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, 198 insertions, 0 deletions

diff --git a/include/net/flow.h b/include/net/flow.h
new file mode 100644
index 000000000..ae9481c40
--- /dev/null
+++ b/include/net/flow.h
@@ -0,0 +1,198 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *
+ *	Generic internet FLOW.
+ *
+ */
+
+#ifndef _NET_FLOW_H
+#define _NET_FLOW_H
+
+#include <linux/in6.h>
+#include <linux/atomic.h>
+#include <linux/container_of.h>
+#include <linux/uidgid.h>
+#include <net/inet_dscp.h>
+
+struct flow_keys;
+
+/*
+ * ifindex generation is per-net namespace, and loopback is
+ * always the 1st device in ns (see net_dev_init), thus any
+ * loopback device should get ifindex 1
+ */
+
+#define LOOPBACK_IFINDEX	1
+
+struct flowi_tunnel {
+	__be64			tun_id;
+};
+
+struct flowi_common {
+	int	flowic_oif;
+	int	flowic_iif;
+	int     flowic_l3mdev;
+	__u32	flowic_mark;
+	dscp_t	flowic_dscp;
+	__u8	flowic_scope;
+	__u8	flowic_proto;
+	__u8	flowic_flags;
+#define FLOWI_FLAG_ANYSRC		0x01
+#define FLOWI_FLAG_KNOWN_NH		0x02
+#define FLOWI_FLAG_L3MDEV_OIF		0x04
+#define FLOWI_FLAG_ANY_SPORT		0x08
+	__u32	flowic_secid;
+	kuid_t  flowic_uid;
+	__u32		flowic_multipath_hash;
+	struct flowi_tunnel flowic_tun_key;
+};
+
+union flowi_uli {
+	struct {
+		__be16	dport;
+		__be16	sport;
+	} ports;
+
+	struct {
+		__u8	type;
+		__u8	code;
+	} icmpt;
+
+	__be32		gre_key;
+
+	struct {
+		__u8	type;
+	} mht;
+};
+
+struct flowi4 {
+	struct flowi_common	__fl_common;
+#define flowi4_oif		__fl_common.flowic_oif
+#define flowi4_iif		__fl_common.flowic_iif
+#define flowi4_l3mdev		__fl_common.flowic_l3mdev
+#define flowi4_mark		__fl_common.flowic_mark
+#define flowi4_dscp		__fl_common.flowic_dscp
+#define flowi4_scope		__fl_common.flowic_scope
+#define flowi4_proto		__fl_common.flowic_proto
+#define flowi4_flags		__fl_common.flowic_flags
+#define flowi4_secid		__fl_common.flowic_secid
+#define flowi4_tun_key		__fl_common.flowic_tun_key
+#define flowi4_uid		__fl_common.flowic_uid
+#define flowi4_multipath_hash	__fl_common.flowic_multipath_hash
+
+	/* (saddr,daddr) must be grouped, same order as in IP header */
+	__be32			saddr;
+	__be32			daddr;
+
+	union flowi_uli		uli;
+#define fl4_sport		uli.ports.sport
+#define fl4_dport		uli.ports.dport
+#define fl4_icmp_type		uli.icmpt.type
+#define fl4_icmp_code		uli.icmpt.code
+#define fl4_mh_type		uli.mht.type
+#define fl4_gre_key		uli.gre_key
+} __attribute__((__aligned__(BITS_PER_LONG/8)));
+
+static inline void flowi4_init_output(struct flowi4 *fl4, int oif,
+				      __u32 mark, __u8 tos, __u8 scope,
+				      __u8 proto, __u8 flags,
+				      __be32 daddr, __be32 saddr,
+				      __be16 dport, __be16 sport,
+				      kuid_t uid)
+{
+	fl4->flowi4_oif = oif;
+	fl4->flowi4_iif = LOOPBACK_IFINDEX;
+	fl4->flowi4_l3mdev = 0;
