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, 144 insertions, 0 deletions

diff --git a/crypto/geniv.c b/crypto/geniv.c
new file mode 100644
index 000000000..04befe3a7
--- /dev/null
+++ b/crypto/geniv.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * geniv: Shared IV generator code
+ *
+ * This file provides common code to IV generators such as seqiv.
+ *
+ * Copyright (c) 2007-2019 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <crypto/internal/geniv.h>
+#include <crypto/internal/rng.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+
+static int aead_geniv_setkey(struct crypto_aead *tfm,
+			     const u8 *key, unsigned int keylen)
+{
+	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
+
+	return crypto_aead_setkey(ctx->child, key, keylen);
+}
+
+static int aead_geniv_setauthsize(struct crypto_aead *tfm,
+				  unsigned int authsize)
+{
+	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
+
+	return crypto_aead_setauthsize(ctx->child, authsize);
+}
+
+static void aead_geniv_free(struct aead_instance *inst)
+{
+	crypto_drop_aead(aead_instance_ctx(inst));
+	kfree(inst);
+}
+
+struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
+				       struct rtattr **tb)
+{
+	struct crypto_aead_spawn *spawn;
+	struct aead_instance *inst;
+	struct aead_alg *alg;
+	unsigned int ivsize;
+	unsigned int maxauthsize;
+	u32 mask;
+	int err;
+
+	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
+	if (err)
+		return ERR_PTR(err);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+	if (!inst)
+		return ERR_PTR(-ENOMEM);
+
+	spawn = aead_instance_ctx(inst);
+
+	err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
+			       crypto_attr_alg_name(tb[1]), 0, mask);
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_spawn_aead_alg(spawn);
+
+	ivsize = crypto_aead_alg_ivsize(alg);
+	maxauthsize = crypto_aead_alg_maxauthsize(alg);
+
+	err = -EINVAL;
+	if (ivsize < sizeof(u64))
+		goto err_free_inst;
+
+	err = -ENAMETOOLONG;
+	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
+		     "%s(%s)", tmpl->name, alg->base.cra_name) >=
+	    CRYPTO_MAX_ALG_NAME)
+		goto err_free_inst;
+	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+		     "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
+	    CRYPTO_MAX_ALG_NAME)
+		goto err_free_inst;
+
+	inst->alg.base.cra_priority = alg->base.cra_priority;
+	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
+	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
+	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
+
+	inst->alg.setkey = aead_geniv_setkey;
+	inst->alg.setauthsize = aead_geniv_setauthsize;
+
+	inst->alg.ivsize = ivsize;
+	inst->alg.maxauthsize = maxauthsize;
+
+	inst->free = aead_geniv_free;
+
+out:
+	return inst;
+
+err_free_inst:
+	aead_geniv_free(inst);
+	inst = ERR_PTR(err);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(aead_geniv_alloc);
+
+int aead_init_geniv(struct crypto_aead *aead)
+{
+	struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
+	struct aead_instance *inst = aead_alg_instance(aead);
+	struct crypto_aead *child;
+	int err;
+
+	err = crypto_stdrng_get_bytes(ctx->salt, crypto_aead_ivsize(aead));
+	if (err)
+		goto out;
+
+	child = crypto_spawn_aead(aead_instance_ctx(inst));
+	err = PTR_ERR(child);
+	if (IS_ERR(child))
+		goto out;
+
+	ctx->child = child;
+	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
+				      sizeof(struct aead_request));
+
+	err = 0;
+
+out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(aead_init_geniv);
+
+void aead_exit_geniv(struct crypto_aead *tfm)
+{
+	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
+
+	crypto_free_aead(ctx->child);
+}
+EXPORT_SYMBOL_GPL(aead_exit_geniv);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Shared IV generator code");