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, 180 insertions, 0 deletions

diff --git a/fs/minix/minix.h b/fs/minix/minix.h
new file mode 100644
index 000000000..78722ce22
--- /dev/null
+++ b/fs/minix/minix.h
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef FS_MINIX_H
+#define FS_MINIX_H
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/minix_fs.h>
+
+#define INODE_VERSION(inode)	minix_sb(inode->i_sb)->s_version
+#define MINIX_V1		0x0001		/* original minix fs */
+#define MINIX_V2		0x0002		/* minix V2 fs */
+#define MINIX_V3		0x0003		/* minix V3 fs */
+
+/*
+ * minix fs inode data in memory
+ */
+struct minix_inode_info {
+	union {
+		__u16 i1_data[16];
+		__u32 i2_data[16];
+	} u;
+	struct mapping_metadata_bhs i_metadata_bhs;
+	struct inode vfs_inode;
+};
+
+/*
+ * minix super-block data in memory
+ */
+struct minix_sb_info {
+	unsigned long s_ninodes;
+	unsigned long s_nzones;
+	unsigned long s_imap_blocks;
+	unsigned long s_zmap_blocks;
+	unsigned long s_firstdatazone;
+	unsigned long s_log_zone_size;
+	int s_dirsize;
+	int s_namelen;
+	struct buffer_head ** s_imap;
+	struct buffer_head ** s_zmap;
+	struct buffer_head * s_sbh;
+	struct minix_super_block * s_ms;
+	unsigned short s_mount_state;
+	unsigned short s_version;
+};
+
+void __minix_error_inode(struct inode *inode, const char *function,
+			 unsigned int line, const char *fmt, ...);
+
+struct inode *minix_iget(struct super_block *, unsigned long);
+struct minix_inode *minix_V1_raw_inode(struct super_block *, ino_t, struct buffer_head **);
+struct minix2_inode *minix_V2_raw_inode(struct super_block *, ino_t, struct buffer_head **);
+struct inode *minix_new_inode(const struct inode *, umode_t);
+void minix_free_inode(struct inode *inode);
+unsigned long minix_count_free_inodes(struct super_block *sb);
+int minix_new_block(struct inode *inode);
+void minix_free_block(struct inode *inode, unsigned long block);
+unsigned long minix_count_free_blocks(struct super_block *sb);
+int minix_getattr(struct mnt_idmap *, const struct path *,
+		struct kstat *, u32, unsigned int);
+int minix_prepare_chunk(struct folio *folio, loff_t pos, unsigned len);
+struct mapping_metadata_bhs *minix_get_metadata_bhs(struct inode *inode);
+
+extern void V1_minix_truncate(struct inode *);
+extern void V2_minix_truncate(struct inode *);
+extern void minix_truncate(struct inode *);
+extern void minix_set_inode(struct inode *, dev_t);
+extern int V1_minix_get_block(struct inode *, long, struct buffer_head *, int);
+extern int V2_minix_get_block(struct inode *, long, struct buffer_head *, int);
+extern unsigned V1_minix_blocks(loff_t, struct super_block *);
+extern unsigned V2_minix_blocks(loff_t, struct super_block *);
+
+struct minix_dir_entry *minix_find_entry(struct dentry *, struct folio **);
+int minix_add_link(struct dentry*, struct inode*);
+int minix_delete_entry(struct minix_dir_entry *, struct folio *);
+int minix_make_empty(struct inode*, struct inode*);
+int minix_empty_dir(struct inode*);
+int minix_set_link(struct minix_dir_entry *de, struct folio *folio,
+		struct inode *inode);
+struct minix_dir_entry *minix_dotdot(struct inode*, struct folio **);
+ino_t minix_inode_by_name(struct dentry*);
+
+extern const struct inode_operations minix_file_inode_operations;
+extern const struct inode_operations minix_dir_inode_operations;
+extern const struct file_operations minix_file_operations;
+extern const struct file_operations minix_dir_operations;
+
+static inline struct minix_sb_info *minix_sb(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct minix_inode_info *minix_i(struct inode *inode)
+{
+	return container_of(inode, struct minix_inode_info, vfs_inode);
+}
+
+static inline unsigned minix_blocks_needed(unsigned bits, unsigned blocksize)
+{
+	return DIV_ROUND_UP_POW2(bits, blocksize * 8);
+}
+
+#if defined(CONFIG_MINIX_FS_NATIVE_ENDIAN) && \
+	defined(CONFIG_MINIX_FS_BIG_ENDIAN_16BIT_INDEXED)
+
+#error Minix file system byte order broken
+
+#elif defined(CONFIG_MINIX_FS_NATIVE_ENDIAN)
+
+/*
+ * big-endian 32 or 64 bit indexed bitmaps on big-endian system or
+ * little-endian bitmaps on little-endian system
+ */
+
+#define minix_test_and_set_bit(nr, addr)	\
+	__test_and_set_bit((nr), (unsigned long *)(addr))
+#define minix_set_bit(nr, addr)		\
+	__set_bit((nr), (unsigned long *)(addr))
+#define minix_test_and_clear_bit(nr, addr) \
+	__test_and_clear_bit((nr), (unsigned long *)(addr))
+#define minix_test_bit(nr, addr)		\
+	test_bit((nr), (unsigned long *)(addr))
+#define minix_find_first_zero_bit(addr, size) \
+	find_first_zero_bit((unsigned long *)(addr), (size))
+
+#elif defined(CONFIG_MINIX_FS_BIG_ENDIAN_16BIT_INDEXED)
+
+/*
+ * big-endian 16bit indexed bitmaps
+ */
+
+static inline int minix_find_first_zero_bit(const void *vaddr, unsigned size)
+{
+	const unsigned short *p = vaddr, *addr = vaddr;
+	unsigned short num;
+
+	if (!size)
+		return 0;
+
+	size >>= 4;
+	while (*p++ == 0xffff) {
+		if (--size == 0)
+			return (p - addr) << 4;
+	}
+
+	num = *--p;
+	return ((p - addr) << 4) + ffz(num);
+}
+
+#define minix_test_and_set_bit(nr, addr)	\
+	__test_and_set_bit((nr) ^ 16, (unsigned long *)(addr))
+#define minix_set_bit(nr, addr)	\
+	__set_bit((nr) ^ 16, (unsigned long *)(addr))
+#define minix_test_and_clear_bit(nr, addr)	\
+	__test_and_clear_bit((nr) ^ 16, (unsigned long *)(addr))
+
+static inline int minix_test_bit(int nr, const void *vaddr)
+{
+	const unsigned short *p = vaddr;
+	return (p[nr >> 4] & (1U << (nr & 15))) != 0;
+}
+
+#else
+
+/*
+ * little-endian bitmaps
+ */
+
+#define minix_test_and_set_bit	__test_and_set_bit_le
+#define minix_set_bit		__set_bit_le
+#define minix_test_and_clear_bit	__test_and_clear_bit_le
+#define minix_test_bit	test_bit_le
+#define minix_find_first_zero_bit	find_first_zero_bit_le
+
+#endif
+
+#define minix_error_inode(inode, fmt, ...)			\
+	__minix_error_inode((inode), __func__, __LINE__,	\
+			    (fmt), ##__VA_ARGS__)
+
+#endif /* FS_MINIX_H */