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, 70 insertions, 0 deletions

diff --git a/drivers/net/phy/phy-caps.h b/drivers/net/phy/phy-caps.h
new file mode 100644
index 000000000..421088e6f
--- /dev/null
+++ b/drivers/net/phy/phy-caps.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * link caps internal header, for link modes <-> capabilities <-> interfaces
+ * conversions.
+ */
+
+#ifndef __PHY_CAPS_H
+#define __PHY_CAPS_H
+
+#include <linux/ethtool.h>
+#include <linux/phy.h>
+
+enum {
+	LINK_CAPA_10HD = 0,
+	LINK_CAPA_10FD,
+	LINK_CAPA_100HD,
+	LINK_CAPA_100FD,
+	LINK_CAPA_1000HD,
+	LINK_CAPA_1000FD,
+	LINK_CAPA_2500FD,
+	LINK_CAPA_5000FD,
+	LINK_CAPA_10000FD,
+	LINK_CAPA_20000FD,
+	LINK_CAPA_25000FD,
+	LINK_CAPA_40000FD,
+	LINK_CAPA_50000FD,
+	LINK_CAPA_56000FD,
+	LINK_CAPA_80000FD,
+	LINK_CAPA_100000FD,
+	LINK_CAPA_200000FD,
+	LINK_CAPA_400000FD,
+	LINK_CAPA_800000FD,
+	LINK_CAPA_1600000FD,
+
+	__LINK_CAPA_MAX,
+};
+
+#define LINK_CAPA_ALL	GENMASK((__LINK_CAPA_MAX - 1), 0)
+
+struct link_capabilities {
+	int speed;
+	unsigned int duplex;
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(linkmodes);
+};
+
+int __init phy_caps_init(void);
+
+size_t phy_caps_speeds(unsigned int *speeds, size_t size,
+		       unsigned long *linkmodes);
+void phy_caps_linkmode_max_speed(u32 max_speed, unsigned long *linkmodes);
+bool phy_caps_valid(int speed, int duplex, const unsigned long *linkmodes);
+void phy_caps_linkmodes(unsigned long caps, unsigned long *linkmodes);
+unsigned long phy_caps_from_interface(phy_interface_t interface);
+
+const struct link_capabilities *
+phy_caps_lookup_by_linkmode(const unsigned long *linkmodes);
+
+const struct link_capabilities *
+phy_caps_lookup_by_linkmode_rev(const unsigned long *linkmodes, bool fdx_only);
+
+const struct link_capabilities *
+phy_caps_lookup(int speed, unsigned int duplex, const unsigned long *supported,
+		bool exact);
+
+void phy_caps_medium_get_supported(unsigned long *supported,
+				   enum ethtool_link_medium medium,
+				   int lanes);
+u32 phy_caps_mediums_from_linkmodes(unsigned long *linkmodes);
+
+#endif /* __PHY_CAPS_H */