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, 146 insertions, 0 deletions

diff --git a/fs/ntfs/collate.c b/fs/ntfs/collate.c
new file mode 100644
index 000000000..77e340389
--- /dev/null
+++ b/fs/ntfs/collate.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * NTFS kernel collation handling.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ *
+ * Part of this file is based on code from the NTFS-3G.
+ * and is copyrighted by the respective authors below:
+ * Copyright (c) 2004 Anton Altaparmakov
+ * Copyright (c) 2005 Yura Pakhuchiy
+ */
+
+#include "collate.h"
+#include "debug.h"
+#include "ntfs.h"
+
+#include <linux/sort.h>
+
+static int ntfs_collate_binary(struct ntfs_volume *vol,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len)
+{
+	int rc;
+
+	rc = memcmp(data1, data2, min(data1_len, data2_len));
+	if (!rc && (data1_len != data2_len)) {
+		if (data1_len < data2_len)
+			rc = -1;
+		else
+			rc = 1;
+	}
+	return rc;
+}
+
+static int ntfs_collate_ntofs_ulong(struct ntfs_volume *vol,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len)
+{
+	int rc;
+	u32 d1 = le32_to_cpup(data1), d2 = le32_to_cpup(data2);
+
+	if (data1_len != data2_len || data1_len != 4)
+		return -EINVAL;
+
+	if (d1 < d2)
+		rc = -1;
+	else {
+		if (d1 == d2)
+			rc = 0;
+		else
+			rc = 1;
+	}
+	return rc;
+}
+
+/*
+ * ntfs_collate_ntofs_ulongs - Which of two le32 arrays should be listed first
+ * @vol: ntfs volume
+ * @data1: first ulong array to collate
+ * @data1_len: length in bytes of @data1
+ * @data2: second ulong array to collate
+ * @data2_len: length in bytes of @data2
+ *
+ * Returns: -1, 0 or 1 depending of how the arrays compare
+ */
+static int ntfs_collate_ntofs_ulongs(struct ntfs_volume *vol,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len)
+{
+	int len;
+	const __le32 *p1 = data1, *p2 = data2;
+	u32 d1, d2;
+
+	if (data1_len != data2_len || data1_len & 3) {
+		ntfs_error(vol->sb, "data1_len or data2_len not valid\n");
+		return -1;
+	}
+
+	len = data1_len;
+	do {
+		d1 = le32_to_cpup(p1);
+		p1++;
+		d2 = le32_to_cpup(p2);
+		p2++;
+	} while (d1 == d2 && (len -= 4) > 0);
+	return cmp_int(d1, d2);
+}
+
+/*
+ * ntfs_collate_file_name - Which of two filenames should be listed first
+ * @vol: ntfs volume
+ * @data1: first filename to collate
+ * @data1_len: length in bytes of @data1(unused)
+ * @data2: second filename to collate
+ * @data2_len: length in bytes of @data2(unused)
+ */
+static int ntfs_collate_file_name(struct ntfs_volume *vol,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len)
+{
+	int rc;
+
+	rc = ntfs_file_compare_values(data1, data2, -EINVAL,
+			IGNORE_CASE, vol->upcase, vol->upcase_len);
+	if (!rc)
+		rc = ntfs_file_compare_values(data1, data2,
+			-EINVAL, CASE_SENSITIVE, vol->upcase, vol->upcase_len);
+	return rc;
+}
+
+/*
+ * ntfs_collate - collate two data items using a specified collation rule
+ * @vol:	ntfs volume to which the data items belong
+ * @cr:		collation rule to use when comparing the items
+ * @data1:	first data item to collate
+ * @data1_len:	length in bytes of @data1
+ * @data2:	second data item to collate
+ * @data2_len:	length in bytes of @data2
+ *
+ * Collate the two data items @data1 and @data2 using the collation rule @cr
+ * and return -1, 0, ir 1 if @data1 is found, respectively, to collate before,
+ * to match, or to collate after @data2. return -EINVAL if an error occurred.
+ */
+int ntfs_collate(struct ntfs_volume *vol, __le32 cr,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len)
+{
+	switch (le32_to_cpu(cr)) {
+	case le32_to_cpu(COLLATION_BINARY):
+		return ntfs_collate_binary(vol, data1, data1_len,
+					   data2, data2_len);
+	case le32_to_cpu(COLLATION_FILE_NAME):
+		return ntfs_collate_file_name(vol, data1, data1_len,
+					      data2, data2_len);
+	case le32_to_cpu(COLLATION_NTOFS_ULONG):
+		return ntfs_collate_ntofs_ulong(vol, data1, data1_len,
+						data2, data2_len);
+	case le32_to_cpu(COLLATION_NTOFS_ULONGS):
+		return ntfs_collate_ntofs_ulongs(vol, data1, data1_len,
+						 data2, data2_len);
+	default:
+		ntfs_error(vol->sb, "Unknown collation rule 0x%x",
+			   le32_to_cpu(cr));
+		return -EINVAL;
+	}
+}