Parts of rpc_free_client() were recently moved to
a separate rpc_free_clent_work(). This introduced
a use-after-free as rpc_clnt_remove_pipedir() calls
rpc_net_ns(), and that uses clnt->cl_xprt which has already
been freed.
So move the call to xprt_put() after the call to
rpc_clnt_remove_pipedir().
Reported-by: syzbot+22b5ef302c7c40d94ea8@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 7c4310ff5642 ("SUNRPC: defer slow parts of rpc_free_client() to a workqueue.")
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
net/sunrpc/clnt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 8350d3a2e9a7..8d3972ea688b 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -890,6 +890,7 @@ static void rpc_free_client_work(struct work_struct *work)
*/
rpc_clnt_debugfs_unregister(clnt);
rpc_clnt_remove_pipedir(clnt);
+ xprt_put(rcu_dereference_raw(clnt->cl_xprt));
kfree(clnt);
rpciod_down();
@@ -907,7 +908,6 @@ rpc_free_client(struct rpc_clnt *clnt)
rpc_unregister_client(clnt);
rpc_free_iostats(clnt->cl_metrics);
clnt->cl_metrics = NULL;
- xprt_put(rcu_dereference_raw(clnt->cl_xprt));
xprt_iter_destroy(&clnt->cl_xpi);
put_cred(clnt->cl_cred);
rpc_free_clid(clnt);
--
2.26.2
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