[CRIU] [PATCH 2/2] ns: Do not reuse PROC_SELF after CLONE_VM child

[Kirill Tkhai]

Child opens PROC_SELF, populates open_proc_self_pid and exits. If parent creates
one more child with the same pid later, the new child will try to reuse PROC_SELF,
set by exited child. So, close PROC_SELF after the first child has finished.

Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 criu/namespaces.c |    7 +++++++
 criu/net.c        |    8 ++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/criu/namespaces.c b/criu/namespaces.c
index 77308ccb6..819c75dd5 100644
--- a/criu/namespaces.c
+++ b/criu/namespaces.c
@@ -1039,8 +1039,15 @@ int collect_user_ns(struct ns_id *ns, void *oarg)
 		}
 		if (waitpid(pid, &status, 0) != pid) {
 			pr_perror("Unable to wait the %d process", pid);
+			close_pid_proc();
 			return -1;
 		}
+		/*
+		 * Child opened PROC_SELF for pid. If we create one more child
+		 * with the same pid later, it will try to reuse this /proc/self.
+		 */
+		close_pid_proc();
+
 		if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 			pr_err("Can't dump nested user_ns: %x\n", status);
 			return -1;
diff --git a/criu/net.c b/criu/net.c
index ae07ff247..3afdd5a90 100644
--- a/criu/net.c
+++ b/criu/net.c
@@ -1788,14 +1788,18 @@ int prepare_net_namespaces()
 			errno = 0;
 			if (waitpid(pid, &status, 0) != pid || !WIFEXITED(status) || WEXITSTATUS(status)) {
 				pr_err("Child waiting: errno=%d, status=%d\n", errno, status);
+				close_pid_proc();
 				goto err;
 			}
+			/*
+			 * Child opened PROC_SELF for pid. If we create one more child
+			 * with the same pid later, it will try to reuse this PROC_SELF.
+			 */
+			close_pid_proc();
 		} else {
 			if (do_create_net_ns(nsid))
 				goto err;
-
 		}
-
 	}
 
 	close_service_fd(NS_FD_OFF);