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, 111 insertions, 0 deletions

diff --git a/crypto/blake2b.c b/crypto/blake2b.c
new file mode 100644
index 000000000..67a6dae43
--- /dev/null
+++ b/crypto/blake2b.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Crypto API support for BLAKE2b
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <crypto/blake2b.h>
+#include <crypto/internal/hash.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+struct blake2b_tfm_ctx {
+	unsigned int keylen;
+	u8 key[BLAKE2B_KEY_SIZE];
+};
+
+static int crypto_blake2b_setkey(struct crypto_shash *tfm,
+				 const u8 *key, unsigned int keylen)
+{
+	struct blake2b_tfm_ctx *tctx = crypto_shash_ctx(tfm);
+
+	if (keylen > BLAKE2B_KEY_SIZE)
+		return -EINVAL;
+	memcpy(tctx->key, key, keylen);
+	tctx->keylen = keylen;
+	return 0;
+}
+
+#define BLAKE2B_CTX(desc) ((struct blake2b_ctx *)shash_desc_ctx(desc))
+
+static int crypto_blake2b_init(struct shash_desc *desc)
+{
+	const struct blake2b_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+	unsigned int digestsize = crypto_shash_digestsize(desc->tfm);
+
+	blake2b_init_key(BLAKE2B_CTX(desc), digestsize,
+			 tctx->key, tctx->keylen);
+	return 0;
+}
+
+static int crypto_blake2b_update(struct shash_desc *desc,
+				 const u8 *data, unsigned int len)
+{
+	blake2b_update(BLAKE2B_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_blake2b_final(struct shash_desc *desc, u8 *out)
+{
+	blake2b_final(BLAKE2B_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_blake2b_digest(struct shash_desc *desc,
+				 const u8 *data, unsigned int len, u8 *out)
+{
+	const struct blake2b_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+	unsigned int digestsize = crypto_shash_digestsize(desc->tfm);
+
+	blake2b(tctx->key, tctx->keylen, data, len, out, digestsize);
+	return 0;
+}
+
+#define BLAKE2B_ALG(name, digest_size)					\
+	{								\
+		.base.cra_name		= name,				\
+		.base.cra_driver_name	= name "-lib",			\
+		.base.cra_priority	= 300,				\
+		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,	\
+		.base.cra_blocksize	= BLAKE2B_BLOCK_SIZE,		\
+		.base.cra_ctxsize	= sizeof(struct blake2b_tfm_ctx), \
+		.base.cra_module	= THIS_MODULE,			\
+		.digestsize		= digest_size,			\
+		.setkey			= crypto_blake2b_setkey,	\
+		.init			= crypto_blake2b_init,		\
+		.update			= crypto_blake2b_update,	\
+		.final			= crypto_blake2b_final,		\
+		.digest			= crypto_blake2b_digest,	\
+		.descsize		= sizeof(struct blake2b_ctx),	\
+	}
+
+static struct shash_alg algs[] = {
+	BLAKE2B_ALG("blake2b-160", BLAKE2B_160_HASH_SIZE),
+	BLAKE2B_ALG("blake2b-256", BLAKE2B_256_HASH_SIZE),
+	BLAKE2B_ALG("blake2b-384", BLAKE2B_384_HASH_SIZE),
+	BLAKE2B_ALG("blake2b-512", BLAKE2B_512_HASH_SIZE),
+};
+
+static int __init crypto_blake2b_mod_init(void)
+{
+	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
+}
+module_init(crypto_blake2b_mod_init);
+
+static void __exit crypto_blake2b_mod_exit(void)
+{
+	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
+}
+module_exit(crypto_blake2b_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Crypto API support for BLAKE2b");
+
+MODULE_ALIAS_CRYPTO("blake2b-160");
+MODULE_ALIAS_CRYPTO("blake2b-160-lib");
+MODULE_ALIAS_CRYPTO("blake2b-256");
+MODULE_ALIAS_CRYPTO("blake2b-256-lib");
+MODULE_ALIAS_CRYPTO("blake2b-384");
+MODULE_ALIAS_CRYPTO("blake2b-384-lib");
+MODULE_ALIAS_CRYPTO("blake2b-512");
+MODULE_ALIAS_CRYPTO("blake2b-512-lib");