Return-Path: Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: GSS sequence number window From: Chuck Lever In-Reply-To: <20170606194158.GG13376@fieldses.org> Date: Tue, 6 Jun 2017 15:45:59 -0400 Cc: Benjamin Coddington , Linux NFS Mailing List Message-Id: <4D542D55-DCBA-4838-9DB2-B76B4068783E@oracle.com> References: <63736845-2BD3-4EE1-AC12-0BD21A9ABEF2@oracle.com> <20170530193419.GA9371@fieldses.org> <20170531192231.GA23526@fieldses.org> <28665890-C74A-4319-B42E-475393821EC7@oracle.com> <20170606194158.GG13376@fieldses.org> To: "J. Bruce Fields" List-ID: > On Jun 6, 2017, at 3:41 PM, J. Bruce Fields wrote: > > On Tue, Jun 06, 2017 at 03:35:23PM -0400, Chuck Lever wrote: >> I filed https://bugzilla.linux-nfs.org/show_bug.cgi?id=306 >> >> To check memory allocation latency, I could always construct >> a framework around kmalloc and alloc_page. >> >> >> I've also found some bad behavior around proto=rdma,sec=krb5i. >> When I run a heavy I/O workload (fio, for example), every so >> often a read operation fails with EIO. I dug into it a little >> and MIC verification fails for these replies on the client. > > Do we still have the problem that the read data can change between the > time we calculate the MIC and the time we transmit the data to the > client? I don't see a problem with krb5p, which, if IIUC, would also fall victim to this situation, unless there is much stricter request serialization going on with krb5p. Even so, how would I detect if this issue was present? > --b. > >> >> I filed https://bugzilla.linux-nfs.org/show_bug.cgi?id=307 >> to document this second issue. >> >> I'm not sure what a next step would be. My suspicion is that >> either the server or the client is mishandling the RPC reply >> buffer, which causes the checksums to be different. Not sure >> why this would be so intermittent, though. -- Chuck Lever