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, 103 insertions, 0 deletions

diff --git a/crypto/proc.c b/crypto/proc.c
new file mode 100644
index 000000000..5fb9fe86d
--- /dev/null
+++ b/crypto/proc.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Scatterlist Cryptographic API.
+ *
+ * Procfs information.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/atomic.h>
+#include <linux/init.h>
+#include <linux/crypto.h>
+#include <linux/fips.h>
+#include <linux/module.h>	/* for module_name() */
+#include <linux/rwsem.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+	__acquires_shared(&crypto_alg_sem)
+{
+	down_read(&crypto_alg_sem);
+	return seq_list_start(&crypto_alg_list, *pos);
+}
+
+static void *c_next(struct seq_file *m, void *p, loff_t *pos)
+	__must_hold_shared(&crypto_alg_sem)
+{
+	return seq_list_next(p, &crypto_alg_list, pos);
+}
+
+static void c_stop(struct seq_file *m, void *p)
+	__releases_shared(&crypto_alg_sem)
+{
+	up_read(&crypto_alg_sem);
+}
+
+static int c_show(struct seq_file *m, void *p)
+{
+	struct crypto_alg *alg = list_entry(p, struct crypto_alg, cra_list);
+
+	seq_printf(m, "name         : %s\n", alg->cra_name);
+	seq_printf(m, "driver       : %s\n", alg->cra_driver_name);
+	seq_printf(m, "module       : %s\n", module_name(alg->cra_module));
+	seq_printf(m, "priority     : %d\n", alg->cra_priority);
+	seq_printf(m, "refcnt       : %u\n", refcount_read(&alg->cra_refcnt));
+	seq_printf(m, "selftest     : %s\n",
+		   (alg->cra_flags & CRYPTO_ALG_TESTED) ?
+		   "passed" : "unknown");
+	seq_printf(m, "internal     : %s\n",
+		   str_yes_no(alg->cra_flags & CRYPTO_ALG_INTERNAL));
+	if (fips_enabled)
+		seq_printf(m, "fips         : %s\n",
+			str_no_yes(alg->cra_flags & CRYPTO_ALG_FIPS_INTERNAL));
+
+	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
+		seq_printf(m, "type         : larval\n");
+		seq_printf(m, "flags        : 0x%x\n", alg->cra_flags);
+		goto out;
+	}
+
+	if (alg->cra_type && alg->cra_type->show) {
+		alg->cra_type->show(m, alg);
+		goto out;
+	}
+
+	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
+	case CRYPTO_ALG_TYPE_CIPHER:
+		seq_printf(m, "type         : cipher\n");
+		seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
+		seq_printf(m, "min keysize  : %u\n",
+					alg->cra_cipher.cia_min_keysize);
+		seq_printf(m, "max keysize  : %u\n",
+					alg->cra_cipher.cia_max_keysize);
+		break;
+	default:
+		seq_printf(m, "type         : unknown\n");
+		break;
+	}
+
+out:
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static const struct seq_operations crypto_seq_ops = {
+	.start		= c_start,
+	.next		= c_next,
+	.stop		= c_stop,
+	.show		= c_show
+};
+
+void __init crypto_init_proc(void)
+{
+	proc_create_seq("crypto", 0, NULL, &crypto_seq_ops);
+}
+
+void __exit crypto_exit_proc(void)
+{
+	remove_proc_entry("crypto", NULL);
+}