+	fl4->flowi4_mark = mark;
+	fl4->flowi4_dscp = inet_dsfield_to_dscp(tos);
+	fl4->flowi4_scope = scope;
+	fl4->flowi4_proto = proto;
+	fl4->flowi4_flags = flags;
+	fl4->flowi4_secid = 0;
+	fl4->flowi4_tun_key.tun_id = 0;
+	fl4->flowi4_uid = uid;
+	fl4->daddr = daddr;
+	fl4->saddr = saddr;
+	fl4->fl4_dport = dport;
+	fl4->fl4_sport = sport;
+	fl4->flowi4_multipath_hash = 0;
+}
+
+/* Reset some input parameters after previous lookup */
+static inline void flowi4_update_output(struct flowi4 *fl4, int oif,
+					__be32 daddr, __be32 saddr)
+{
+	fl4->flowi4_oif = oif;
+	fl4->daddr = daddr;
+	fl4->saddr = saddr;
+}
+
+
+struct flowi6 {
+	struct flowi_common	__fl_common;
+#define flowi6_oif		__fl_common.flowic_oif
+#define flowi6_iif		__fl_common.flowic_iif
+#define flowi6_l3mdev		__fl_common.flowic_l3mdev
+#define flowi6_mark		__fl_common.flowic_mark
+#define flowi6_scope		__fl_common.flowic_scope
+#define flowi6_proto		__fl_common.flowic_proto
+#define flowi6_flags		__fl_common.flowic_flags
+#define flowi6_secid		__fl_common.flowic_secid
+#define flowi6_tun_key		__fl_common.flowic_tun_key
+#define flowi6_uid		__fl_common.flowic_uid
+	struct in6_addr		daddr;
+	struct in6_addr		saddr;
+	/* Note: flowi6_dscp is encoded in flowlabel, too. */
+	__be32			flowlabel;
+	union flowi_uli		uli;
+#define fl6_sport		uli.ports.sport
+#define fl6_dport		uli.ports.dport
+#define fl6_icmp_type		uli.icmpt.type
+#define fl6_icmp_code		uli.icmpt.code
+#define fl6_mh_type		uli.mht.type
+#define fl6_gre_key		uli.gre_key
+	__u32			mp_hash;
+} __attribute__((__aligned__(BITS_PER_LONG/8)));
+
+struct flowi {
+	union {
+		struct flowi_common	__fl_common;
+		struct flowi4		ip4;
+		struct flowi6		ip6;
+	} u;
+#define flowi_oif	u.__fl_common.flowic_oif
+#define flowi_iif	u.__fl_common.flowic_iif
+#define flowi_l3mdev	u.__fl_common.flowic_l3mdev
+#define flowi_mark	u.__fl_common.flowic_mark
+#define flowi_dscp	u.__fl_common.flowic_dscp
+#define flowi_scope	u.__fl_common.flowic_scope
+#define flowi_proto	u.__fl_common.flowic_proto
+#define flowi_flags	u.__fl_common.flowic_flags
+#define flowi_secid	u.__fl_common.flowic_secid
+#define flowi_tun_key	u.__fl_common.flowic_tun_key
+#define flowi_uid	u.__fl_common.flowic_uid
+} __attribute__((__aligned__(BITS_PER_LONG/8)));
+
+static inline struct flowi *flowi4_to_flowi(struct flowi4 *fl4)
+{
+	return container_of(fl4, struct flowi, u.ip4);
+}
+
+static inline struct flowi_common *flowi4_to_flowi_common(struct flowi4 *fl4)
+{
+	return &(fl4->__fl_common);
+}
+
+static inline struct flowi *flowi6_to_flowi(struct flowi6 *fl6)
+{
+	return container_of(fl6, struct flowi, u.ip6);
+}
+
+static inline struct flowi_common *flowi6_to_flowi_common(struct flowi6 *fl6)
+{
+	return &(fl6->__fl_common);
+}
+
+__u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys);
+
+#endif