| Message ID | 20151012145257.3981.13852.stgit@oracle-120.nfsv4bat.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Mon, Oct 12, 2015 at 10:53:39AM -0400, Chuck Lever wrote: > Now that the NFS server advertises a maximum payload size of 1MB > for RPC/RDMA again, it crashes in svc_process_common() when NFS > client sends a 1MB NFS WRITE on an NFS/RDMA mount. > > The server has set up a 259 element array of struct page pointers > in rq_pages[] for each incoming request. The last element of the > array is NULL. > > When an incoming request has been completely received, > rdma_read_complete() attempts to set the starting page of the > incoming page vector: > > rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count]; > > and the page to use for the reply: > > rqstp->rq_respages = &rqstp->rq_arg.pages[page_no]; > > But the value of page_no has already accounted for head->hdr_count. > Thus rq_respages now points past the end of the incoming pages. > > For NFS WRITE operations smaller than the maximum, this is harmless. > But when the NFS WRITE operation is as large as the server's max > payload size, rq_respages now points at the last entry in rq_pages, > which is NULL. > > Fixes: cc9a903d915c ('svcrdma: Change maximum server payload . . .') > BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=270 > Signed-off-by: Chuck Lever <chuck.lever@oracle.com> > Reviewed-by: Sagi Grimberg <sagig@dev.mellanox.co.il> > Reviewed-by: Steve Wise <swise@opengridcomputing.com> > Reviewed-by: Shirley Ma <shirley.ma@oracle.com> > --- > > Hi Bruce- > > This is a regression in 4.3. Can you send this to Linus? OK, queuing for 4.3, thanks.--b. > > > net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > index cb51742..37b4341 100644 > --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > @@ -531,7 +531,7 @@ static int rdma_read_complete(struct svc_rqst *rqstp, > rqstp->rq_arg.page_base = head->arg.page_base; > > /* rq_respages starts after the last arg page */ > - rqstp->rq_respages = &rqstp->rq_arg.pages[page_no]; > + rqstp->rq_respages = &rqstp->rq_pages[page_no]; > rqstp->rq_next_page = rqstp->rq_respages + 1; > > /* Rebuild rq_arg head and tail. */ -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index cb51742..37b4341 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -531,7 +531,7 @@ static int rdma_read_complete(struct svc_rqst *rqstp, rqstp->rq_arg.page_base = head->arg.page_base; /* rq_respages starts after the last arg page */ - rqstp->rq_respages = &rqstp->rq_arg.pages[page_no]; + rqstp->rq_respages = &rqstp->rq_pages[page_no]; rqstp->rq_next_page = rqstp->rq_respages + 1; /* Rebuild rq_arg head and tail. */
Now that the NFS server advertises a maximum payload size of 1MB for RPC/RDMA again, it crashes in svc_process_common() when NFS client sends a 1MB NFS WRITE on an NFS/RDMA mount. The server has set up a 259 element array of struct page pointers in rq_pages[] for each incoming request. The last element of the array is NULL. When an incoming request has been completely received, rdma_read_complete() attempts to set the starting page of the incoming page vector: rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count]; and the page to use for the reply: rqstp->rq_respages = &rqstp->rq_arg.pages[page_no]; But the value of page_no has already accounted for head->hdr_count. Thus rq_respages now points past the end of the incoming pages. For NFS WRITE operations smaller than the maximum, this is harmless. But when the NFS WRITE operation is as large as the server's max payload size, rq_respages now points at the last entry in rq_pages, which is NULL. Fixes: cc9a903d915c ('svcrdma: Change maximum server payload . . .') BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=270 Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@dev.mellanox.co.il> Reviewed-by: Steve Wise <swise@opengridcomputing.com> Reviewed-by: Shirley Ma <shirley.ma@oracle.com> --- Hi Bruce- This is a regression in 4.3. Can you send this to Linus? net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html