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, 169 insertions, 0 deletions

diff --git a/fs/hfsplus/options.c b/fs/hfsplus/options.c
new file mode 100644
index 000000000..9b377481f
--- /dev/null
+++ b/fs/hfsplus/options.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hfsplus/options.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Option parsing
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/fs_struct.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/nls.h>
+#include <linux/mount.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include "hfsplus_fs.h"
+
+enum {
+	opt_creator, opt_type,
+	opt_umask, opt_uid, opt_gid,
+	opt_part, opt_session, opt_nls,
+	opt_decompose, opt_barrier,
+	opt_force,
+};
+
+static const struct fs_parameter_spec hfs_param_spec[] = {
+	fsparam_string	("creator",	opt_creator),
+	fsparam_string	("type",	opt_type),
+	fsparam_u32oct	("umask",	opt_umask),
+	fsparam_u32	("uid",		opt_uid),
+	fsparam_u32	("gid",		opt_gid),
+	fsparam_u32	("part",	opt_part),
+	fsparam_u32	("session",	opt_session),
+	fsparam_string	("nls",		opt_nls),
+	fsparam_flag_no	("decompose",	opt_decompose),
+	fsparam_flag_no	("barrier",	opt_barrier),
+	fsparam_flag	("force",	opt_force),
+	{}
+};
+
+/* Initialize an options object to reasonable defaults */
+void hfsplus_fill_defaults(struct hfsplus_sb_info *opts)
+{
+	if (!opts)
+		return;
+
+	opts->creator = HFSPLUS_DEF_CR_TYPE;
+	opts->type = HFSPLUS_DEF_CR_TYPE;
+	opts->umask = current_umask();
+	opts->uid = current_uid();
+	opts->gid = current_gid();
+	opts->part = -1;
+	opts->session = -1;
+}
+
+/* Parse options from mount. Returns nonzero errno on failure */
+int hfsplus_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct hfsplus_sb_info *sbi = fc->s_fs_info;
+	struct fs_parse_result result;
+	int opt;
+
+	/*
+	 * Only the force option is examined during remount, all others
+	 * are ignored.
+	 */
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE &&
+	    strncmp(param->key, "force", 5))
+		return 0;
+
+	opt = fs_parse(fc, hfs_param_spec, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case opt_creator:
+		if (strlen(param->string) != 4) {
+			pr_err("creator requires a 4 character value\n");
+			return -EINVAL;
+		}
+		memcpy(&sbi->creator, param->string, 4);
+		break;
+	case opt_type:
+		if (strlen(param->string) != 4) {
+			pr_err("type requires a 4 character value\n");
+			return -EINVAL;
+		}
+		memcpy(&sbi->type, param->string, 4);
+		break;
+	case opt_umask:
+		sbi->umask = (umode_t)result.uint_32;
+		break;
+	case opt_uid:
+		sbi->uid = result.uid;
+		set_bit(HFSPLUS_SB_UID, &sbi->flags);
+		break;
+	case opt_gid:
+		sbi->gid = result.gid;
+		set_bit(HFSPLUS_SB_GID, &sbi->flags);
+		break;
+	case opt_part:
+		sbi->part = result.uint_32;
+		break;
+	case opt_session:
+		sbi->session = result.uint_32;
+		break;
+	case opt_nls:
+		if (sbi->nls) {
+			pr_err("unable to change nls mapping\n");
+			return -EINVAL;
+		}
+		sbi->nls = load_nls(param->string);
+		if (!sbi->nls) {
+			pr_err("unable to load nls mapping \"%s\"\n",
+			       param->string);
+			return -EINVAL;
+		}
+		break;
+	case opt_decompose:
+		if (result.negated)
+			set_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
+		else
+			clear_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
+		break;
+	case opt_barrier:
+		if (result.negated)
+			set_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
+		else
+			clear_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
+		break;
+	case opt_force:
+		set_bit(HFSPLUS_SB_FORCE, &sbi->flags);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int hfsplus_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(root->d_sb);
+
+	if (sbi->creator != HFSPLUS_DEF_CR_TYPE)
+		seq_show_option_n(seq, "creator", (char *)&sbi->creator, 4);
+	if (sbi->type != HFSPLUS_DEF_CR_TYPE)
+		seq_show_option_n(seq, "type", (char *)&sbi->type, 4);
+	seq_printf(seq, ",umask=%o,uid=%u,gid=%u", sbi->umask,
+			from_kuid_munged(&init_user_ns, sbi->uid),
+			from_kgid_munged(&init_user_ns, sbi->gid));
+	if (sbi->part >= 0)
+		seq_printf(seq, ",part=%u", sbi->part);
+	if (sbi->session >= 0)
+		seq_printf(seq, ",session=%u", sbi->session);
+	if (sbi->nls)
+		seq_printf(seq, ",nls=%s", sbi->nls->charset);
+	if (test_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags))
+		seq_puts(seq, ",nodecompose");
+	if (test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
+		seq_puts(seq, ",nobarrier");
+	return 0;
+}