From: Chuck Lever chuck.lever@oracle.com
commit 15261b9126cd5bb2ad8521da49d8f5c042d904c7 upstream.
Olga K. observed that rpcrdma_marsh_req() allocates sparse pages only when it has determined that a Reply chunk is necessary. There are plenty of cases where no Reply chunk is needed, but the XDRBUF_SPARSE_PAGES flag is set. The result would be a crash in rpcrdma_inline_fixup() when it tries to copy parts of the received Reply into a missing page.
To avoid crashing, handle sparse page allocation up front.
Until XATTR support was added, this issue did not appear often because the only SPARSE_PAGES consumer always expected a reply large enough to always require a Reply chunk.
Reported-by: Olga Kornievskaia kolga@netapp.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/sunrpc/xprtrdma/rpc_rdma.c | 40 +++++++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 9 deletions(-)
--- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -183,6 +183,31 @@ rpcrdma_nonpayload_inline(const struct r r_xprt->rx_ep.rep_max_inline_recv; }
+/* ACL likes to be lazy in allocating pages. For TCP, these + * pages can be allocated during receive processing. Not true + * for RDMA, which must always provision receive buffers + * up front. + */ +static noinline int +rpcrdma_alloc_sparse_pages(struct xdr_buf *buf) +{ + struct page **ppages; + int len; + + len = buf->page_len; + ppages = buf->pages + (buf->page_base >> PAGE_SHIFT); + while (len > 0) { + if (!*ppages) + *ppages = alloc_page(GFP_NOWAIT | __GFP_NOWARN); + if (!*ppages) + return -ENOBUFS; + ppages++; + len -= PAGE_SIZE; + } + + return 0; +} + /* Split @vec on page boundaries into SGEs. FMR registers pages, not * a byte range. Other modes coalesce these SGEs into a single MR * when they can. @@ -237,15 +262,6 @@ rpcrdma_convert_iovs(struct rpcrdma_xprt ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT); page_base = offset_in_page(xdrbuf->page_base); while (len) { - /* ACL likes to be lazy in allocating pages - ACLs - * are small by default but can get huge. - */ - if (unlikely(xdrbuf->flags & XDRBUF_SPARSE_PAGES)) { - if (!*ppages) - *ppages = alloc_page(GFP_NOWAIT | __GFP_NOWARN); - if (!*ppages) - return -ENOBUFS; - } seg->mr_page = *ppages; seg->mr_offset = (char *)page_base; seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len); @@ -800,6 +816,12 @@ rpcrdma_marshal_req(struct rpcrdma_xprt __be32 *p; int ret;
+ if (unlikely(rqst->rq_rcv_buf.flags & XDRBUF_SPARSE_PAGES)) { + ret = rpcrdma_alloc_sparse_pages(&rqst->rq_rcv_buf); + if (ret) + return ret; + } + rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0); xdr_init_encode(xdr, &req->rl_hdrbuf, rdmab_data(req->rl_rdmabuf), rqst);