selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/include/net/fib_notifier.h b/include/net/fib_notifier.h
new file mode 100644
index 000000000..48aad6128
--- /dev/null
+++ b/include/net/fib_notifier.h
@@ -0,0 +1,51 @@
+#ifndef __NET_FIB_NOTIFIER_H
+#define __NET_FIB_NOTIFIER_H
+
+#include <linux/types.h>
+#include <linux/notifier.h>
+#include <net/net_namespace.h>
+
+struct module;
+
+struct fib_notifier_info {
+	int family;
+	struct netlink_ext_ack  *extack;
+};
+
+enum fib_event_type {
+	FIB_EVENT_ENTRY_REPLACE,
+	FIB_EVENT_ENTRY_APPEND,
+	FIB_EVENT_ENTRY_ADD,
+	FIB_EVENT_ENTRY_DEL,
+	FIB_EVENT_RULE_ADD,
+	FIB_EVENT_RULE_DEL,
+	FIB_EVENT_NH_ADD,
+	FIB_EVENT_NH_DEL,
+	FIB_EVENT_VIF_ADD,
+	FIB_EVENT_VIF_DEL,
+};
+
+struct fib_notifier_ops {
+	int family;
+	struct list_head list;
+	unsigned int (*fib_seq_read)(const struct net *net);
+	int (*fib_dump)(struct net *net, struct notifier_block *nb,
+			struct netlink_ext_ack *extack);
+	struct module *owner;
+	struct rcu_head rcu;
+};
+
+int call_fib_notifier(struct notifier_block *nb,
+		      enum fib_event_type event_type,
+		      struct fib_notifier_info *info);
+int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
+		       struct fib_notifier_info *info);
+int register_fib_notifier(struct net *net, struct notifier_block *nb,
+			  void (*cb)(struct notifier_block *nb),
+			  struct netlink_ext_ack *extack);
+int unregister_fib_notifier(struct net *net, struct notifier_block *nb);
+struct fib_notifier_ops *
+fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net);
+void fib_notifier_ops_unregister(struct fib_notifier_ops *ops);
+
+#endif