From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B87EC433F5 for ; Mon, 6 Sep 2021 11:22:17 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0200960F43 for ; Mon, 6 Sep 2021 11:22:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0200960F43 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.179658.326047 (Exim 4.92) (envelope-from ) id 1mNChV-0004mD-0J; Mon, 06 Sep 2021 11:22:09 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 179658.326047; Mon, 06 Sep 2021 11:22:08 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mNChU-0004m6-TA; Mon, 06 Sep 2021 11:22:08 +0000 Received: by outflank-mailman (input) for mailman id 179658; Mon, 06 Sep 2021 11:22:07 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mNChT-0004lB-2U for xen-devel@lists.xenproject.org; Mon, 06 Sep 2021 11:22:07 +0000 Received: from smtp-out2.suse.de (unknown [195.135.220.29]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 6da9db43-d88a-499b-b0fd-cecfad644a93; Mon, 06 Sep 2021 11:22:05 +0000 (UTC) Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 0F59A1FEDA; Mon, 6 Sep 2021 11:22:05 +0000 (UTC) Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id D706F1395F; Mon, 6 Sep 2021 11:22:04 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id vfZkMtz5NWHMHgAAGKfGzw (envelope-from ); Mon, 06 Sep 2021 11:22:04 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 6da9db43-d88a-499b-b0fd-cecfad644a93 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1630927325; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=bZxp9VPY5c6s8wGWdcldGfjpDN2Ri4rZPWfB5DP4AhM=; b=bEaIQLE5MuOXofj7XevBMD0xy+9D6CkEGI6CYk3d3+8iq+g/iihWrHggeKk2q1oegYM5nh CURX71E2d7T1M4vuz5eax8R5OIoub50wNLYiv1z+l+wn5AYA2uuxlnskgfja76+bxCNWMb f0qRM0QDeXn+VI593KSgj6yLSr62CBY= Subject: Re: [PATCH] xen/sched: fix sched_move_domain() for domain without vcpus To: Andrew Cooper , xen-devel@lists.xenproject.org Cc: George Dunlap , Dario Faggioli , Bertrand Marquis References: <20210906110057.15384-1-jgross@suse.com> <0006eb7d-a9d5-16a3-1418-a1d28c4c9a92@citrix.com> From: Juergen Gross Message-ID: <72a7728d-1b30-5cc7-981d-50471e77126b@suse.com> Date: Mon, 6 Sep 2021 13:22:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <0006eb7d-a9d5-16a3-1418-a1d28c4c9a92@citrix.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="DqXVcNp9qsxotgnM55gXR6Fc3Gf5QKbfg" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --DqXVcNp9qsxotgnM55gXR6Fc3Gf5QKbfg Content-Type: multipart/mixed; boundary="VzyTPZaAbTyoAKrBL7tBm5kVgPMOxo8kl"; protected-headers="v1" From: Juergen Gross To: Andrew Cooper , xen-devel@lists.xenproject.org Cc: George Dunlap , Dario Faggioli , Bertrand Marquis Message-ID: <72a7728d-1b30-5cc7-981d-50471e77126b@suse.com> Subject: Re: [PATCH] xen/sched: fix sched_move_domain() for domain without vcpus References: <20210906110057.15384-1-jgross@suse.com> <0006eb7d-a9d5-16a3-1418-a1d28c4c9a92@citrix.com> In-Reply-To: <0006eb7d-a9d5-16a3-1418-a1d28c4c9a92@citrix.com> --VzyTPZaAbTyoAKrBL7tBm5kVgPMOxo8kl