[lxc-devel] [PATCH 1/3] lxc-start: fix the container leak when daemonize

[Qiang Huang]

When start container with daemon model, we'll have a new daemon
process in lxcapi_start, whose c->numthreads is 2, inherited
from his father, and his father's return and lxc_container_put
won't affect son's numthreads. So when daemon stops, he only
did on lxc_container_put, the lxc_container will leak.

Actually, lxc_container_get only works for mulit-threads cases,
here we did fork, and don't need to hold container count to
protect anything, so just remove it.

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
Signed-off-by: Qiang Huang <h.huangqiang at huawei.com>
---
 src/lxc/lxccontainer.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 368cb46..d020918 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -589,15 +589,11 @@ static bool lxcapi_start(struct lxc_container *c, int useinit, char * const argv
 	* while container is running...
 	*/
 	if (daemonize) {
-		if (!lxc_container_get(c))
-			return false;
 		lxc_monitord_spawn(c->config_path);
 
 		pid_t pid = fork();
-		if (pid < 0) {
-			lxc_container_put(c);
+		if (pid < 0)
 			return false;
-		}
 		if (pid != 0)
 			return wait_on_daemonized_start(c, pid);
 
@@ -639,6 +635,10 @@ reboot:
 	}
 
 	if (daemonize) {
+		/* When daemon was forked, it inherited parent's
+		 * lxc_container, so here need a put to free
+		 * lxc_container.
+		 */
 		lxc_container_put(c);
 		exit (ret == 0 ? true : false);
 	} else {
-- 
1.8.3