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, 315 insertions, 0 deletions

diff --git a/crypto/zstd.c b/crypto/zstd.c
new file mode 100644
index 000000000..556f5d2bd
--- /dev/null
+++ b/crypto/zstd.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Cryptographic API.
+ *
+ * Copyright (c) 2017-present, Facebook, Inc.
+ */
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/overflow.h>
+#include <linux/vmalloc.h>
+#include <linux/zstd.h>
+#include <crypto/internal/acompress.h>
+#include <crypto/scatterwalk.h>
+
+
+#define ZSTD_DEF_LEVEL		3
+#define ZSTD_MAX_WINDOWLOG	18
+#define ZSTD_MAX_SIZE		BIT(ZSTD_MAX_WINDOWLOG)
+
+struct zstd_ctx {
+	zstd_cctx *cctx;
+	zstd_dctx *dctx;
+	size_t wksp_size;
+	zstd_parameters params;
+	u8 wksp[] __aligned(8) __counted_by(wksp_size);
+};
+
+static DEFINE_MUTEX(zstd_stream_lock);
+
+static void *zstd_alloc_stream(void)
+{
+	zstd_parameters params;
+	struct zstd_ctx *ctx;
+	size_t wksp_size;
+
+	params = zstd_get_params(ZSTD_DEF_LEVEL, ZSTD_MAX_SIZE);
+
+	wksp_size = max(zstd_cstream_workspace_bound(&params.cParams),
+			zstd_dstream_workspace_bound(ZSTD_MAX_SIZE));
+	if (!wksp_size)
+		return ERR_PTR(-EINVAL);
+
+	ctx = kvmalloc_flex(*ctx, wksp, wksp_size);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	ctx->params = params;
+	ctx->wksp_size = wksp_size;
+
+	return ctx;
+}
+
+static void zstd_free_stream(void *ctx)
+{
+	kvfree(ctx);
+}
+
+static struct crypto_acomp_streams zstd_streams = {
+	.alloc_ctx = zstd_alloc_stream,
+	.free_ctx = zstd_free_stream,
+};
+
+static int zstd_init(struct crypto_acomp *acomp_tfm)
+{
+	int ret = 0;
+
+	mutex_lock(&zstd_stream_lock);
+	ret = crypto_acomp_alloc_streams(&zstd_streams);
+	mutex_unlock(&zstd_stream_lock);
+
+	return ret;
+}
+
+static int zstd_compress_one(struct acomp_req *req, struct zstd_ctx *ctx,
+			     const void *src, void *dst, unsigned int *dlen)
+{
+	size_t out_len;
+
+	ctx->cctx = zstd_init_cctx(ctx->wksp, ctx->wksp_size);
+	if (!ctx->cctx)
+		return -EINVAL;
+
+	out_len = zstd_compress_cctx(ctx->cctx, dst, req->dlen, src, req->slen,
+				     &ctx->params);
+	if (zstd_is_error(out_len))
+		return -EINVAL;
+
+	*dlen = out_len;
+
+	return 0;
+}
+
+static int zstd_compress(struct acomp_req *req)
+{
+	struct crypto_acomp_stream *s;
+	unsigned int pos, scur, dcur;
+	unsigned int total_out = 0;
+	bool data_available = true;
+	zstd_out_buffer outbuf;
+	struct acomp_walk walk;
+	zstd_in_buffer inbuf;
+	struct zstd_ctx *ctx;
+	size_t pending_bytes;
+	size_t num_bytes;
+	int ret;
+
+	s = crypto_acomp_lock_stream_bh(&zstd_streams);
+	ctx = s->ctx;
+
+	ret = acomp_walk_virt(&walk, req, true);
+	if (ret)
+		goto out;
+
+	ctx->cctx = zstd_init_cstream(&ctx->params, 0, ctx->wksp, ctx->wksp_size);
+	if (!ctx->cctx) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	do {
+		dcur = acomp_walk_next_dst(&walk);
+		if (!dcur) {
+			ret = -ENOSPC;
+			goto out;
+		}
+
+		outbuf.pos = 0;
+		outbuf.dst = (u8 *)walk.dst.virt.addr;
+		outbuf.size = dcur;
+
+		do {
+			scur = acomp_walk_next_src(&walk);
+			if (dcur == req->dlen && scur == req->slen) {
+				ret = zstd_compress_one(req, ctx, walk.src.virt.addr,
+							walk.dst.virt.addr, &total_out);
+				acomp_walk_done_src(&walk, scur);
+				acomp_walk_done_dst(&walk, dcur);
+				goto out;
+			}
+
+			if (scur) {
+				inbuf.pos = 0;
+				inbuf.src = walk.src.virt.addr;
+				inbuf.size = scur;
+			} else {
+				data_available = false;
+				break;
+			}
