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, 101 insertions, 0 deletions

diff --git a/crypto/lzo.c b/crypto/lzo.c
new file mode 100644
index 000000000..d43242b24
--- /dev/null
+++ b/crypto/lzo.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Cryptographic API.
+ */
+
+#include <crypto/internal/scompress.h>
+#include <linux/init.h>
+#include <linux/lzo.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+static void *lzo_alloc_ctx(void)
+{
+	void *ctx;
+
+	ctx = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	return ctx;
+}
+
+static void lzo_free_ctx(void *ctx)
+{
+	kvfree(ctx);
+}
+
+static int __lzo_compress(const u8 *src, unsigned int slen,
+			  u8 *dst, unsigned int *dlen, void *ctx)
+{
+	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
+	int err;
+
+	err = lzo1x_1_compress_safe(src, slen, dst, &tmp_len, ctx);
+
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	*dlen = tmp_len;
+	return 0;
+}
+
+static int lzo_scompress(struct crypto_scomp *tfm, const u8 *src,
+			 unsigned int slen, u8 *dst, unsigned int *dlen,
+			 void *ctx)
+{
+	return __lzo_compress(src, slen, dst, dlen, ctx);
+}
+
+static int __lzo_decompress(const u8 *src, unsigned int slen,
+			    u8 *dst, unsigned int *dlen)
+{
+	int err;
+	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
+
+	err = lzo1x_decompress_safe(src, slen, dst, &tmp_len);
+
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	*dlen = tmp_len;
+	return 0;
+}
+
+static int lzo_sdecompress(struct crypto_scomp *tfm, const u8 *src,
+			   unsigned int slen, u8 *dst, unsigned int *dlen,
+			   void *ctx)
+{
+	return __lzo_decompress(src, slen, dst, dlen);
+}
+
+static struct scomp_alg scomp = {
+	.streams		= {
+		.alloc_ctx	= lzo_alloc_ctx,
+		.free_ctx	= lzo_free_ctx,
+	},
+	.compress		= lzo_scompress,
+	.decompress		= lzo_sdecompress,
+	.base			= {
+		.cra_name	= "lzo",
+		.cra_driver_name = "lzo-scomp",
+		.cra_module	 = THIS_MODULE,
+	}
+};
+
+static int __init lzo_mod_init(void)
+{
+	return crypto_register_scomp(&scomp);
+}
+
+static void __exit lzo_mod_fini(void)
+{
+	crypto_unregister_scomp(&scomp);
+}
+
+module_init(lzo_mod_init);
+module_exit(lzo_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO Compression Algorithm");
+MODULE_ALIAS_CRYPTO("lzo");