From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754412AbdLHP4w (ORCPT ); Fri, 8 Dec 2017 10:56:52 -0500 Received: from mail-it0-f54.google.com ([209.85.214.54]:41320 "EHLO mail-it0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754309AbdLHP4o (ORCPT ); Fri, 8 Dec 2017 10:56:44 -0500 X-Google-Smtp-Source: ACJfBouaWKQSOwHq19qjxLTljdJINIgYCTfO81D5QVTrgt2+umGJ16oWDHqAhC5wSF7bWIpV6s5/og== Date: Fri, 8 Dec 2017 08:56:41 -0700 From: Jason Gunthorpe To: Alexander.Steffen@infineon.com Cc: pmenzel@molgen.mpg.de, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [Regression 4.15-rc2] New messages `tpm tpm0: A TPM error (2314) occurred continue selftest` Message-ID: <20171208155641.GA2883@ziepe.ca> References: <32b0e6c1292f4818825e9e0e9bff4d39@infineon.com> <20171207183743.GB16884@ziepe.ca> <37b47bbcce5d4cf1b1fad32576e501d4@infineon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <37b47bbcce5d4cf1b1fad32576e501d4@infineon.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 08, 2017 at 12:14:04PM +0000, Alexander.Steffen@infineon.com wrote: > Is it really that ugly? I still need delay_msec to increase the > delay each round. I can see the benefit of your suggestion when it > is important to get the timing exactly right (and also account for > time spent elsewhere, when our code might not be executing). But in > this case having delays that are approximately right (or longer than > intended) is sufficient. For timeouts like this we really need to be above the TPM specified delay in all cases, even if usleep_range selected something smaller/larger.. The only way to do that is with an absolute timeout.. > Anyway, from the log messages it is clear that tpm_msleep got called > seven times with delays of 20/40/80/160/320/640/1280ms. But still > all timestamps lie within the same second. How can this be with a > cumulated delay of ~2.5s? Yes, that does seem to be the bug, our sleep function doesn't work aynmore for some reason :| > Also, I've just noticed that despite the name tpm_msleep calls > usleep_range, not msleep. Can this have an influence? Should > tpm_msleep call msleep for longer delays, as suggested by > Documentation/timers/timers-howto.txt? This change was introduced recently and is probably the source of this regression. Jason