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, 100 insertions, 0 deletions

diff --git a/fs/ntfs/bitmap.h b/fs/ntfs/bitmap.h
new file mode 100644
index 000000000..31177fe61
--- /dev/null
+++ b/fs/ntfs/bitmap.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for NTFS kernel bitmap handling.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ */
+
+#ifndef _LINUX_NTFS_BITMAP_H
+#define _LINUX_NTFS_BITMAP_H
+
+#include <linux/fs.h>
+
+#include "volume.h"
+
+int ntfs_trim_fs(struct ntfs_volume *vol, struct fstrim_range *range);
+int __ntfs_bitmap_set_bits_in_run(struct inode *vi, const s64 start_bit,
+		const s64 count, const u8 value, const bool is_rollback);
+
+/*
+ * ntfs_bitmap_set_bits_in_run - set a run of bits in a bitmap to a value
+ * @vi:			vfs inode describing the bitmap
+ * @start_bit:		first bit to set
+ * @count:		number of bits to set
+ * @value:		value to set the bits to (i.e. 0 or 1)
+ *
+ * Set @count bits starting at bit @start_bit in the bitmap described by the
+ * vfs inode @vi to @value, where @value is either 0 or 1.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_set_bits_in_run(struct inode *vi,
+		const s64 start_bit, const s64 count, const u8 value)
+{
+	return __ntfs_bitmap_set_bits_in_run(vi, start_bit, count, value,
+			false);
+}
+
+/*
+ * ntfs_bitmap_set_run - set a run of bits in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @start_bit:	first bit to set
+ * @count:	number of bits to set
+ *
+ * Set @count bits starting at bit @start_bit in the bitmap described by the
+ * vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_set_run(struct inode *vi, const s64 start_bit,
+		const s64 count)
+{
+	return ntfs_bitmap_set_bits_in_run(vi, start_bit, count, 1);
+}
+
+/*
+ * ntfs_bitmap_clear_run - clear a run of bits in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @start_bit:	first bit to clear
+ * @count:	number of bits to clear
+ *
+ * Clear @count bits starting at bit @start_bit in the bitmap described by the
+ * vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_clear_run(struct inode *vi, const s64 start_bit,
+		const s64 count)
+{
+	return ntfs_bitmap_set_bits_in_run(vi, start_bit, count, 0);
+}
+
+/*
+ * ntfs_bitmap_set_bit - set a bit in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @bit:	bit to set
+ *
+ * Set bit @bit in the bitmap described by the vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_set_bit(struct inode *vi, const s64 bit)
+{
+	return ntfs_bitmap_set_run(vi, bit, 1);
+}
+
+/*
+ * ntfs_bitmap_clear_bit - clear a bit in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @bit:	bit to clear
+ *
+ * Clear bit @bit in the bitmap described by the vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_clear_bit(struct inode *vi, const s64 bit)
+{
+	return ntfs_bitmap_clear_run(vi, bit, 1);
+}
+
+#endif /* defined _LINUX_NTFS_BITMAP_H */