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, 71 insertions, 0 deletions

diff --git a/tools/perf/util/s390-cpumsf-kernel.h b/tools/perf/util/s390-cpumsf-kernel.h
new file mode 100644
index 000000000..de8c7ad0e
--- /dev/null
+++ b/tools/perf/util/s390-cpumsf-kernel.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Auxtrace support for s390 CPU measurement sampling facility
+ *
+ *  Copyright IBM Corp. 2018
+ *  Author(s): Hendrik Brueckner <brueckner@linux.ibm.com>
+ *	       Thomas Richter <tmricht@linux.ibm.com>
+ */
+#ifndef S390_CPUMSF_KERNEL_H
+#define S390_CPUMSF_KERNEL_H
+
+#define	S390_CPUMSF_PAGESZ	4096	/* Size of sample block units */
+#define	S390_CPUMSF_DIAG_DEF_FIRST	0x8001	/* Diagnostic entry lowest id */
+
+struct hws_basic_entry {
+	unsigned int def:16;	    /* 0-15  Data Entry Format		 */
+	unsigned int R:4;	    /* 16-19 reserved			 */
+	unsigned int U:4;	    /* 20-23 Number of unique instruct.  */
+	unsigned int z:2;	    /* zeros				 */
+	unsigned int T:1;	    /* 26 PSW DAT mode			 */
+	unsigned int W:1;	    /* 27 PSW wait state		 */
+	unsigned int P:1;	    /* 28 PSW Problem state		 */
+	unsigned int AS:2;	    /* 29-30 PSW address-space control	 */
+	unsigned int I:1;	    /* 31 entry valid or invalid	 */
+	unsigned int CL:2;	    /* 32-33 Configuration Level	 */
+	unsigned int:14;
+	unsigned int prim_asn:16;   /* primary ASN			 */
+	unsigned long long ia;	    /* Instruction Address		 */
+	unsigned long long gpp;     /* Guest Program Parameter		 */
+	unsigned long long hpp;     /* Host Program Parameter		 */
+};
+
+struct hws_diag_entry {
+	unsigned int def:16;	    /* 0-15  Data Entry Format		 */
+	unsigned int R:15;	    /* 16-19 and 20-30 reserved		 */
+	unsigned int I:1;	    /* 31 entry valid or invalid	 */
+	u8	     data[];	    /* Machine-dependent sample data	 */
+};
+
+struct hws_combined_entry {
+	struct hws_basic_entry	basic;	/* Basic-sampling data entry */
+	struct hws_diag_entry	diag;	/* Diagnostic-sampling data entry */
+};
+
+struct hws_trailer_entry {
+	union {
+		struct {
+			unsigned int f:1;	/* 0 - Block Full Indicator   */
+			unsigned int a:1;	/* 1 - Alert request control  */
+			unsigned int t:1;	/* 2 - Timestamp format	      */
+			unsigned int:29;	/* 3 - 31: Reserved	      */
+			unsigned int bsdes:16;	/* 32-47: size of basic SDE   */
+			unsigned int dsdes:16;	/* 48-63: size of diagnostic SDE */
+		};
+		unsigned long long flags;	/* 0 - 64: All indicators     */
+	};
+	unsigned long long overflow;	 /* 64 - sample Overflow count	      */
+	unsigned char timestamp[16];	 /* 16 - 31 timestamp		      */
+	unsigned long long reserved1;	 /* 32 -Reserved		      */
+	unsigned long long reserved2;	 /*				      */
+	union {				 /* 48 - reserved for programming use */
+		struct {
+			unsigned long long clock_base:1; /* in progusage2 */
+			unsigned long long progusage1:63;
+			unsigned long long progusage2;
+		};
+		unsigned long long progusage[2];
+	};
+};
+
+#endif