ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/net/sunrpc/netlink.h b/net/sunrpc/netlink.h
new file mode 100644
index 000000000..2c1012303
--- /dev/null
+++ b/net/sunrpc/netlink.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/sunrpc_cache.yaml */
+/* YNL-GEN kernel header */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#ifndef _LINUX_SUNRPC_GEN_H
+#define _LINUX_SUNRPC_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/sunrpc_netlink.h>
+
+/* Common nested types */
+extern const struct nla_policy sunrpc_ip_map_nl_policy[SUNRPC_A_IP_MAP_EXPIRY + 1];
+extern const struct nla_policy sunrpc_unix_gid_nl_policy[SUNRPC_A_UNIX_GID_EXPIRY + 1];
+
+int sunrpc_nl_ip_map_get_reqs_dumpit(struct sk_buff *skb,
+				     struct netlink_callback *cb);
+int sunrpc_nl_ip_map_set_reqs_doit(struct sk_buff *skb, struct genl_info *info);
+int sunrpc_nl_unix_gid_get_reqs_dumpit(struct sk_buff *skb,
+				       struct netlink_callback *cb);
+int sunrpc_nl_unix_gid_set_reqs_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int sunrpc_nl_cache_flush_doit(struct sk_buff *skb, struct genl_info *info);
+
+enum {
+	SUNRPC_NLGRP_NONE,
+	SUNRPC_NLGRP_EXPORTD,
+};
+
+extern struct genl_family sunrpc_nl_family;
+
+#endif /* _LINUX_SUNRPC_GEN_H */