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/smb/client/reparse.h b/fs/smb/client/reparse.h
new file mode 100644
index 000000000..49efd85b1
--- /dev/null
+++ b/fs/smb/client/reparse.h
@@ -0,0 +1,145 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024 Paulo Alcantara <pc@manguebit.com>
+ */
+
+#ifndef _CIFS_REPARSE_H
+#define _CIFS_REPARSE_H
+
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/uidgid.h>
+#include "fs_context.h"
+#include "cifsglob.h"
+#include "../common/smbfsctl.h"
+
+#define REPARSE_SYM_PATH_MAX 4060
+
+/*
+ * Used only by cifs.ko to ignore reparse points from files when client or
+ * server doesn't support FSCTL_GET_REPARSE_POINT.
+ */
+#define IO_REPARSE_TAG_INTERNAL ((__u32)~0U)
+
+static inline dev_t reparse_mkdev(void *ptr)
+{
+	u64 v = le64_to_cpu(*(__le64 *)ptr);
+
+	return MKDEV(v & 0xffffffff, v >> 32);
+}
+
+static inline kuid_t wsl_make_kuid(struct cifs_sb_info *cifs_sb,
+				   void *ptr)
+{
+	u32 uid = le32_to_cpu(*(__le32 *)ptr);
+
+	if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_OVERR_UID)
+		return cifs_sb->ctx->linux_uid;
+	return make_kuid(current_user_ns(), uid);
+}
+
+static inline kgid_t wsl_make_kgid(struct cifs_sb_info *cifs_sb,
+				   void *ptr)
+{
+	u32 gid = le32_to_cpu(*(__le32 *)ptr);
+
+	if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_OVERR_GID)
+		return cifs_sb->ctx->linux_gid;
+	return make_kgid(current_user_ns(), gid);
+}
+
+static inline u64 reparse_mode_nfs_type(mode_t mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFLNK: return NFS_SPECFILE_LNK;
+	case S_IFBLK: return NFS_SPECFILE_BLK;
+	case S_IFCHR: return NFS_SPECFILE_CHR;
+	case S_IFIFO: return NFS_SPECFILE_FIFO;
+	case S_IFSOCK: return NFS_SPECFILE_SOCK;
+	}
+	return 0;
+}
+
+static inline u32 reparse_mode_wsl_tag(mode_t mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFLNK: return IO_REPARSE_TAG_LX_SYMLINK;
+	case S_IFBLK: return IO_REPARSE_TAG_LX_BLK;
+	case S_IFCHR: return IO_REPARSE_TAG_LX_CHR;
+	case S_IFIFO: return IO_REPARSE_TAG_LX_FIFO;
+	case S_IFSOCK: return IO_REPARSE_TAG_AF_UNIX;
+	}
+	return 0;
+}
+
+/*
+ * Match a reparse point inode if reparse tag and ctime haven't changed.
+ *
+ * Windows Server updates ctime of reparse points when their data have changed.
+ * The server doesn't allow changing reparse tags from existing reparse points,
+ * though it's worth checking.
+ */
+static inline bool reparse_inode_match(struct inode *inode,
+				       struct cifs_fattr *fattr)
+{
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct timespec64 ctime = inode_get_ctime(inode);
+
+	/*
+	 * Do not match reparse tags when client or server doesn't support
+	 * FSCTL_GET_REPARSE_POINT.  @fattr->cf_cifstag should contain correct
+	 * reparse tag from query dir response but the client won't be able to
+	 * read the reparse point data anyway.  This spares us a revalidation.
+	 */
+	if (cinode->reparse_tag != IO_REPARSE_TAG_INTERNAL &&
+	    cinode->reparse_tag != fattr->cf_cifstag)
+		return false;
+	return (cinode->cifsAttrs & ATTR_REPARSE_POINT) &&
+		timespec64_equal(&ctime, &fattr->cf_ctime);
+}
+
+static inline u32 cifs_open_data_attrs(const struct cifs_open_info_data *data)
+{
+	if (data->contains_posix_file_info)
+		return le32_to_cpu(data->posix_fi.DosAttributes);
+
+	return le32_to_cpu(data->fi.Attributes);
+}
+
+static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
+{
+	u32 attrs = cifs_open_data_attrs(data);
+
+	if (data->contains_posix_file_info) {
+		struct smb311_posix_qinfo *fi = &data->posix_fi;
+
+		if (data->reparse_point) {
+			attrs |= ATTR_REPARSE_POINT;
+			fi->DosAttributes = cpu_to_le32(attrs);
+		}
+
+	} else {
+		struct smb2_file_all_info *fi = &data->fi;
+
+		if (data->reparse_point) {
+			attrs |= ATTR_REPARSE_POINT;
+			fi->Attributes = cpu_to_le32(attrs);
+		}
+	}
+
+	return attrs & ATTR_REPARSE_POINT;
+}
+
+bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
+				 struct cifs_fattr *fattr,
+				 struct cifs_open_info_data *data);
+int create_reparse_symlink(const unsigned int xid, struct inode *inode,
+			   struct dentry *dentry, struct cifs_tcon *tcon,
+			   const char *full_path, const char *symname);
+int mknod_reparse(unsigned int xid, struct inode *inode, struct dentry *dentry,
+		  struct cifs_tcon *tcon, const char *full_path, umode_t mode,
+		  dev_t dev);
+struct reparse_data_buffer *smb2_get_reparse_point_buffer(const struct kvec *rsp_iov,
+							  u32 *plen);
+
+#endif /* _CIFS_REPARSE_H */