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x-ms-exchange-antispam-messagedata: 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 Content-Type: text/plain; charset="us-ascii" Content-ID: <67AB65846C59F34980D57B96AD0E83C6@eurprd04.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: AM7PR04MB7157.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: d7788f53-a138-4dd6-86aa-08d844babb10 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Aug 2020 03:40:06.4599 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: +73RCBHVi3o2VKoZu4HQmnHJY4MALGMod/8GC2ZvXzdEoozSqWm7wE/wBXjGjeHp6Ixpc7GI1cTvwyHjw0NYbg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR04MB4758 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 20-08-19 10:52:36, stern@rowland.harvard.edu wrote: > On Wed, Aug 19, 2020 at 01:31:14AM +0000, Peter Chen wrote: > > On 20-08-18 10:46:55, stern@rowland.harvard.edu wrote: > > > On Tue, Aug 18, 2020 at 10:05:51AM +0000, Peter Chen wrote: > > > > =20 > > > > > > > > > > > > diff --git a/drivers/usb/gadget/udc/core.c > > > > > > b/drivers/usb/gadget/udc/core.c index 473e74088b1f..43351b0af56= 9 > > > > > > 100644 > > > > > > --- a/drivers/usb/gadget/udc/core.c > > > > > > +++ b/drivers/usb/gadget/udc/core.c > > > > > > @@ -1386,7 +1386,6 @@ void usb_del_gadget_udc(struct usb_gadget > > > > > > *gadget) { > > > > > > usb_del_gadget(gadget); > > > > > > usb_put_gadget(gadget); > > > > > > - memset(&gadget->dev, 0x00, sizeof(gadget->dev)); > > > > >=20 > > > > > Shouldn't you do this patch earlier in the series, as the > > > > > usb_put_gadget() call could have freed the memory that is being c= leared here? > > > > >=20 > > > >=20 > > > > If I did it earlier, it would cause dwc3 break if people do 'git bi= sect', dwc3 issue is > > > > fixed at patch 5. > > >=20 > > > If you use the patch I posted earlier: > > >=20 > > > https://eur01.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F= marc.info%2F%3Fl%3Dlinux-usb%26m%3D159605415210351%26w%3D2&data=3D02%7C= 01%7Cpeter.chen%40nxp.com%7Cac0a92404ea34c230dd208d8444f83d3%7C686ea1d3bc2b= 4c6fa92cd99c5c301635%7C0%7C0%7C637334455595715503&sdata=3DwhweZozRiWD%2= B4iRFz7zvEahWAqQYkQQ8tHlRSiU%2Fj7I%3D&reserved=3D0 > > >=20 > > > instead of this one then dwc3 would continue to work correctly during= =20 > > > the intermediate stages of the series. > > >=20 > >=20 > > But at last, we don't want below at .release function > >=20 > > memset(dev, 0, sizeof(*dev)); > >=20 > > It still needs another patch to delete it after dwc3 changes, > > and it changes .release function name to usb_udc_zero_release, > > this change may also not be needed. > >=20 > > Or I only do move memory clear operation at the first patch, and > > delete it at the last patch, it could let the reader not see > > the memory clear operation at the usb_del_gadget during the patch > > series. >=20 > One way or another, the existing code is wrong. I guess the best we can= =20 > do for now is to let it remain wrong during the patch series, rather=20 > than changing it to be wrong in a different way. >=20 > To put it another way, we already run the risk of clearing memory that=20 > has been freed. The series does not make that risk any worse, and it=20 > eventually fixes the problem. >=20 > This means your patch should remain in its position at the end of the=20 > series. >=20 Thank. If you think my sequence during the patch series is OK, would you please add your reviewed-by below? https://www.spinics.net/lists/linux-usb/msg199291.html --=20 Thanks, Peter Chen=