert_irqs_enabled();
> +
> +	vfree(region);

Had to dig around a bit to find the source of this restriction. Might 
make sense to clarify this comment to:

	/*
	 * This memory may be read-only, and freeing VM_FLUSH_RESET_PERMS memory
	 * in an interrupt is not supported by vmalloc.
	 */

Thanks,

	Ingo