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, 89 insertions, 0 deletions

diff --git a/fs/udf/udftime.c b/fs/udf/udftime.c
new file mode 100644
index 000000000..78ecc6336
--- /dev/null
+++ b/fs/udf/udftime.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: LGPL-2.0+
+/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Eggert (eggert@twinsun.com). */
+
+/*
+ * dgb 10/02/98: ripped this from glibc source to help convert timestamps
+ *               to unix time
+ *     10/04/98: added new table-based lookup after seeing how ugly
+ *               the gnu code is
+ * blf 09/27/99: ripped out all the old code and inserted new table from
+ *		 John Brockmeyer (without leap second corrections)
+ *		 rewrote udf_stamp_to_time and fixed timezone accounting in
+ *		 udf_time_to_stamp.
+ */
+
+/*
+ * We don't take into account leap seconds. This may be correct or incorrect.
+ * For more NIST information (especially dealing with leap seconds), see:
+ * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
+ */
+
+#include "udfdecl.h"
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+
+void
+udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src)
+{
+	u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
+	u16 year = le16_to_cpu(src.year);
+	uint8_t type = typeAndTimezone >> 12;
+	int16_t offset;
+
+	if (type == 1) {
+		offset = typeAndTimezone << 4;
+		/* sign extent offset */
+		offset = (offset >> 4);
+		if (offset == -2047) /* unspecified offset */
+			offset = 0;
+	} else
+		offset = 0;
+
+	dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
+			src.second);
+	dest->tv_sec -= offset * 60;
+
+	/*
+	 * Sanitize nanosecond field since reportedly some filesystems are
+	 * recorded with bogus sub-second values.
+	 */
+	if (src.centiseconds < 100 && src.hundredsOfMicroseconds < 100 &&
+	    src.microseconds < 100) {
+		dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
+			src.hundredsOfMicroseconds * 100 + src.microseconds);
+	} else {
+		dest->tv_nsec = 0;
+	}
+}
+
+void
+udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts)
+{
+	time64_t seconds;
+	int16_t offset;
+	struct tm tm;
+
+	offset = -sys_tz.tz_minuteswest;
+
+	dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
+
+	seconds = ts.tv_sec + offset * 60;
+	time64_to_tm(seconds, 0, &tm);
+	dest->year = cpu_to_le16(tm.tm_year + 1900);
+	dest->month = tm.tm_mon + 1;
+	dest->day = tm.tm_mday;
+	dest->hour = tm.tm_hour;
+	dest->minute = tm.tm_min;
+	dest->second = tm.tm_sec;
+	dest->centiseconds = ts.tv_nsec / 10000000;
+	dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
+					dest->centiseconds * 10000) / 100;
+	dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
+			      dest->hundredsOfMicroseconds * 100);
+}
+
+/* EOF */