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, 148 insertions, 0 deletions

diff --git a/fs/gfs2/acl.c b/fs/gfs2/acl.c
new file mode 100644
index 000000000..a5b60778b
--- /dev/null
+++ b/fs/gfs2/acl.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/gfs2_ondisk.h>
+
+#include "gfs2.h"
+#include "incore.h"
+#include "acl.h"
+#include "xattr.h"
+#include "glock.h"
+#include "inode.h"
+#include "meta_io.h"
+#include "quota.h"
+#include "rgrp.h"
+#include "trans.h"
+#include "util.h"
+
+static const char *gfs2_acl_name(int type)
+{
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		return XATTR_POSIX_ACL_ACCESS;
+	case ACL_TYPE_DEFAULT:
+		return XATTR_POSIX_ACL_DEFAULT;
+	}
+	return NULL;
+}
+
+static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
+{
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct posix_acl *acl;
+	const char *name;
+	char *data;
+	int len;
+
+	if (!ip->i_eattr)
+		return NULL;
+
+	name = gfs2_acl_name(type);
+	len = gfs2_xattr_acl_get(ip, name, &data);
+	if (len <= 0)
+		return ERR_PTR(len);
+	acl = posix_acl_from_xattr(&init_user_ns, data, len);
+	kfree(data);
+	return acl;
+}
+
+struct posix_acl *gfs2_get_acl(struct inode *inode, int type, bool rcu)
+{
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_holder gh;
+	bool need_unlock = false;
+	struct posix_acl *acl;
+
+	if (rcu)
+		return ERR_PTR(-ECHILD);
+
+	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
+		int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
+					     LM_FLAG_ANY, &gh);
+		if (ret)
+			return ERR_PTR(ret);
+		need_unlock = true;
+	}
+	acl = __gfs2_get_acl(inode, type);
+	if (need_unlock)
+		gfs2_glock_dq_uninit(&gh);
+	return acl;
+}
+
+int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	int error;
+	size_t len = 0;
+	char *data = NULL;
+	const char *name = gfs2_acl_name(type);
+
+	if (acl) {
+		data = posix_acl_to_xattr(&init_user_ns, acl, &len, GFP_NOFS);
+		if (data == NULL)
+			return -ENOMEM;
+	}
+
+	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
+	if (error)
+		goto out;
+	set_cached_acl(inode, type, acl);
+out:
+	kfree(data);
+	return error;
+}
+
+int gfs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		 struct posix_acl *acl, int type)
+{
+	struct inode *inode = d_inode(dentry);
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_holder gh;
+	bool need_unlock = false;
+	int ret;
+	umode_t mode;
+
+	if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
+		return -E2BIG;
+
+	ret = gfs2_qa_get(ip);
+	if (ret)
+		return ret;
+
+	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
+		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
+		if (ret)
+			goto out;
+		need_unlock = true;
+	}
+
+	mode = inode->i_mode;
+	if (type == ACL_TYPE_ACCESS && acl) {
+		ret = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode, &acl);
+		if (ret)
+			goto unlock;
+	}
+
+	ret = __gfs2_set_acl(inode, acl, type);
+	if (!ret && mode != inode->i_mode) {
+		inode_set_ctime_current(inode);
+		inode->i_mode = mode;
+		mark_inode_dirty(inode);
+	}
+unlock:
+	if (need_unlock)
+		gfs2_glock_dq_uninit(&gh);
+out:
+	gfs2_qa_put(ip);
+	return ret;
+}