From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse Subject: Re: [PATCH RFC] solos-pci: Fix BUG() with shared skb Date: Tue, 15 Sep 2015 20:10:43 +0100 Message-ID: <1442344243.131189.26.camel@infradead.org> References: <1378223125.4210.11.camel@i7.infradead.org> <20130904.143056.1558570610941220565.davem@davemloft.net> <1378327275.2627.28.camel@shinybook.infradead.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="sha-1"; protocol="application/x-pkcs7-signature"; boundary="=-3KX7VBrR3KGKQBEzboQe" Cc: netdev@vger.kernel.org, linux-atm-general@lists.sourceforge.net To: simon@fire.lp0.eu Return-path: Received: from casper.infradead.org ([85.118.1.10]:46773 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751622AbbIOTKq (ORCPT ); Tue, 15 Sep 2015 15:10:46 -0400 In-Reply-To: <1378327275.2627.28.camel@shinybook.infradead.org> Sender: netdev-owner@vger.kernel.org List-ID: --=-3KX7VBrR3KGKQBEzboQe Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2013-09-04 at 21:41 +0100, David Woodhouse wrote: > On Wed, 2013-09-04 at 14:30 -0400, David Miller wrote: > > skb_realloc_headroom() should do everything you need. >=20 > Great, thanks! Something like this then... ?=20 > > diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c > index 32784d1..4492c0f 100644 > --- a/drivers/atm/solos-pci.c > +++ b/drivers/atm/solos-pci.c > @@ -1145,19 +1145,19 @@ static int psend(struct atm_vcc *vcc, struct sk_b= uff *skb) > > > > return 0; > > > } > =20 > -> > if (!skb_clone_writable(skb, sizeof(*header))) { > -> > > int expand_by =3D 0; > -> > > int ret; > - > -> > > if (skb_headroom(skb) < sizeof(*header)) > -> > > > expand_by =3D sizeof(*header) - skb_headroom(skb); > - > -> > > ret =3D pskb_expand_head(skb, expand_by, 0, GFP_ATOMIC); > -> > > if (ret) { > -> > > > dev_warn(&card->dev->dev, "pskb_expand_head failed.\n"); > -> > > > solos_pop(vcc, skb); > -> > > > return ret; > -> > > } > +> > if (skb_headroom(skb) < sizeof(*header)) { > +> > > struct sk_buff *nskb; > + > +> > > nskb =3D skb_realloc_headroom(skb, sizeof(*header)); > +> > > if (!nskb) { > +> > > > solos_pop(vcc, skb); > +> > > > return -ENOMEM; > +> > > } > +> > > if (skb->truesize !=3D nskb->truesize) > +> > > > atm_force_charge(vcc, nskb->truesize - skb->truesize); > +=20 > +> > > dev_kfree_skb_any(skb); > +> > > skb =3D nskb; > > > } > =20 > > > header =3D (void *)skb_push(skb, sizeof(*header)); Simon, did you ever test this? Can you still (tell me how to) reproduce the original problem? I think that sending on br2684 was necessary but not sufficient...? --=20 David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation --=-3KX7VBrR3KGKQBEzboQe Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIISjjCCBicw ggUPoAMCAQICAw3vNzANBgkqhkiG9w0BAQUFADCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0 YXJ0Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcx ODA2BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENB MB4XDTE1MDUwNTA5NDM0MVoXDTE2MDUwNTA5NTMzNlowQjEcMBoGA1UEAwwTZHdtdzJAaW5mcmFk ZWFkLm9yZzEiMCAGCSqGSIb3DQEJARYTZHdtdzJAaW5mcmFkZWFkLm9yZzCCASIwDQYJKoZIhvcN AQEBBQADggEPADCCAQoCggEBAMkbm9kPbx1j/X4RVyf/pPKSYwelcco69TvnQQbKM8m8xkWjXJI1 jpJ1jMaGUZGFToINMSZi7lZawUozudWbXSKy1SikENSTJHffsdRAIlsp+hR8vWvjsKUry6sEdqPG 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