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, 160 insertions, 0 deletions

diff --git a/fs/xfs/xfs_message.c b/fs/xfs/xfs_message.c
new file mode 100644
index 000000000..0243e509a
--- /dev/null
+++ b/fs/xfs/xfs_message.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2011 Red Hat, Inc.  All Rights Reserved.
+ */
+
+#include "xfs_platform.h"
+#include "xfs_fs.h"
+#include "xfs_error.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+
+/*
+ * XFS logging functions
+ */
+static void
+__xfs_printk(
+	const char		*level,
+	const struct xfs_mount	*mp,
+	struct va_format	*vaf)
+{
+	if (mp && mp->m_super) {
+		printk("%sXFS (%s): %pV\n", level, mp->m_super->s_id, vaf);
+		return;
+	}
+	printk("%sXFS: %pV\n", level, vaf);
+}
+
+void
+xfs_printk_level(
+	const char *kern_level,
+	const struct xfs_mount *mp,
+	const char *fmt, ...)
+{
+	struct va_format	vaf;
+	va_list			args;
+	int			level;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	__xfs_printk(kern_level, mp, &vaf);
+
+	va_end(args);
+
+	if (!kstrtoint(kern_level, 0, &level) &&
+	    level <= LOGLEVEL_ERR &&
+	    xfs_error_level >= XFS_ERRLEVEL_HIGH)
+		xfs_stack_trace();
+}
+
+void
+_xfs_alert_tag(
+	const struct xfs_mount	*mp,
+	uint32_t		panic_tag,
+	const char		*fmt, ...)
+{
+	struct va_format	vaf;
+	va_list			args;
+	int			do_panic = 0;
+
+	if (xfs_panic_mask && (xfs_panic_mask & panic_tag)) {
+		xfs_alert(mp, "Transforming an alert into a BUG.");
+		do_panic = 1;
+	}
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	__xfs_printk(KERN_ALERT, mp, &vaf);
+	va_end(args);
+
+	BUG_ON(do_panic);
+}
+
+void
+asswarn(
+	struct xfs_mount	*mp,
+	char			*expr,
+	char			*file,
+	int			line)
+{
+	xfs_warn(mp, "Assertion failed: %s, file: %s, line: %d",
+		expr, file, line);
+	WARN_ON(1);
+}
+
+void
+assfail(
+	struct xfs_mount	*mp,
+	char			*expr,
+	char			*file,
+	int			line)
+{
+	xfs_emerg(mp, "Assertion failed: %s, file: %s, line: %d",
+		expr, file, line);
+	if (xfs_globals.bug_on_assert)
+		BUG();
+	else
+		WARN_ON(1);
+}
+
+void
+xfs_hex_dump(const void *p, int length)
+{
+	print_hex_dump(KERN_ALERT, "", DUMP_PREFIX_OFFSET, 16, 1, p, length, 1);
+}
+
+void
+xfs_buf_alert_ratelimited(
+	struct xfs_buf		*bp,
+	const char		*rlmsg,
+	const char		*fmt,
+	...)
+{
+	struct xfs_mount	*mp = bp->b_mount;
+	struct va_format	vaf;
+	va_list			args;
+
+	/* use the more aggressive per-target rate limit for buffers */
+	if (!___ratelimit(&bp->b_target->bt_ioerror_rl, rlmsg))
+		return;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	__xfs_printk(KERN_ALERT, mp, &vaf);
+	va_end(args);
+}
+
+void
+xfs_warn_experimental(
+	struct xfs_mount		*mp,
+	enum xfs_experimental_feat	feat)
+{
+	static const struct {
+		const char		*name;
+		long			opstate;
+	} features[] = {
+		[XFS_EXPERIMENTAL_SHRINK] = {
+			.opstate	= XFS_OPSTATE_WARNED_SHRINK,
+			.name		= "online shrink",
+		},
+		[XFS_EXPERIMENTAL_LARP] = {
+			.opstate	= XFS_OPSTATE_WARNED_LARP,
+			.name		= "logged extended attributes",
+		},
+	};
+	ASSERT(feat >= 0 && feat < XFS_EXPERIMENTAL_MAX);
+	BUILD_BUG_ON(ARRAY_SIZE(features) != XFS_EXPERIMENTAL_MAX);
+
+	if (xfs_should_warn(mp, features[feat].opstate))
+		xfs_warn(mp,
+ "EXPERIMENTAL %s feature enabled.  Use at your own risk!",
+				features[feat].name);
+}