From 9759a98b974b29570dd78f676454bb1157274193 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Wed, 7 Sep 2022 09:25:00 +0000
Subject: [PATCH] SUNRPC: Reinitialise the backchannel request buffers before
reuse
stable inclusion
from stable-v4.19.256
commit 1429b2fa358c6fbd5e037edac59e20fa02aa783e
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ
CVE: NA
--------------------------------
commit 6622e3a73112fc336c1c2c582428fb5ef18e456a upstream.
When we're reusing the backchannel requests instead of freeing them,
then we should reinitialise any values of the send/receive xdr_bufs so
that they reflect the available space.
Fixes: 0d2a970d0ae5 ("SUNRPC: Fix a backchannel race")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
---
net/sunrpc/backchannel_rqst.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 3c15a99b9700..e41427e1740d 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -69,6 +69,17 @@ static void xprt_free_allocation(struct rpc_rqst *req)
kfree(req);
}
+static void xprt_bc_reinit_xdr_buf(struct xdr_buf *buf)
+{
+ buf->head[0].iov_len = PAGE_SIZE;
+ buf->tail[0].iov_len = 0;
+ buf->pages = NULL;
+ buf->page_len = 0;
+ buf->flags = 0;
+ buf->len = 0;
+ buf->buflen = PAGE_SIZE;
+}
+
static int xprt_alloc_xdr_buf(struct xdr_buf *buf, gfp_t gfp_flags)
{
struct page *page;
@@ -291,6 +302,9 @@ void xprt_free_bc_rqst(struct rpc_rqst *req)
*/
spin_lock_bh(&xprt->bc_pa_lock);
if (xprt_need_to_requeue(xprt)) {
+ xprt_bc_reinit_xdr_buf(&req->rq_snd_buf);
+ xprt_bc_reinit_xdr_buf(&req->rq_rcv_buf);
+ req->rq_rcv_buf.len = PAGE_SIZE;
list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);
xprt->bc_alloc_count++;
req = NULL;
--
GitLab