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, 450 insertions, 0 deletions

diff --git a/net/ethtool/cabletest.c b/net/ethtool/cabletest.c
new file mode 100644
index 000000000..9c22d4c76
--- /dev/null
+++ b/net/ethtool/cabletest.c
@@ -0,0 +1,450 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/phy.h>
+#include <linux/ethtool_netlink.h>
+#include <net/netdev_lock.h>
+
+#include "common.h"
+#include "netlink.h"
+
+/* 802.3 standard allows 100 meters for BaseT cables. However longer
+ * cables might work, depending on the quality of the cables and the
+ * PHY. So allow testing for up to 150 meters.
+ */
+#define MAX_CABLE_LENGTH_CM (150 * 100)
+
+const struct nla_policy ethnl_cable_test_act_policy[] = {
+	[ETHTOOL_A_CABLE_TEST_HEADER]		=
+		NLA_POLICY_NESTED(ethnl_header_policy_phy),
+};
+
+static int ethnl_cable_test_started(struct phy_device *phydev, u8 cmd)
+{
+	struct sk_buff *skb;
+	int err = -ENOMEM;
+	void *ehdr;
+
+	skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!skb)
+		goto out;
+
+	ehdr = ethnl_bcastmsg_put(skb, cmd);
+	if (!ehdr) {
+		err = -EMSGSIZE;
+		goto out;
+	}
+
+	err = ethnl_fill_reply_header(skb, phydev->attached_dev,
+				      ETHTOOL_A_CABLE_TEST_NTF_HEADER);
+	if (err)
+		goto out;
+
+	err = nla_put_u8(skb, ETHTOOL_A_CABLE_TEST_NTF_STATUS,
+			 ETHTOOL_A_CABLE_TEST_NTF_STATUS_STARTED);
+	if (err)
+		goto out;
+
+	genlmsg_end(skb, ehdr);
+
+	return ethnl_multicast(skb, phydev->attached_dev);
+
+out:
+	nlmsg_free(skb);
+	phydev_err(phydev, "%s: Error %pe\n", __func__, ERR_PTR(err));
+
+	return err;
+}
+
+int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ethnl_req_info req_info = {};
+	const struct ethtool_phy_ops *ops;
+	struct nlattr **tb = info->attrs;
+	struct phy_device *phydev;
+	struct net_device *dev;
+	int ret;
+
+	ret = ethnl_parse_header_dev_get(&req_info,
+					 tb[ETHTOOL_A_CABLE_TEST_HEADER],
+					 genl_info_net(info), info->extack,
+					 true);
+	if (ret < 0)
+		return ret;
+
+	dev = req_info.dev;
+
+	netdev_lock_ops_compat(dev);
+	phydev = ethnl_req_get_phydev(&req_info, tb,
+				      ETHTOOL_A_CABLE_TEST_HEADER,
+				      info->extack);
+	if (IS_ERR_OR_NULL(phydev)) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	ops = ethtool_phy_ops;
+	if (!ops || !ops->start_cable_test) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out_unlock;
+
+	ret = ops->start_cable_test(phydev, info->extack);
+
+	ethnl_ops_complete(dev);
+
+	if (!ret)
+		ethnl_cable_test_started(phydev, ETHTOOL_MSG_CABLE_TEST_NTF);
+
+out_unlock:
+	netdev_unlock_ops_compat(dev);
+	ethnl_parse_header_dev_put(&req_info);
+	return ret;
+}
+
+int ethnl_cable_test_alloc(struct phy_device *phydev, u8 cmd)
+{
+	int err = -ENOMEM;
+
+	/* One TDR sample occupies 20 bytes. For a 150 meter cable,
+	 * with four pairs, around 12K is needed.
