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/block/blk-crypto-sysfs.c b/block/blk-crypto-sysfs.c
new file mode 100644
index 000000000..b069c418b
--- /dev/null
+++ b/block/blk-crypto-sysfs.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2021 Google LLC
+ *
+ * sysfs support for blk-crypto.  This file contains the code which exports the
+ * crypto capabilities of devices via /sys/block/$disk/queue/crypto/.
+ */
+
+#include <linux/blk-crypto-profile.h>
+
+#include "blk-crypto-internal.h"
+
+struct blk_crypto_kobj {
+	struct kobject kobj;
+	struct blk_crypto_profile *profile;
+};
+
+struct blk_crypto_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct blk_crypto_profile *profile,
+			const struct blk_crypto_attr *attr, char *page);
+};
+
+static struct blk_crypto_profile *kobj_to_crypto_profile(struct kobject *kobj)
+{
+	return container_of(kobj, struct blk_crypto_kobj, kobj)->profile;
+}
+
+static const struct blk_crypto_attr *attr_to_crypto_attr(const struct attribute *attr)
+{
+	return container_of_const(attr, struct blk_crypto_attr, attr);
+}
+
+static ssize_t hw_wrapped_keys_show(struct blk_crypto_profile *profile,
+				    const struct blk_crypto_attr *attr, char *page)
+{
+	/* Always show supported, since the file doesn't exist otherwise. */
+	return sysfs_emit(page, "supported\n");
+}
+
+static ssize_t max_dun_bits_show(struct blk_crypto_profile *profile,
+				 const struct blk_crypto_attr *attr, char *page)
+{
+	return sysfs_emit(page, "%u\n", 8 * profile->max_dun_bytes_supported);
+}
+
+static ssize_t num_keyslots_show(struct blk_crypto_profile *profile,
+				 const struct blk_crypto_attr *attr, char *page)
+{
+	return sysfs_emit(page, "%u\n", profile->num_slots);
+}
+
+static ssize_t raw_keys_show(struct blk_crypto_profile *profile,
+			     const struct blk_crypto_attr *attr, char *page)
+{
+	/* Always show supported, since the file doesn't exist otherwise. */
+	return sysfs_emit(page, "supported\n");
+}
+
+#define BLK_CRYPTO_RO_ATTR(_name) \
+	static const struct blk_crypto_attr _name##_attr = __ATTR_RO(_name)
+
+BLK_CRYPTO_RO_ATTR(hw_wrapped_keys);
+BLK_CRYPTO_RO_ATTR(max_dun_bits);
+BLK_CRYPTO_RO_ATTR(num_keyslots);
+BLK_CRYPTO_RO_ATTR(raw_keys);
+
+static umode_t blk_crypto_is_visible(struct kobject *kobj,
+				     const struct attribute *attr, int n)
+{
+	struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);
+	const struct blk_crypto_attr *a = attr_to_crypto_attr(attr);
+
+	if (a == &hw_wrapped_keys_attr &&
+	    !(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED))
+		return 0;
+	if (a == &raw_keys_attr &&
+	    !(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_RAW))
+		return 0;
+
+	return 0444;
+}
+
+static const struct attribute *const blk_crypto_attrs[] = {
+	&hw_wrapped_keys_attr.attr,
+	&max_dun_bits_attr.attr,
+	&num_keyslots_attr.attr,
+	&raw_keys_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group blk_crypto_attr_group = {
+	.attrs_const = blk_crypto_attrs,
+	.is_visible_const = blk_crypto_is_visible,
+};
+
+/*
+ * The encryption mode attributes.  To avoid hard-coding the list of encryption
+ * modes, these are initialized at boot time by blk_crypto_sysfs_init().
+ */
+static struct blk_crypto_attr __blk_crypto_mode_attrs[BLK_ENCRYPTION_MODE_MAX];
+static const struct attribute *blk_crypto_mode_attrs[BLK_ENCRYPTION_MODE_MAX + 1];
+
+static umode_t blk_crypto_mode_is_visible(struct kobject *kobj,
+					  const struct attribute *attr, int n)
+{
+	struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);
+	const struct blk_crypto_attr *a = attr_to_crypto_attr(attr);
+	int mode_num = a - __blk_crypto_mode_attrs;
+
+	if (profile->modes_supported[mode_num])
+		return 0444;
+	return 0;
+}
+
+static ssize_t blk_crypto_mode_show(struct blk_crypto_profile *profile,
+				    const struct blk_crypto_attr *attr, char *page)
+{
+	int mode_num = attr - __blk_crypto_mode_attrs;
+
+	return sysfs_emit(page, "0x%x\n", profile->modes_supported[mode_num]);
+}
+
+static const struct attribute_group blk_crypto_modes_attr_group = {
+	.name = "modes",
+	.attrs_const = blk_crypto_mode_attrs,
+	.is_visible_const = blk_crypto_mode_is_visible,
+};
+
+static const struct attribute_group *blk_crypto_attr_groups[] = {
+	&blk_crypto_attr_group,
+	&blk_crypto_modes_attr_group,
+	NULL,
+};
+
+static ssize_t blk_crypto_attr_show(struct kobject *kobj,
+				    struct attribute *attr, char *page)
+{
+	struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);
+	const struct blk_crypto_attr *a = attr_to_crypto_attr(attr);
+
+	return a->show(profile, a, page);
+}
+
+static const struct sysfs_ops blk_crypto_attr_ops = {
+	.show = blk_crypto_attr_show,
+};
+
+static void blk_crypto_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct blk_crypto_kobj, kobj));
+}
+
+static const struct kobj_type blk_crypto_ktype = {
+	.default_groups = blk_crypto_attr_groups,
+	.sysfs_ops	= &blk_crypto_attr_ops,
+	.release	= blk_crypto_release,
+};
+
+/*
+ * If the request_queue has a blk_crypto_profile, create the "crypto"
+ * subdirectory in sysfs (/sys/block/$disk/queue/crypto/).
+ */
+int blk_crypto_sysfs_register(struct gendisk *disk)
+{
+	struct request_queue *q = disk->queue;
+	struct blk_crypto_kobj *obj;
+	int err;
+
+	if (!q->crypto_profile)
+		return 0;
+
+	obj = kzalloc_obj(*obj);
+	if (!obj)
+		return -ENOMEM;
+	obj->profile = q->crypto_profile;
+
+	err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype,
+				   &disk->queue_kobj, "crypto");
+	if (err) {
+		kobject_put(&obj->kobj);
+		return err;
+	}
+	q->crypto_kobject = &obj->kobj;
+	return 0;
+}
+
+void blk_crypto_sysfs_unregister(struct gendisk *disk)
+{
+	kobject_put(disk->queue->crypto_kobject);
+}
+
+static int __init blk_crypto_sysfs_init(void)
+{
+	int i;
+
+	BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);
+	for (i = 1; i < BLK_ENCRYPTION_MODE_MAX; i++) {
+		struct blk_crypto_attr *attr = &__blk_crypto_mode_attrs[i];
+
+		attr->attr.name = blk_crypto_modes[i].name;
+		attr->attr.mode = 0444;
+		attr->show = blk_crypto_mode_show;
+		blk_crypto_mode_attrs[i - 1] = &attr->attr;
+	}
+	return 0;
+}
+subsys_initcall(blk_crypto_sysfs_init);