On Wed, 12 Mar 2014 10:05:24 -0400 Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote: > > On Mar 12, 2014, at 9:33, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > On Sat, 08 Mar 2014 14:13:44 -0600 > > Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > >> On 3/8/2014 1:20 PM, Steve Wise wrote: > >>> > >>>> I removed your change and started debugging original crash that > >>>> happens on top-o-tree. Seems like rq_next_pages is screwed > >>>> up. It should always be >= rq_respages, yes? I added a > >>>> BUG_ON() to assert this in rdma_read_xdr() we hit the BUG_ON(). > >>>> Look > >>>> > >>>> crash> svc_rqst.rq_next_page 0xffff8800b84e6000 > >>>> rq_next_page = 0xffff8800b84e6228 > >>>> crash> svc_rqst.rq_respages 0xffff8800b84e6000 > >>>> rq_respages = 0xffff8800b84e62a8 > >>>> > >>>> Any ideas Bruce/Tom? > >>>> > >>> > >>> Guys, the patch below seems to fix the problem. Dunno if it is > >>> correct though. What do you think? > >>> > >>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > >>> b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > >>> index 0ce7552..6d62411 100644 > >>> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > >>> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > >>> @@ -90,6 +90,7 @@ static void rdma_build_arg_xdr(struct svc_rqst > >>> *rqstp, sge_no++; > >>> } > >>> rqstp->rq_respages = &rqstp->rq_pages[sge_no]; > >>> + rqstp->rq_next_page = rqstp->rq_respages; > >>> > >>> /* We should never run out of SGE because the limit is > >>> defined to > >>> * support the max allowed RPC data length > >>> @@ -276,6 +277,7 @@ static int fast_reg_read_chunks(struct > >>> svcxprt_rdma *xprt, > >>> > >>> /* rq_respages points one past arg pages */ > >>> rqstp->rq_respages = &rqstp->rq_arg.pages[page_no]; > >>> + rqstp->rq_next_page = rqstp->rq_respages; > >>> > >>> /* Create the reply and chunk maps */ > >>> offset = 0; > >>> > >>> > >> > >> While this patch avoids the crashing, it apparently isn't > >> correct...I'm getting IO errors reading files over the mount. :) > >> > > > > I hit the same oops and tested your patch and it seems to have fixed > > that particular panic, but I still see a bunch of other mem > > corruption oopses even with it. I'll look more closely at that when > > I get some time. > > > > FWIW, I can easily reproduce that by simply doing something like: > > > > $ dd if=/dev/urandom of=/file/on/nfsordma/mount bs=4k count=1 > > > > I'm not sure why you're not seeing any panics with your patch in > > place. Perhaps it's due to hw differences between our test rigs. > > > > The EIO problem that you're seeing is likely the same client bug > > that Chuck recently fixed in this patch: > > > > [PATCH 2/8] SUNRPC: Fix large reads on NFS/RDMA > > > > AIUI, Trond is merging that set for 3.15, so I'd make sure your > > client has those patches when testing. > > > > Nothing is in my queue yet. > Doh! Any reason not to merge that set from Chuck? They do fix a couple of nasty client bugs... -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
