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, 97 insertions, 0 deletions

diff --git a/net/sunrpc/netlink.c b/net/sunrpc/netlink.c
new file mode 100644
index 000000000..ce09ecc0f
--- /dev/null
+++ b/net/sunrpc/netlink.c
@@ -0,0 +1,97 @@
+// 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 source */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "netlink.h"
+
+#include <uapi/linux/sunrpc_netlink.h>
+
+/* Common nested types */
+const struct nla_policy sunrpc_ip_map_nl_policy[SUNRPC_A_IP_MAP_EXPIRY + 1] = {
+	[SUNRPC_A_IP_MAP_SEQNO] = { .type = NLA_U64, },
+	[SUNRPC_A_IP_MAP_CLASS] = { .type = NLA_NUL_STRING, },
+	[SUNRPC_A_IP_MAP_ADDR] = { .type = NLA_NUL_STRING, },
+	[SUNRPC_A_IP_MAP_DOMAIN] = { .type = NLA_NUL_STRING, },
+	[SUNRPC_A_IP_MAP_NEGATIVE] = { .type = NLA_FLAG, },
+	[SUNRPC_A_IP_MAP_EXPIRY] = { .type = NLA_U64, },
+};
+
+const struct nla_policy sunrpc_unix_gid_nl_policy[SUNRPC_A_UNIX_GID_EXPIRY + 1] = {
+	[SUNRPC_A_UNIX_GID_SEQNO] = { .type = NLA_U64, },
+	[SUNRPC_A_UNIX_GID_UID] = { .type = NLA_U32, },
+	[SUNRPC_A_UNIX_GID_GIDS] = { .type = NLA_U32, },
+	[SUNRPC_A_UNIX_GID_NEGATIVE] = { .type = NLA_FLAG, },
+	[SUNRPC_A_UNIX_GID_EXPIRY] = { .type = NLA_U64, },
+};
+
+/* SUNRPC_CMD_IP_MAP_SET_REQS - do */
+static const struct nla_policy sunrpc_ip_map_set_reqs_nl_policy[SUNRPC_A_IP_MAP_REQS_REQUESTS + 1] = {
+	[SUNRPC_A_IP_MAP_REQS_REQUESTS] = NLA_POLICY_NESTED(sunrpc_ip_map_nl_policy),
+};
+
+/* SUNRPC_CMD_UNIX_GID_SET_REQS - do */
+static const struct nla_policy sunrpc_unix_gid_set_reqs_nl_policy[SUNRPC_A_UNIX_GID_REQS_REQUESTS + 1] = {
+	[SUNRPC_A_UNIX_GID_REQS_REQUESTS] = NLA_POLICY_NESTED(sunrpc_unix_gid_nl_policy),
+};
+
+/* SUNRPC_CMD_CACHE_FLUSH - do */
+static const struct nla_policy sunrpc_cache_flush_nl_policy[SUNRPC_A_CACHE_FLUSH_MASK + 1] = {
+	[SUNRPC_A_CACHE_FLUSH_MASK] = NLA_POLICY_MASK(NLA_U32, 0x3),
+};
+
+/* Ops table for sunrpc */
+static const struct genl_split_ops sunrpc_nl_ops[] = {
+	{
+		.cmd	= SUNRPC_CMD_IP_MAP_GET_REQS,
+		.dumpit	= sunrpc_nl_ip_map_get_reqs_dumpit,
+		.flags	= GENL_ADMIN_PERM | GENL_CMD_CAP_DUMP,
+	},
+	{
+		.cmd		= SUNRPC_CMD_IP_MAP_SET_REQS,
+		.doit		= sunrpc_nl_ip_map_set_reqs_doit,
+		.policy		= sunrpc_ip_map_set_reqs_nl_policy,
+		.maxattr	= SUNRPC_A_IP_MAP_REQS_REQUESTS,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd	= SUNRPC_CMD_UNIX_GID_GET_REQS,
+		.dumpit	= sunrpc_nl_unix_gid_get_reqs_dumpit,
+		.flags	= GENL_ADMIN_PERM | GENL_CMD_CAP_DUMP,
+	},
+	{
+		.cmd		= SUNRPC_CMD_UNIX_GID_SET_REQS,
+		.doit		= sunrpc_nl_unix_gid_set_reqs_doit,
+		.policy		= sunrpc_unix_gid_set_reqs_nl_policy,
+		.maxattr	= SUNRPC_A_UNIX_GID_REQS_REQUESTS,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= SUNRPC_CMD_CACHE_FLUSH,
+		.doit		= sunrpc_nl_cache_flush_doit,
+		.policy		= sunrpc_cache_flush_nl_policy,
+		.maxattr	= SUNRPC_A_CACHE_FLUSH_MASK,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+};
+
+static const struct genl_multicast_group sunrpc_nl_mcgrps[] = {
+	[SUNRPC_NLGRP_NONE] = { "none", },
+	[SUNRPC_NLGRP_EXPORTD] = { "exportd", },
+};
+
+struct genl_family sunrpc_nl_family __ro_after_init = {
+	.name		= SUNRPC_FAMILY_NAME,
+	.version	= SUNRPC_FAMILY_VERSION,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.module		= THIS_MODULE,
+	.split_ops	= sunrpc_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(sunrpc_nl_ops),
+	.mcgrps		= sunrpc_nl_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(sunrpc_nl_mcgrps),
+};