[Devel] [PATCH hci-8.1 v3 3/5] ve: Defer ve context drop until ve is completely destroyed

[Vladimir Riabchun]

We may have a case, when VE is dead, but there are some users of it,
overlayfs superblock for example.

This user may want to use VE creds, so we need to keep ve->init_cred alive.
Drop creds in ve_destroy. We need to drop ve_nsproxy early because
ploop waits for refcount going to zero, dropping ve_nsproxy in destroy
causes CT suspend/resume hangs.

https://virtuozzo.atlassian.net/browse/VSTOR-142405
Signed-off-by: Vladimir Riabchun <vladimir.riabchun at virtuozzo.com>
---
 kernel/ve/ve.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
index d74f74ca958a..0dc3778b6ba0 100644
--- a/kernel/ve/ve.c
+++ b/kernel/ve/ve.c
@@ -377,7 +377,10 @@ static void ve_drop_context(struct ve_struct *ve)
 	rcu_assign_pointer(ve->ve_nsproxy, NULL);
 	synchronize_rcu();
 	put_nsproxy(ve_nsproxy);
+}
 
+static void ve_drop_cred(struct ve_struct *ve)
+{
 	put_cred(ve->init_cred);
 	ve->init_cred = NULL;
 }
@@ -925,6 +928,7 @@ static void ve_destroy(struct cgroup_subsys_state *css)
 {
 	struct ve_struct *ve = css_to_ve(css);
 
+	ve_drop_cred(ve);
 	free_ve_devmnts(ve);
 
 	kmapset_unlink(&ve->sysfs_perms_key, &sysfs_ve_perms_set);

-- 
2.52.0