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Date:   Fri, 13 Nov 2020 18:55:08 +0100
From:   Marco Elver <elver@google.com>
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 11/20] kasan: add and integrate kasan boot parameters
Message-ID: <20201113175508.GB3175464@elver.google.com>
References: <cover.1605046662.git.andreyknvl@google.com>
 <fdf9e3aec8f57ebb2795710195f8aaf79e3b45bd.1605046662.git.andreyknvl@google.com>
 <20201113175254.GA3175464@elver.google.com>
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User-Agent: Mutt/1.14.6 (2020-07-11)
Precedence: bulk

On Fri, Nov 13, 2020 at 06:52PM +0100, Marco Elver wrote:
> On Tue, Nov 10, 2020 at 11:20PM +0100, 'Andrey Konovalov' via kasan-dev wrote:
> [...]
> > +/* kasan.mode=off/prod/full */
> > +static int __init early_kasan_mode(char *arg)
> > +{
> > +	if (!arg)
> > +		return -EINVAL;
> > +
> > +	if (!strcmp(arg, "off"))
> > +		kasan_arg_mode = KASAN_ARG_MODE_OFF;
> > +	else if (!strcmp(arg, "prod"))
> > +		kasan_arg_mode = KASAN_ARG_MODE_PROD;
> > +	else if (!strcmp(arg, "full"))
> > +		kasan_arg_mode = KASAN_ARG_MODE_FULL;
> > +	else
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> > +early_param("kasan.mode", early_kasan_mode);
> > +
> > +/* kasan.stack=off/on */
> > +static int __init early_kasan_flag_stacktrace(char *arg)
> > +{
> > +	if (!arg)
> > +		return -EINVAL;
> > +
> > +	if (!strcmp(arg, "off"))
> > +		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF;
> > +	else if (!strcmp(arg, "on"))
> > +		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON;
> > +	else
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> > +early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
> > +
> > +/* kasan.fault=report/panic */
> > +static int __init early_kasan_fault(char *arg)
> > +{
> > +	if (!arg)
> > +		return -EINVAL;
> > +
> > +	if (!strcmp(arg, "report"))
> > +		kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
> > +	else if (!strcmp(arg, "panic"))
> > +		kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
> > +	else
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> [...]
> 
> The above could be simplified, see suggestion below.
> 
> Thanks,
> -- Marco
> 
> ------ >8 ------
> 
> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> index c91f2c06ecb5..71fc481ad21d 100644
> --- a/mm/kasan/hw_tags.c
> +++ b/mm/kasan/hw_tags.c
> @@ -64,10 +64,8 @@ static int __init early_kasan_mode(char *arg)
>  		kasan_arg_mode = KASAN_ARG_MODE_PROD;
>  	else if (!strcmp(arg, "full"))
>  		kasan_arg_mode = KASAN_ARG_MODE_FULL;
> -	else
> -		return -EINVAL;
>  
> -	return 0;
> +	return -EINVAL;

Ah that clearly doesn't work. Hmm, never mind this suggestion, sorry.

Thanks,
-- Marco