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Date:   Fri, 19 Aug 2022 12:45:34 +0200
From:   Pavel Machek <pavel@denx.de>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Mikulas Patocka <mpatocka@redhat.com>,
        Song Liu <song@kernel.org>, Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH 5.15 089/779] md-raid10: fix KASAN warning
Message-ID: <20220819104534.GA11901@duo.ucw.cz>
References: <20220815180337.130757997@linuxfoundation.org>
 <20220815180341.087873206@linuxfoundation.org>
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Hi!

> From: Mikulas Patocka <mpatocka@redhat.com>
>=20
> commit d17f744e883b2f8d13cca252d71cfe8ace346f7d upstream.
>=20
> There's a KASAN warning in raid10_remove_disk when running the lvm
> test lvconvert-raid-reshape.sh. We fix this warning by verifying that the
> value "number" is valid.
>=20
> BUG: KASAN: slab-out-of-bounds in raid10_remove_disk+0x61/0x2a0 [raid10]
> Read of size 8 at addr ffff889108f3d300 by task mdX_raid10/124682

Is this place for array_index_nospec?

Best regards,
								Pavel

> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -2139,9 +2139,12 @@ static int raid10_remove_disk(struct mdd
>  	int err =3D 0;
>  	int number =3D rdev->raid_disk;
>  	struct md_rdev **rdevp;
> -	struct raid10_info *p =3D conf->mirrors + number;
> +	struct raid10_info *p;
> =20
>  	print_conf(conf);
> +	if (unlikely(number >=3D mddev->raid_disks))
> +		return 0;
> +	p =3D conf->mirrors + number;
>  	if (rdev =3D=3D p->rdev)
>  		rdevp =3D &p->rdev;
>  	else if (rdev =3D=3D p->replacement)
>=20

--=20
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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