+	 */
+	phydev->skb = genlmsg_new(SZ_16K, GFP_KERNEL);
+	if (!phydev->skb)
+		goto out;
+
+	phydev->ehdr = ethnl_bcastmsg_put(phydev->skb, cmd);
+	if (!phydev->ehdr) {
+		err = -EMSGSIZE;
+		goto out;
+	}
+
+	err = ethnl_fill_reply_header(phydev->skb, phydev->attached_dev,
+				      ETHTOOL_A_CABLE_TEST_NTF_HEADER);
+	if (err)
+		goto out;
+
+	err = nla_put_u8(phydev->skb, ETHTOOL_A_CABLE_TEST_NTF_STATUS,
+			 ETHTOOL_A_CABLE_TEST_NTF_STATUS_COMPLETED);
+	if (err)
+		goto out;
+
+	phydev->nest = nla_nest_start(phydev->skb,
+				      ETHTOOL_A_CABLE_TEST_NTF_NEST);
+	if (!phydev->nest) {
+		err = -EMSGSIZE;
+		goto out;
+	}
+
+	return 0;
+
+out:
+	nlmsg_free(phydev->skb);
+	phydev->skb = NULL;
+	return err;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_alloc);
+
+void ethnl_cable_test_free(struct phy_device *phydev)
+{
+	nlmsg_free(phydev->skb);
+	phydev->skb = NULL;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_free);
+
+void ethnl_cable_test_finished(struct phy_device *phydev)
+{
+	nla_nest_end(phydev->skb, phydev->nest);
+
+	genlmsg_end(phydev->skb, phydev->ehdr);
+
+	ethnl_multicast(phydev->skb, phydev->attached_dev);
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_finished);
+
+int ethnl_cable_test_result_with_src(struct phy_device *phydev, u8 pair,
+				     u8 result, u32 src)
+{
+	struct nlattr *nest;
+	int ret = -EMSGSIZE;
+
+	nest = nla_nest_start(phydev->skb, ETHTOOL_A_CABLE_NEST_RESULT);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(phydev->skb, ETHTOOL_A_CABLE_RESULT_PAIR, pair))
+		goto err;
+	if (nla_put_u8(phydev->skb, ETHTOOL_A_CABLE_RESULT_CODE, result))
+		goto err;
+	if (src != ETHTOOL_A_CABLE_INF_SRC_UNSPEC) {
+		if (nla_put_u32(phydev->skb, ETHTOOL_A_CABLE_RESULT_SRC, src))
+			goto err;
+	}
+
+	nla_nest_end(phydev->skb, nest);
+	return 0;
+
+err:
+	nla_nest_cancel(phydev->skb, nest);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_result_with_src);
+
+int ethnl_cable_test_fault_length_with_src(struct phy_device *phydev, u8 pair,
+					   u32 cm, u32 src)
+{
+	struct nlattr *nest;
+	int ret = -EMSGSIZE;
+
+	nest = nla_nest_start(phydev->skb,
+			      ETHTOOL_A_CABLE_NEST_FAULT_LENGTH);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(phydev->skb, ETHTOOL_A_CABLE_FAULT_LENGTH_PAIR, pair))
+		goto err;
+	if (nla_put_u32(phydev->skb, ETHTOOL_A_CABLE_FAULT_LENGTH_CM, cm))
+		goto err;
+	if (src != ETHTOOL_A_CABLE_INF_SRC_UNSPEC) {
+		if (nla_put_u32(phydev->skb, ETHTOOL_A_CABLE_FAULT_LENGTH_SRC,
+				src))
+			goto err;
+	}
+
+	nla_nest_end(phydev->skb, nest);
+	return 0;
+
+err:
+	nla_nest_cancel(phydev->skb, nest);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_fault_length_with_src);
+
+static const struct nla_policy cable_test_tdr_act_cfg_policy[] = {
+	[ETHTOOL_A_CABLE_TEST_TDR_CFG_FIRST]	= { .type = NLA_U32 },
+	[ETHTOOL_A_CABLE_TEST_TDR_CFG_LAST]	= { .type = NLA_U32 },
+	[ETHTOOL_A_CABLE_TEST_TDR_CFG_STEP]	= { .type = NLA_U32 },
+	[ETHTOOL_A_CABLE_TEST_TDR_CFG_PAIR]	= { .type = NLA_U8 },
+};
+
+const struct nla_policy ethnl_cable_test_tdr_act_policy[] = {
+	[ETHTOOL_A_CABLE_TEST_TDR_HEADER]	=
+		NLA_POLICY_NESTED(ethnl_header_policy_phy),
+	[ETHTOOL_A_CABLE_TEST_TDR_CFG]		= { .type = NLA_NESTED },
+};
+
+/* CABLE_TEST_TDR_ACT */
+static int ethnl_act_cable_test_tdr_cfg(const struct nlattr *nest,
+					struct genl_info *info,
+					struct phy_tdr_config *cfg)
+{
+	struct nlattr *tb[ARRAY_SIZE(cable_test_tdr_act_cfg_policy)];
+	int ret;
+
+	cfg->first = 100;
+	cfg->step = 100;
+	cfg->last = MAX_CABLE_LENGTH_CM;
+	cfg->pair = PHY_PAIR_ALL;
+
+	if (!nest)
+		return 0;
+
+	ret = nla_parse_nested(tb,
+			       ARRAY_SIZE(cable_test_tdr_act_cfg_policy) - 1,
+			       nest, cable_test_tdr_act_cfg_policy,
+			       info->extack);
+	if (ret < 0)
+		return ret;
+
+	if (tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_FIRST])
+		cfg->first = nla_get_u32(
+			tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_FIRST]);
+
+	if (tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_LAST])
+		cfg->last = nla_get_u32(tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_LAST]);
+
+	if (tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_STEP])
