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, 148 insertions, 0 deletions

diff --git a/net/ieee802154/netlink.c b/net/ieee802154/netlink.c
new file mode 100644
index 000000000..cacad2134
--- /dev/null
+++ b/net/ieee802154/netlink.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Netlink interface for IEEE 802.15.4 stack
+ *
+ * Copyright 2007, 2008 Siemens AG
+ *
+ * Written by:
+ * Sergey Lapin <slapin@ossfans.org>
+ * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
+ * Maxim Osipov <maxim.osipov@siemens.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <net/genetlink.h>
+#include <linux/nl802154.h>
+
+#include "ieee802154.h"
+
+static unsigned int ieee802154_seq_num;
+static DEFINE_SPINLOCK(ieee802154_seq_lock);
+
+/* Requests to userspace */
+struct sk_buff *ieee802154_nl_create(int flags, u8 req)
+{
+	void *hdr;
+	struct sk_buff *msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	unsigned long f;
+
+	if (!msg)
+		return NULL;
+
+	spin_lock_irqsave(&ieee802154_seq_lock, f);
+	hdr = genlmsg_put(msg, 0, ieee802154_seq_num++,
+			  &nl802154_family, flags, req);
+	spin_unlock_irqrestore(&ieee802154_seq_lock, f);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return NULL;
+	}
+
+	return msg;
+}
+
+int ieee802154_nl_mcast(struct sk_buff *msg, unsigned int group)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(msg);
+	void *hdr = genlmsg_data(nlmsg_data(nlh));
+
+	genlmsg_end(msg, hdr);
+
+	return genlmsg_multicast(&nl802154_family, msg, 0, group, GFP_ATOMIC);
+}
+
+struct sk_buff *ieee802154_nl_new_reply(struct genl_info *info,
+					int flags, u8 req)
+{
+	void *hdr;
+	struct sk_buff *msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+
+	if (!msg)
+		return NULL;
+
+	hdr = genlmsg_put_reply(msg, info,
+				&nl802154_family, flags, req);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return NULL;
+	}
+
+	return msg;
+}
+
+int ieee802154_nl_reply(struct sk_buff *msg, struct genl_info *info)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(msg);
+	void *hdr = genlmsg_data(nlmsg_data(nlh));
+
+	genlmsg_end(msg, hdr);
+
+	return genlmsg_reply(msg, info);
+}
+
+static const struct genl_small_ops ieee802154_ops[] = {
+	/* see nl-phy.c */
+	IEEE802154_DUMP(IEEE802154_LIST_PHY, ieee802154_list_phy,
+			ieee802154_dump_phy),
+	IEEE802154_OP(IEEE802154_ADD_IFACE, ieee802154_add_iface),
+	IEEE802154_OP(IEEE802154_DEL_IFACE, ieee802154_del_iface),
+	/* see nl-mac.c */
+	IEEE802154_OP(IEEE802154_ASSOCIATE_REQ, ieee802154_associate_req),
+	IEEE802154_OP(IEEE802154_ASSOCIATE_RESP, ieee802154_associate_resp),
+	IEEE802154_OP(IEEE802154_DISASSOCIATE_REQ, ieee802154_disassociate_req),
+	IEEE802154_OP(IEEE802154_SCAN_REQ, ieee802154_scan_req),
+	IEEE802154_OP(IEEE802154_START_REQ, ieee802154_start_req),
+	IEEE802154_DUMP(IEEE802154_LIST_IFACE, ieee802154_list_iface,
+			ieee802154_dump_iface),
+	IEEE802154_OP(IEEE802154_SET_MACPARAMS, ieee802154_set_macparams),
+	IEEE802154_OP(IEEE802154_LLSEC_GETPARAMS, ieee802154_llsec_getparams),
+	IEEE802154_OP(IEEE802154_LLSEC_SETPARAMS, ieee802154_llsec_setparams),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_KEY, NULL,
+			     ieee802154_llsec_dump_keys),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_ADD_KEY, ieee802154_llsec_add_key),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_DEL_KEY, ieee802154_llsec_del_key),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_DEV, NULL,
+			     ieee802154_llsec_dump_devs),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_ADD_DEV, ieee802154_llsec_add_dev),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_DEL_DEV, ieee802154_llsec_del_dev),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_DEVKEY, NULL,
+			     ieee802154_llsec_dump_devkeys),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_ADD_DEVKEY, ieee802154_llsec_add_devkey),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_DEL_DEVKEY, ieee802154_llsec_del_devkey),
+	IEEE802154_DUMP_PRIV(IEEE802154_LLSEC_LIST_SECLEVEL, NULL,
+			     ieee802154_llsec_dump_seclevels),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_ADD_SECLEVEL,
+			      ieee802154_llsec_add_seclevel),
+	IEEE802154_OP_RELAXED(IEEE802154_LLSEC_DEL_SECLEVEL,
+			      ieee802154_llsec_del_seclevel),
+};
+
+static const struct genl_multicast_group ieee802154_mcgrps[] = {
+	[IEEE802154_COORD_MCGRP] = { .name = IEEE802154_MCAST_COORD_NAME, },
+	[IEEE802154_BEACON_MCGRP] = { .name = IEEE802154_MCAST_BEACON_NAME, },
+};
+
+struct genl_family nl802154_family __ro_after_init = {
+	.hdrsize	= 0,
+	.name		= IEEE802154_NL_NAME,
+	.version	= 1,
+	.maxattr	= IEEE802154_ATTR_MAX,
+	.policy		= ieee802154_policy,
+	.module		= THIS_MODULE,
+	.small_ops	= ieee802154_ops,
+	.n_small_ops	= ARRAY_SIZE(ieee802154_ops),
+	.resv_start_op	= IEEE802154_LLSEC_DEL_SECLEVEL + 1,
+	.mcgrps		= ieee802154_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(ieee802154_mcgrps),
+};
+
+int __init ieee802154_nl_init(void)
+{
+	return genl_register_family(&nl802154_family);
+}
+
+void ieee802154_nl_exit(void)
+{
+	genl_unregister_family(&nl802154_family);
+}