Content-Type: multipart/mixed; boundary="------------DF3084C52409BDBB90E4E232" Content-Language: en-US This is a multi-part message in MIME format. --------------DF3084C52409BDBB90E4E232 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 06.09.21 13:14, Andrew Cooper wrote: > On 06/09/2021 12:00, Juergen Gross wrote: >> In case a domain is created with a cpupool other than Pool-0 specified= >> it will be moved to that cpupool before any vcpus are allocated. >> >> This will lead to a NULL pointer dereference in sched_move_domain(). >> >> Fix that by tolerating vcpus not being allocated yet. >> >> Fixes: 70fadc41635b9b6 ("xen/cpupool: support moving domain between cp= upools with different granularity") >> Reported-by: Bertrand Marquis >> Reviewed-by: Bertrand Marquis >> Signed-off-by: Juergen Gross >> --- >> xen/common/sched/core.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c >> index 8d178baf3d..79c9100680 100644 >> --- a/xen/common/sched/core.c >> +++ b/xen/common/sched/core.c >> @@ -671,6 +671,10 @@ int sched_move_domain(struct domain *d, struct cp= upool *c) >> =20 >> for ( unit_idx =3D 0; unit_idx < n_units; unit_idx++ ) >> { >> + /* Special case for move at domain creation time. */ >> + if ( !d->vcpu[unit_idx * gran] ) >> + break; >> + >> unit =3D sched_alloc_unit_mem(); >> if ( unit ) >> { >=20 > I think the logic would be clearer if you wrap the entire for loop in i= f > ( d->max_vcpus ). No, d->max_vcpus is not 0 here, otherwise n_units would be 0. > This loop is only allocating units in the new > scheduler for existing vcpus, so there's no point entering the loop at > all during domain creation. >=20 > Also, this removes a non-speculatively-guarded d->vcpu[] deference. I don't think this dereference is a real problem. In case you are worried about it we should replace the one further below, too. Juergen --------------DF3084C52409BDBB90E4E232 Content-Type: application/pgp-keys; name="OpenPGP_0xB0DE9DD628BF132F.asc" Content-Transfer-Encoding: quoted-printable Content-Description: OpenPGP public key Content-Disposition: attachment; filename="OpenPGP_0xB0DE9DD628BF132F.asc" -----BEGIN PGP PUBLIC KEY BLOCK----- xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOBy= cWx w3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJvedYm8O= f8Z d621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJNwQpd369y= 9bf IhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvxXP3FAp2pkW0xq= G7/ 377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEBAAHNHEp1ZXJnZW4gR= 3Jv c3MgPGpnQHBmdXBmLm5ldD7CwHkEEwECACMFAlOMcBYCGwMHCwkIBwMCAQYVCAIJCgsEFgIDA= QIe AQIXgAAKCRCw3p3WKL8TL0KdB/93FcIZ3GCNwFU0u3EjNbNjmXBKDY4FUGNQH2lvWAUy+dnyT= hpw dtF/jQ6j9RwE8VP0+NXcYpGJDWlNb9/JmYqLiX2Q3TyevpB0CA3dbBQp0OW0fgCetToGIQrg0= MbD 1C/sEOv8Mr4NAfbauXjZlvTj30H2jO0u+6WGM6nHwbh2l5O8ZiHkH32iaSTfN7Eu5RnNVUJbv= oPH Z8SlM4KWm8rG+lIkGurqqu5gu8q8ZMKdsdGC4bBxdQKDKHEFExLJK/nRPFmAuGlId1E3fe10v= 5QL +qHI3EIPtyfE7i9Hz6rVwi7lWKgh7pe0ZvatAudZ+JNIlBKptb64FaiIOAWDCx1SzR9KdWVyZ= 