+		cfg->step = nla_get_u32(tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_STEP]);
+
+	if (tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_PAIR]) {
+		cfg->pair = nla_get_u8(tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_PAIR]);
+		if (cfg->pair > ETHTOOL_A_CABLE_PAIR_D) {
+			NL_SET_ERR_MSG_ATTR(
+				info->extack,
+				tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_PAIR],
+				"invalid pair parameter");
+			return -EINVAL;
+		}
+	}
+
+	if (cfg->first > MAX_CABLE_LENGTH_CM) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_FIRST],
+				    "invalid first parameter");
+		return -EINVAL;
+	}
+
+	if (cfg->last > MAX_CABLE_LENGTH_CM) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_LAST],
+				    "invalid last parameter");
+		return -EINVAL;
+	}
+
+	if (cfg->first > cfg->last) {
+		NL_SET_ERR_MSG(info->extack, "invalid first/last parameter");
+		return -EINVAL;
+	}
+
+	if (!cfg->step) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_STEP],
+				    "invalid step parameter");
+		return -EINVAL;
+	}
+
+	if (cfg->step > (cfg->last - cfg->first)) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_STEP],
+				    "step parameter too big");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ethnl_req_info req_info = {};
+	const struct ethtool_phy_ops *ops;
+	struct nlattr **tb = info->attrs;
+	struct phy_device *phydev;
+	struct phy_tdr_config cfg;
+	struct net_device *dev;
+	int ret;
+
+	ret = ethnl_parse_header_dev_get(&req_info,
+					 tb[ETHTOOL_A_CABLE_TEST_TDR_HEADER],
+					 genl_info_net(info), info->extack,
+					 true);
+	if (ret < 0)
+		return ret;
+
+	dev = req_info.dev;
+
+	ret = ethnl_act_cable_test_tdr_cfg(tb[ETHTOOL_A_CABLE_TEST_TDR_CFG],
+					   info, &cfg);
+	if (ret)
+		goto out_dev_put;
+
+	netdev_lock_ops_compat(dev);
+	phydev = ethnl_req_get_phydev(&req_info, tb,
+				      ETHTOOL_A_CABLE_TEST_TDR_HEADER,
+				      info->extack);
+	if (IS_ERR_OR_NULL(phydev)) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	ops = ethtool_phy_ops;
+	if (!ops || !ops->start_cable_test_tdr) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out_unlock;
+
+	ret = ops->start_cable_test_tdr(phydev, info->extack, &cfg);
+
+	ethnl_ops_complete(dev);
+
+	if (!ret)
+		ethnl_cable_test_started(phydev,
+					 ETHTOOL_MSG_CABLE_TEST_TDR_NTF);
+
+out_unlock:
+	netdev_unlock_ops_compat(dev);
+out_dev_put:
+	ethnl_parse_header_dev_put(&req_info);
+	return ret;
+}
+
+int ethnl_cable_test_amplitude(struct phy_device *phydev,
+			       u8 pair, s16 mV)
+{
+	struct nlattr *nest;
+	int ret = -EMSGSIZE;
+
+	nest = nla_nest_start(phydev->skb,
+			      ETHTOOL_A_CABLE_TDR_NEST_AMPLITUDE);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(phydev->skb, ETHTOOL_A_CABLE_AMPLITUDE_PAIR, pair))
+		goto err;
+	if (nla_put_u16(phydev->skb, ETHTOOL_A_CABLE_AMPLITUDE_mV, mV))
+		goto err;
+
+	nla_nest_end(phydev->skb, nest);
+	return 0;
+
+err:
+	nla_nest_cancel(phydev->skb, nest);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_amplitude);
+
+int ethnl_cable_test_pulse(struct phy_device *phydev, u16 mV)
+{
+	struct nlattr *nest;
+	int ret = -EMSGSIZE;
+
+	nest = nla_nest_start(phydev->skb, ETHTOOL_A_CABLE_TDR_NEST_PULSE);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u16(phydev->skb, ETHTOOL_A_CABLE_PULSE_mV, mV))
+		goto err;
+
+	nla_nest_end(phydev->skb, nest);
+	return 0;
+
+err:
+	nla_nest_cancel(phydev->skb, nest);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_pulse);
+
+int ethnl_cable_test_step(struct phy_device *phydev, u32 first, u32 last,
+			  u32 step)
+{
+	struct nlattr *nest;
+	int ret = -EMSGSIZE;
+
+	nest = nla_nest_start(phydev->skb, ETHTOOL_A_CABLE_TDR_NEST_STEP);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(phydev->skb, ETHTOOL_A_CABLE_STEP_FIRST_DISTANCE,
+			first))
+		goto err;
+
+	if (nla_put_u32(phydev->skb, ETHTOOL_A_CABLE_STEP_LAST_DISTANCE, last))
+		goto err;
+
+	if (nla_put_u32(phydev->skb, ETHTOOL_A_CABLE_STEP_STEP_DISTANCE, step))
+		goto err;
+
+	nla_nest_end(phydev->skb, nest);
+	return 0;
+
+err:
+	nla_nest_cancel(phydev->skb, nest);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_step);