1 files changed, 18 insertions, 1 deletions

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index c225c42e114a..077ed3a19848 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -16,6 +16,8 @@
 #include <linux/bpf-cgroup.h>
 #include <net/sock.h>
 
+#include "../cgroup/cgroup-internal.h"
+
 DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
 EXPORT_SYMBOL(cgroup_bpf_enabled_key);
 
@@ -38,6 +40,8 @@ static void cgroup_bpf_release(struct work_struct *work)
         struct bpf_prog_array *old_array;
         unsigned int type;
 
+        mutex_lock(&cgroup_mutex);
+
         for (type = 0; type < ARRAY_SIZE(cgrp->bpf.progs); type++) {
                 struct list_head *progs = &cgrp->bpf.progs[type];
                 struct bpf_prog_list *pl, *tmp;
@@ -54,10 +58,12 @@ static void cgroup_bpf_release(struct work_struct *work)
                 }
                 old_array = rcu_dereference_protected(
                                 cgrp->bpf.effective[type],
-                                percpu_ref_is_dying(&cgrp->bpf.refcnt));
+                                lockdep_is_held(&cgroup_mutex));
                 bpf_prog_array_free(old_array);
         }
 
+        mutex_unlock(&cgroup_mutex);
+
         percpu_ref_exit(&cgrp->bpf.refcnt);
         cgroup_put(cgrp);
 }
@@ -229,6 +235,9 @@ static int update_effective_progs(struct cgroup *cgrp,
         css_for_each_descendant_pre(css, &cgrp->self) {
                 struct cgroup *desc = container_of(css, struct cgroup, self);
 
+                if (percpu_ref_is_zero(&desc->bpf.refcnt))
+                        continue;
+
                 err = compute_effective_progs(desc, type, &desc->bpf.inactive);
                 if (err)
                         goto cleanup;
@@ -238,6 +247,14 @@ static int update_effective_progs(struct cgroup *cgrp,
         css_for_each_descendant_pre(css, &cgrp->self) {
                 struct cgroup *desc = container_of(css, struct cgroup, self);
 
+                if (percpu_ref_is_zero(&desc->bpf.refcnt)) {
+                        if (unlikely(desc->bpf.inactive)) {
+                                bpf_prog_array_free(desc->bpf.inactive);
+                                desc->bpf.inactive = NULL;
+                        }
+                        continue;
+                }
+
                 activate_effective_progs(desc, type, desc->bpf.inactive);
                 desc->bpf.inactive = NULL;
         }