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x-category=clean score=-100 state=0; x-google-dkim=fail (body has been altered; 2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=Y/Ybo3Ea; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=gmail.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753018AbeCETJG (ORCPT ); Mon, 5 Mar 2018 14:09:06 -0500 Received: from mail-pf0-f174.google.com ([209.85.192.174]:36040 "EHLO mail-pf0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753001AbeCETJE (ORCPT ); Mon, 5 Mar 2018 14:09:04 -0500 X-Google-Smtp-Source: AG47ELsXrtFl8DF46BjGBD2wD3WkGoHL1yvloO548wGsOtZbd9LNkC5irXfNfSkYdq8dPzOdIl95Cg== Message-ID: <1520276942.109662.9.camel@gmail.com> Subject: Re: inconsistent lock state with usbnet/asix usb ethernet and xhci From: Eric Dumazet To: Oliver Neukum , Marek Szyprowski Cc: LKML , 'Linux Samsung SOC' , Linux USB Mailing List , netdev@vger.kernel.org, Dean Jenkins Date: Mon, 05 Mar 2018 11:09:02 -0800 In-Reply-To: <1520250367.3990.9.camel@suse.com> References: <1519740421.7296.6.camel@gmail.com> <1519744167.7296.8.camel@gmail.com> <1519744400.7296.10.camel@gmail.com> <1519747675.2649.3.camel@suse.com> <02679502-cf6e-8714-e879-50a922c5d976@samsung.com> <1520250367.3990.9.camel@suse.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org X-Mailing-List: linux-usb@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Mon, 2018-03-05 at 12:46 +0100, Oliver Neukum wrote: > On Mon, 2018-03-05 at 08:45 +0100, Marek Szyprowski wrote: > > Hi Oliver, > > > > On 2018-02-27 17:07, Oliver Neukum wrote: > > > Am Dienstag, den 27.02.2018, 07:13 -0800 schrieb Eric Dumazet: > > > > On Tue, 2018-02-27 at 07:09 -0800, Eric Dumazet wrote: > > > > > > > > > > Note that for this one, it seems we also could perform stats > > > > > updates in > > > > > BH context, since skb is queued via defer_bh() > > > > > > > > > > But simplicity wins I guess. > > > > > > > > Thinking more about this, I am not sure we have any guarantee > > > > that TX > > > > and RX can not run on multiple cpus. > > > > > > > > Using an unique syncp is not going to be safe, even if we make > > > > lockdep > > > > happy enough with the local_irq save/restore. > > > > > > Unfortunately you are right. It is not guaranteed for some > > > hardware. > > > > Does it mean that the fix proposed by Eric is not the proper > > solution? > > For asix it should work, but asix is unlikely to be the only driver > with that issue. 32 bit recieves less testing nowadays. Yes, although the lockdep part could be enforced in 64bit if we really care. I will send a patch using two different sync (one for RX, one for TX)