2Vu IEdyb3NzIDxqZ3Jvc3NAc3VzZS5jb20+wsB5BBMBAgAjBQJTjHCvAhsDBwsJCAcDAgEGFQgCC= QoL BBYCAwECHgECF4AACgkQsN6d1ii/Ey/HmQf/RtI7kv5A2PS4RF7HoZhPVPogNVbC4YA6lW7Dr= Wf0 teC0RR3MzXfy6pJ+7KLgkqMlrAbN/8Dvjoz78X+5vhH/rDLa9BuZQlhFmvcGtCF8eR0T1v0nC= /nu AFVGy+67q2DH8As3KPu0344TBDpAvr2uYM4tSqxK4DURx5INz4ZZ0WNFHcqsfvlGJALDeE0Lh= ITT d9jLzdDad1pQSToCnLl6SBJZjDOX9QQcyUigZFtCXFst4dlsvddrxyqT1f17+2cFSdu7+ynLm= XBK 7abQ3rwJY8SbRO2iRulogc5vr/RLMMlscDAiDkaFQWLoqHHOdfO9rURssHNN8WkMnQfvUewRz= 80h SnVlcmdlbiBHcm9zcyA8amdyb3NzQG5vdmVsbC5jb20+wsB5BBMBAgAjBQJTjHDXAhsDBwsJC= AcD AgEGFQgCCQoLBBYCAwECHgECF4AACgkQsN6d1ii/Ey8PUQf/ehmgCI9jB9hlgexLvgOtf7PJn= FOX gMLdBQgBlVPO3/D9R8LtF9DBAFPNhlrsfIG/SqICoRCqUcJ96Pn3P7UUinFG/I0ECGF4EvTE1= jnD kfJZr6jrbjgyoZHiw/4BNwSTL9rWASyLgqlA8u1mf+c2yUwcGhgkRAd1gOwungxcwzwqgljf0= N51 N5JfVRHRtyfwq/ge+YEkDGcTU6Y0sPOuj4Dyfm8fJzdfHNQsWq3PnczLVELStJNdapwPOoE+l= otu fe3AM2vAEYJ9rTz3Cki4JFUsgLkHFqGZarrPGi1eyQcXeluldO3m91NK/1xMI3/+8jbO0tsn1= tqS EUGIJi7ox80eSnVlcmdlbiBHcm9zcyA8amdyb3NzQHN1c2UuZGU+wsB5BBMBAgAjBQJTjHDrA= hsD BwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AACgkQsN6d1ii/Ey+LhQf9GL45eU5vOowA2u5N3= g3O ZUEBmDHVVbqMtzwlmNC4k9Kx39r5s2vcFl4tXqW7g9/ViXYuiDXb0RfUpZiIUW89siKrkzmQ5= dM7 wRqzgJpJwK8Bn2MIxAKArekWpiCKvBOB/Cc+3EXE78XdlxLyOi/NrmSGRIov0karw2RzMNOu5= D+j LRZQd1Sv27AR+IP3I8U4aqnhLpwhK7MEy9oCILlgZ1QZe49kpcumcZKORmzBTNh30FVKK1Evm= V2x AKDoaEOgQB4iFQLhJCdP1I5aSgM5IVFdn7v5YgEYuJYx37IoN1EblHI//x/e2AaIHpzK5h88N= Eaw QsaNRpNSrcfbFmAg987ATQRTjHAWAQgAyzH6AOODMBjgfWE9VeCgsrwH3exNAU32gLq2xvjpW= nHI s98ndPUDpnoxWQugJ6MpMncr0xSwFmHEgnSEjK/PAjppgmyc57BwKII3sV4on+gDVFJR6Y8ZR= wgn BC5mVM6JjQ5xDk8WRXljExRfUX9pNhdE5eBOZJrDRoLUmmjDtKzWaDhIg/+1Hzz93X4fCQkNV= bVF LELU9bMaLPBG/x5q4iYZ2k2ex6d47YE1ZFdMm6YBYMOljGkZKwYde5ldM9mo45mmwe0icXKLk= pEd IXKTZeKDO+Hdv1aqFuAcccTg9RXDQjmwhC3yEmrmcfl0+rPghO0Iv3OOImwTEe4co3c1mwARA= QAB wsBfBBgBAgAJBQJTjHAWAhsMAAoJELDendYovxMvQ/gH/1ha96vm4P/L+bQpJwrZ/dneZcmEw= Tbe 8YFsw2V/Buv6Z4Mysln3nQK5ZadD534CF7TDVft7fC4tU4PONxF5D+/tvgkPfDAfF77zy2AH1= vJz Q1fOU8lYFpZXTXIHb+559UqvIB8AdgR3SAJGHHt4RKA0F7f5ipYBBrC6cyXJyyoprT10EMvU8= VGi wXvTyJz3fjoYsdFzpWPlJEBRMedCot60g5dmbdrZ5DWClAr0yau47zpWj3enf1tLWaqcsuylW= svi uGjKGw7KHQd3bxALOknAp4dN3QwBYCKuZ7AddY9yjynVaD5X7nF9nO5BjR/i1DG86lem3iBDX= zXs ZDn8R38=3D =3D2wuH -----END PGP PUBLIC KEY BLOCK----- --------------DF3084C52409BDBB90E4E232-- --VzyTPZaAbTyoAKrBL7tBm5kVgPMOxo8kl-- --DqXVcNp9qsxotgnM55gXR6Fc3Gf5QKbfg Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsB5BAABCAAjFiEEhRJncuj2BJSl0Jf3sN6d1ii/Ey8FAmE1+dwFAwAAAAAACgkQsN6d1ii/Ey8T +gf/d689AFSV3hds3y/QXlpXUIPF3DagRR4HOLSSJeQ2q7/NgGTQ9fMDm0p2qMwCP4fIjNzHnsg9 Jb2W9kvV/y7PJ/LyhoXEwSyXc51zFqPgH7lJrCTP59lq2N7n6pxK8GxDOyX4maaIpQNmzDkwvCmz 3vIjbNbKzShLHV+0CZajwxoPEGaLOPcV10gI+VnfWU9Z+GtieDroDm028sqopjiz42yqCyE+eeHW YcDHIPGrlwknjlZnQowcXfadMDvYKBX9Cp397jDP8z0q6a0oxQOeukAG7/tJ3hTv2EE70CUwGt9j GUv6OK3UfK9ujo3fkbBN4kznB/dMJsLrx4g/rIkJWA== =vY95 -----END PGP SIGNATURE----- --DqXVcNp9qsxotgnM55gXR6Fc3Gf5QKbfg--