Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 23 Aug 2022 12:26:40 +0100
From:   Mark Brown <broonie@kernel.org>
To:     Wang ShaoBo <bobo.shaobowang@huawei.com>
Cc:     catalin.marinas@arm.com, weiyongjun1@huawei.com,
        guohanjun@huawei.com, oleg@redhat.com, will@kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64/sme: Clearing TIF_SVE but not TIF_SME in za_set()
Message-ID: <YwS5cN7GlbdR5IQU@sirena.org.uk>
References: <20220823015627.4161141-1-bobo.shaobowang@huawei.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
        protocol="application/pgp-signature"; boundary="Grr7xBdWJnPqcDeU"
Content-Disposition: inline
In-Reply-To: <20220823015627.4161141-1-bobo.shaobowang@huawei.com>
Precedence: bulk


--Grr7xBdWJnPqcDeU
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Tue, Aug 23, 2022 at 09:56:27AM +0800, Wang ShaoBo wrote:

> Clearing target's TIF_SVE but not current's TIF_SME in za_set(), as it indicates
> target's SVE storage unavailable.

> +++ b/arch/arm64/kernel/ptrace.c
> @@ -1084,7 +1084,7 @@ static int za_set(struct task_struct *target,
>  	if (!target->thread.sve_state) {
>  		sve_alloc(target);
>  		if (!target->thread.sve_state) {
> -			clear_thread_flag(TIF_SME);
> +			clear_tsk_thread_flag(target, TIF_SVE);
>  			ret = -ENOMEM;
>  			goto out;
>  		}

We didn't set TIF_SVE so we have no reason to clear it here, we know it
can't have been set since there was no sve_state allocated.  The clear
of TIF_SME is happening on the wrong task though, and TBH is just
redudnant for similar reasons.

--Grr7xBdWJnPqcDeU
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----

iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmMEuW8ACgkQJNaLcl1U
h9A/nwf+PMHHOdTHrCmXoakUYx/xyO07zoxAKWSbovxyoCSP1CReutGiC9tQM1VM
zbcDMjxZoxhbyLBuEeJaIPNt0v9ZzN89iSU7RGxS7D+rEv5KoGUGAyYckbKpSYfW
ul6Zz4rWh1LBCJwtrq60jUtApmTj+pu8xNKNK8Itd9KC5xia/TRCiVd4DAGvV1j1
pojDGfI1dgPhHUhZlpslMD+Hs3v6w0uQ7jhXcqERSwMuRpxz9FSQ1YIYKYNJg4Mj
omda9PxYr5rVMNNbw+DQ1E/LjtKzL+sgl4HWBdiLk8B9maABxnAwFrokHPxLxabS
abDtlQ7ReZIHMsIuLbexgD01HAsRIw==
=Y+xl
-----END PGP SIGNATURE-----

--Grr7xBdWJnPqcDeU--