+
+			num_bytes = zstd_compress_stream(ctx->cctx, &outbuf, &inbuf);
+			if (ZSTD_isError(num_bytes)) {
+				ret = -EIO;
+				goto out;
+			}
+
+			pending_bytes = zstd_flush_stream(ctx->cctx, &outbuf);
+			if (ZSTD_isError(pending_bytes)) {
+				ret = -EIO;
+				goto out;
+			}
+			acomp_walk_done_src(&walk, inbuf.pos);
+		} while (dcur != outbuf.pos);
+
+		total_out += outbuf.pos;
+		acomp_walk_done_dst(&walk, dcur);
+	} while (data_available);
+
+	pos = outbuf.pos;
+	num_bytes = zstd_end_stream(ctx->cctx, &outbuf);
+	if (ZSTD_isError(num_bytes))
+		ret = -EIO;
+	else
+		total_out += (outbuf.pos - pos);
+
+out:
+	if (ret)
+		req->dlen = 0;
+	else
+		req->dlen = total_out;
+
+	crypto_acomp_unlock_stream_bh(s);
+
+	return ret;
+}
+
+static int zstd_decompress_one(struct acomp_req *req, struct zstd_ctx *ctx,
+			       const void *src, void *dst, unsigned int *dlen)
+{
+	size_t out_len;
+
+	ctx->dctx = zstd_init_dctx(ctx->wksp, ctx->wksp_size);
+	if (!ctx->dctx)
+		return -EINVAL;
+
+	out_len = zstd_decompress_dctx(ctx->dctx, dst, req->dlen, src, req->slen);
+	if (zstd_is_error(out_len))
+		return -EINVAL;
+
+	*dlen = out_len;
+
+	return 0;
+}
+
+static int zstd_decompress(struct acomp_req *req)
+{
+	struct crypto_acomp_stream *s;
+	unsigned int total_out = 0;
+	unsigned int scur, dcur;
+	zstd_out_buffer outbuf;
+	struct acomp_walk walk;
+	zstd_in_buffer inbuf;
+	struct zstd_ctx *ctx;
+	size_t pending_bytes;
+	int ret;
+
+	s = crypto_acomp_lock_stream_bh(&zstd_streams);
+	ctx = s->ctx;
+
+	ret = acomp_walk_virt(&walk, req, true);
+	if (ret)
+		goto out;
+
+	ctx->dctx = zstd_init_dstream(ZSTD_MAX_SIZE, ctx->wksp, ctx->wksp_size);
+	if (!ctx->dctx) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	do {
+		scur = acomp_walk_next_src(&walk);
+		if (scur) {
+			inbuf.pos = 0;
+			inbuf.size = scur;
+			inbuf.src = walk.src.virt.addr;
+		} else {
+			break;
+		}
+
+		do {
+			dcur = acomp_walk_next_dst(&walk);
+			if (dcur == req->dlen && scur == req->slen) {
+				ret = zstd_decompress_one(req, ctx, walk.src.virt.addr,
+							  walk.dst.virt.addr, &total_out);
+				acomp_walk_done_dst(&walk, dcur);
+				acomp_walk_done_src(&walk, scur);
+				goto out;
+			}
+
+			if (!dcur) {
+				ret = -ENOSPC;
+				goto out;
+			}
+
+			outbuf.pos = 0;
+			outbuf.dst = (u8 *)walk.dst.virt.addr;
+			outbuf.size = dcur;
+
+			pending_bytes = zstd_decompress_stream(ctx->dctx, &outbuf, &inbuf);
+			if (ZSTD_isError(pending_bytes)) {
+				ret = -EIO;
+				goto out;
+			}
+
+			total_out += outbuf.pos;
+
+			acomp_walk_done_dst(&walk, outbuf.pos);
+		} while (inbuf.pos != scur);
+
+		acomp_walk_done_src(&walk, scur);
+	} while (ret == 0);
+
+out:
+	if (ret)
+		req->dlen = 0;
+	else
+		req->dlen = total_out;
+
+	crypto_acomp_unlock_stream_bh(s);
+
+	return ret;
+}
+
+static struct acomp_alg zstd_acomp = {
+	.base = {
+		.cra_name = "zstd",
+		.cra_driver_name = "zstd-generic",
+		.cra_flags = CRYPTO_ALG_REQ_VIRT,
+		.cra_module = THIS_MODULE,
+	},
+	.init = zstd_init,
+	.compress = zstd_compress,
+	.decompress = zstd_decompress,
+};
+
+static int __init zstd_mod_init(void)
+{
+	return crypto_register_acomp(&zstd_acomp);
+}
+
+static void __exit zstd_mod_fini(void)
+{
+	crypto_unregister_acomp(&zstd_acomp);
+	crypto_acomp_free_streams(&zstd_streams);
+}
+
+module_init(zstd_mod_init);
+module_exit(zstd_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Zstd Compression Algorithm");
+MODULE_ALIAS_CRYPTO("zstd");