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, 145 insertions, 0 deletions

diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c
new file mode 100644
index 000000000..563f148be
--- /dev/null
+++ b/fs/jfs/ioctl.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/jfs/ioctl.c
+ *
+ * Copyright (C) 2006 Herbert Poetzl
+ * adapted from Remy Card's ext2/ioctl.c
+ */
+
+#include <linux/fs.h>
+#include <linux/ctype.h>
+#include <linux/capability.h>
+#include <linux/mount.h>
+#include <linux/time.h>
+#include <linux/sched.h>
+#include <linux/blkdev.h>
+#include <asm/current.h>
+#include <linux/uaccess.h>
+#include <linux/fileattr.h>
+
+#include "jfs_filsys.h"
+#include "jfs_debug.h"
+#include "jfs_incore.h"
+#include "jfs_dinode.h"
+#include "jfs_inode.h"
+#include "jfs_dmap.h"
+#include "jfs_discard.h"
+
+static struct {
+	long jfs_flag;
+	long ext2_flag;
+} jfs_map[] = {
+	{JFS_NOATIME_FL,	FS_NOATIME_FL},
+	{JFS_DIRSYNC_FL,	FS_DIRSYNC_FL},
+	{JFS_SYNC_FL,		FS_SYNC_FL},
+	{JFS_SECRM_FL,		FS_SECRM_FL},
+	{JFS_UNRM_FL,		FS_UNRM_FL},
+	{JFS_APPEND_FL,		FS_APPEND_FL},
+	{JFS_IMMUTABLE_FL,	FS_IMMUTABLE_FL},
+	{0, 0},
+};
+
+static long jfs_map_ext2(unsigned long flags, int from)
+{
+	int index=0;
+	long mapped=0;
+
+	while (jfs_map[index].jfs_flag) {
+		if (from) {
+			if (jfs_map[index].ext2_flag & flags)
+				mapped |= jfs_map[index].jfs_flag;
+		} else {
+			if (jfs_map[index].jfs_flag & flags)
+				mapped |= jfs_map[index].ext2_flag;
+		}
+		index++;
+	}
+	return mapped;
+}
+
+int jfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+	struct jfs_inode_info *jfs_inode = JFS_IP(d_inode(dentry));
+	unsigned int flags = jfs_inode->mode2 & JFS_FL_USER_VISIBLE;
+
+	if (d_is_special(dentry))
+		return -ENOTTY;
+
+	fileattr_fill_flags(fa, jfs_map_ext2(flags, 0));
+
+	return 0;
+}
+
+int jfs_fileattr_set(struct mnt_idmap *idmap,
+		     struct dentry *dentry, struct file_kattr *fa)
+{
+	struct inode *inode = d_inode(dentry);
+	struct jfs_inode_info *jfs_inode = JFS_IP(inode);
+	unsigned int flags;
+
+	if (d_is_special(dentry))
+		return -ENOTTY;
+
+	if (fileattr_has_fsx(fa))
+		return -EOPNOTSUPP;
+
+	flags = jfs_map_ext2(fa->flags, 1);
+	if (!S_ISDIR(inode->i_mode))
+		flags &= ~JFS_DIRSYNC_FL;
+
+	/* Is it quota file? Do not allow user to mess with it */
+	if (IS_NOQUOTA(inode))
+		return -EPERM;
+
+	flags = flags & JFS_FL_USER_MODIFIABLE;
+	flags |= jfs_inode->mode2 & ~JFS_FL_USER_MODIFIABLE;
+	jfs_inode->mode2 = flags;
+
+	jfs_set_inode_flags(inode);
+	inode_set_ctime_current(inode);
+	mark_inode_dirty(inode);
+
+	return 0;
+}
+
+long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+
+	switch (cmd) {
+	case FITRIM:
+	{
+		struct super_block *sb = inode->i_sb;
+		struct fstrim_range range;
+		s64 ret = 0;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		if (!bdev_max_discard_sectors(sb->s_bdev)) {
+			jfs_warn("FITRIM not supported on device");
+			return -EOPNOTSUPP;
+		}
+
+		if (copy_from_user(&range, (struct fstrim_range __user *)arg,
+		    sizeof(range)))
+			return -EFAULT;
+
+		range.minlen = max_t(unsigned int, range.minlen,
+				     bdev_discard_granularity(sb->s_bdev));
+
+		ret = jfs_ioc_trim(inode, &range);
+		if (ret < 0)
+			return ret;
+
+		if (copy_to_user((struct fstrim_range __user *)arg, &range,
+		    sizeof(range)))
+			return -EFAULT;
+
+		return 0;
+	}
+
+	default:
+		return -ENOTTY;
+	}
+}