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, 208 insertions, 0 deletions

diff --git a/fs/coda/coda_linux.c b/fs/coda/coda_linux.c
new file mode 100644
index 000000000..1d2dac95f
--- /dev/null
+++ b/fs/coda/coda_linux.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Inode operations for Coda filesystem
+ * Original version: (C) 1996 P. Braam and M. Callahan
+ * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
+ * 
+ * Carnegie Mellon encourages users to contribute improvements to
+ * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/uaccess.h>
+#include <linux/string.h>
+
+#include <linux/coda.h>
+#include "coda_psdev.h"
+#include "coda_linux.h"
+
+/* initialize the debugging variables */
+int coda_fake_statfs;
+
+/* print a fid */
+char * coda_f2s(struct CodaFid *f)
+{
+	static char s[60];
+
+ 	sprintf(s, "(%08x.%08x.%08x.%08x)", f->opaque[0], f->opaque[1], f->opaque[2], f->opaque[3]);
+
+	return s;
+}
+
+/* recognize special .CONTROL name */
+int coda_iscontrol(const char *name, size_t length)
+{
+	return ((CODA_CONTROLLEN == length) && 
+                (strncmp(name, CODA_CONTROL, CODA_CONTROLLEN) == 0));
+}
+
+unsigned short coda_flags_to_cflags(unsigned short flags)
+{
+	unsigned short coda_flags = 0;
+	
+	if ((flags & O_ACCMODE) == O_RDONLY)
+		coda_flags |= C_O_READ;
+
+	if ((flags & O_ACCMODE) == O_RDWR)
+		coda_flags |= C_O_READ | C_O_WRITE;
+
+	if ((flags & O_ACCMODE) == O_WRONLY)
+		coda_flags |= C_O_WRITE;
+
+	if (flags & O_TRUNC)
+		coda_flags |= C_O_TRUNC;
+
+	if (flags & O_CREAT)
+		coda_flags |= C_O_CREAT;
+
+	if (flags & O_EXCL)
+		coda_flags |= C_O_EXCL;
+
+	return coda_flags;
+}
+
+static struct timespec64 coda_to_timespec64(struct coda_timespec ts)
+{
+	struct timespec64 ts64 = {
+		.tv_sec = ts.tv_sec,
+		.tv_nsec = ts.tv_nsec,
+	};
+
+	return ts64;
+}
+
+static struct coda_timespec timespec64_to_coda(struct timespec64 ts64)
+{
+	struct coda_timespec ts = {
+		.tv_sec = ts64.tv_sec,
+		.tv_nsec = ts64.tv_nsec,
+	};
+
+	return ts;
+}
+
+/* utility functions below */
+umode_t coda_inode_type(struct coda_vattr *attr)
+{
+	switch (attr->va_type) {
+	case C_VREG:
+		return S_IFREG;
+	case C_VDIR:
+		return S_IFDIR;
+	case C_VLNK:
+		return S_IFLNK;
+	case C_VNON:
+	default:
+		return 0;
+	}
+}
+
+void coda_vattr_to_iattr(struct inode *inode, struct coda_vattr *attr)
+{
+	/* inode's i_flags, i_ino are set by iget
+	 * XXX: is this all we need ??
+	 */
+	umode_t inode_type = coda_inode_type(attr);
+	inode->i_mode |= inode_type;
+
+	if (attr->va_mode != (u_short) -1)
+	        inode->i_mode = attr->va_mode | inode_type;
+        if (attr->va_uid != -1) 
+	        inode->i_uid = make_kuid(&init_user_ns, (uid_t) attr->va_uid);
+        if (attr->va_gid != -1)
+	        inode->i_gid = make_kgid(&init_user_ns, (gid_t) attr->va_gid);
+	if (attr->va_nlink != -1)
+		set_nlink(inode, attr->va_nlink);
+	if (attr->va_size != -1)
+	        inode->i_size = attr->va_size;
+	if (attr->va_size != -1)
+		inode->i_blocks = (attr->va_size + 511) >> 9;
+	if (attr->va_atime.tv_sec != -1) 
+		inode_set_atime_to_ts(inode,
+				      coda_to_timespec64(attr->va_atime));
+	if (attr->va_mtime.tv_sec != -1)
+		inode_set_mtime_to_ts(inode,
+				      coda_to_timespec64(attr->va_mtime));
+        if (attr->va_ctime.tv_sec != -1)
+		inode_set_ctime_to_ts(inode,
+				      coda_to_timespec64(attr->va_ctime));
+}
+
+
+/* 
+ * BSD sets attributes that need not be modified to -1. 
+ * Linux uses the valid field to indicate what should be
+ * looked at.  The BSD type field needs to be deduced from linux 
+ * mode.
+ * So we have to do some translations here.
+ */
+
+void coda_iattr_to_vattr(struct iattr *iattr, struct coda_vattr *vattr)
+{
+        unsigned int valid;
+
+        /* clean out */        
+	vattr->va_mode = -1;
+        vattr->va_uid = (vuid_t) -1; 
+        vattr->va_gid = (vgid_t) -1;
+        vattr->va_size = (off_t) -1;
+	vattr->va_atime.tv_sec = (int64_t) -1;
+	vattr->va_atime.tv_nsec = (long) -1;
+	vattr->va_mtime.tv_sec = (int64_t) -1;
+	vattr->va_mtime.tv_nsec = (long) -1;
+	vattr->va_ctime.tv_sec = (int64_t) -1;
+	vattr->va_ctime.tv_nsec = (long) -1;
+        vattr->va_type = C_VNON;
+	vattr->va_fileid = -1;
+	vattr->va_gen = -1;
+	vattr->va_bytes = -1;
+	vattr->va_nlink = -1;
+	vattr->va_blocksize = -1;
+	vattr->va_rdev = -1;
+        vattr->va_flags = 0;
+
+        /* determine the type */
+#if 0
+        mode = iattr->ia_mode;
+                if ( S_ISDIR(mode) ) {
+                vattr->va_type = C_VDIR; 
+        } else if ( S_ISREG(mode) ) {
+                vattr->va_type = C_VREG;
+        } else if ( S_ISLNK(mode) ) {
+                vattr->va_type = C_VLNK;
+        } else {
+                /* don't do others */
+                vattr->va_type = C_VNON;
+        }
+#endif 
+
+        /* set those vattrs that need change */
+        valid = iattr->ia_valid;
+        if ( valid & ATTR_MODE ) {
+                vattr->va_mode = iattr->ia_mode;
+	}
+        if ( valid & ATTR_UID ) {
+                vattr->va_uid = (vuid_t) from_kuid(&init_user_ns, iattr->ia_uid);
+	}
+        if ( valid & ATTR_GID ) {
+                vattr->va_gid = (vgid_t) from_kgid(&init_user_ns, iattr->ia_gid);
+	}
+        if ( valid & ATTR_SIZE ) {
+                vattr->va_size = iattr->ia_size;
+	}
+        if ( valid & ATTR_ATIME ) {
+		vattr->va_atime = timespec64_to_coda(iattr->ia_atime);
+	}
+        if ( valid & ATTR_MTIME ) {
+		vattr->va_mtime = timespec64_to_coda(iattr->ia_mtime);
+	}
+        if ( valid & ATTR_CTIME ) {
+		vattr->va_ctime = timespec64_to_coda(iattr->ia_ctime);
+	}
+}
+