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, 64 insertions, 0 deletions

diff --git a/include/net/icmp.h b/include/net/icmp.h
new file mode 100644
index 000000000..935ee13d9
--- /dev/null
+++ b/include/net/icmp.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Definitions for the ICMP module.
+ *
+ * Version:	@(#)icmp.h	1.0.4	05/13/93
+ *
+ * Authors:	Ross Biro
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ */
+#ifndef _ICMP_H
+#define	_ICMP_H
+
+#include <linux/icmp.h>
+
+#include <net/inet_sock.h>
+#include <net/snmp.h>
+#include <net/ip.h>
+
+struct icmp_err {
+  int		errno;
+  unsigned int	fatal:1;
+};
+
+extern const struct icmp_err icmp_err_convert[];
+#define ICMP_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.icmp_statistics, field)
+#define __ICMP_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.icmp_statistics, field)
+#define ICMPMSGOUT_INC_STATS(net, field)	SNMP_INC_STATS_ATOMIC_LONG((net)->mib.icmpmsg_statistics, field+256)
+#define ICMPMSGIN_INC_STATS(net, field)		SNMP_INC_STATS_ATOMIC_LONG((net)->mib.icmpmsg_statistics, field)
+
+struct dst_entry;
+struct net_proto_family;
+struct sk_buff;
+struct net;
+
+void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
+		 const struct inet_skb_parm *parm);
+static inline void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
+{
+	__icmp_send(skb_in, type, code, info, IPCB(skb_in));
+}
+
+#if IS_ENABLED(CONFIG_NF_NAT)
+void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info);
+#else
+static inline void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info)
+{
+	struct inet_skb_parm parm;
+
+	memset(&parm, 0, sizeof(parm));
+	__icmp_send(skb_in, type, code, info, &parm);
+}
+#endif
+
+int icmp_rcv(struct sk_buff *skb);
+int icmp_err(struct sk_buff *skb, u32 info);
+int icmp_init(void);
+void icmp_out_count(struct net *net, unsigned char type);
+bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr);
+
+#endif	/* _ICMP_H */