linux-kernel - Re: [PATCH v6 7/9] kselftest/arm64/mte: add verification for address tag in signal handler

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Message-ID: <5d2a3abd-f19d-4fe0-adfa-9a9860d7404d@sirena.org.uk>
Date: Wed, 11 Jun 2025 13:12:24 +0100
From: Mark Brown <broonie@...nel.org>
To: Yeoreum Yun <yeoreum.yun@....com>
Cc: catalin.marinas@....com, pcc@...gle.com, will@...nel.org,
	anshuman.khandual@....com, joey.gouly@....com,
	yury.khrustalev@....com, maz@...nel.org, oliver.upton@...ux.dev,
	frederic@...nel.org, akpm@...ux-foundation.org, surenb@...gle.com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org
Subject: Re: [PATCH v6 7/9] kselftest/arm64/mte: add verification for address
 tag in signal handler

On Wed, Jun 11, 2025 at 10:41:05AM +0100, Yeoreum Yun wrote:
> Add the address tag [63:60] verification when synchronous mte fault is happen.
> when signal handler is registered with SA_EXPOSE_TAGBITS,
> address includes not only memory tag [59:56] but also address tag.
> Therefore, when verify fault address location, remove both tags

Reviewed-by: Mark Brown <broonie@...nel.org>

though if you're doing a new version there's minor stylistic stuff:

>  		/* Compare the context for precise error */
>  		else if (si->si_code == SEGV_MTESERR) {
> +		 	if ((!mtefar_support && si_atag) || (si_atag != MT_FETCH_ATAG(cur_mte_cxt.trig_addr))) {
> +			  ksft_print_msg("Invalid MTE synchronous exception caught for address tag! si_tag=%x, si_atag: %x\n", si_tag, si_atag);
> +			  exit(KSFT_FAIL);
> +			}

Indentation seems off, also there's ksft_exit_fail_msg() but either way
works.

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