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, 225 insertions, 0 deletions

diff --git a/drivers/crypto/omap-crypto.c b/drivers/crypto/omap-crypto.c
new file mode 100644
index 000000000..7bd6869c2
--- /dev/null
+++ b/drivers/crypto/omap-crypto.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP Crypto driver common support routines.
+ *
+ * Copyright (c) 2017 Texas Instruments Incorporated
+ *   Tero Kristo <t-kristo@ti.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/scatterlist.h>
+#include <crypto/scatterwalk.h>
+
+#include "omap-crypto.h"
+
+static int omap_crypto_copy_sg_lists(int total, int bs,
+				     struct scatterlist **sg,
+				     struct scatterlist *new_sg, u16 flags)
+{
+	int n = sg_nents(*sg);
+	struct scatterlist *tmp;
+
+	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY)) {
+		new_sg = kmalloc_objs(*new_sg, n);
+		if (!new_sg)
+			return -ENOMEM;
+
+		sg_init_table(new_sg, n);
+	}
+
+	tmp = new_sg;
+
+	while (*sg && total) {
+		int len = (*sg)->length;
+
+		if (total < len)
+			len = total;
+
+		if (len > 0) {
+			total -= len;
+			sg_set_page(tmp, sg_page(*sg), len, (*sg)->offset);
+			if (total <= 0)
+				sg_mark_end(tmp);
+			tmp = sg_next(tmp);
+		}
+
+		*sg = sg_next(*sg);
+	}
+
+	*sg = new_sg;
+
+	return 0;
+}
+
+static int omap_crypto_copy_sgs(int total, int bs, struct scatterlist **sg,
+				struct scatterlist *new_sg, u16 flags)
+{
+	void *buf;
+	int pages;
+	int new_len;
+
+	new_len = ALIGN(total, bs);
+	pages = get_order(new_len);
+
+	buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
+	if (!buf) {
+		pr_err("%s: Couldn't allocate pages for unaligned cases.\n",
+		       __func__);
+		return -ENOMEM;
+	}
+
+	if (flags & OMAP_CRYPTO_COPY_DATA) {
+		scatterwalk_map_and_copy(buf, *sg, 0, total, 0);
+		if (flags & OMAP_CRYPTO_ZERO_BUF)
+			memset(buf + total, 0, new_len - total);
+	}
+
+	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
+		sg_init_table(new_sg, 1);
+
+	sg_set_buf(new_sg, buf, new_len);
+
+	*sg = new_sg;
+
+	return 0;
+}
+
+static int omap_crypto_check_sg(struct scatterlist *sg, int total, int bs,
+				u16 flags)
+{
+	int len = 0;
+	int num_sg = 0;
+
+	if (!IS_ALIGNED(total, bs))
+		return OMAP_CRYPTO_NOT_ALIGNED;
+
+	while (sg) {
+		num_sg++;
+
+		if (!IS_ALIGNED(sg->offset, 4))
+			return OMAP_CRYPTO_NOT_ALIGNED;
+		if (!IS_ALIGNED(sg->length, bs))
+			return OMAP_CRYPTO_NOT_ALIGNED;
+#ifdef CONFIG_ZONE_DMA
+		if (page_zonenum(sg_page(sg)) != ZONE_DMA)
+			return OMAP_CRYPTO_NOT_ALIGNED;
+#endif
+
+		len += sg->length;
+		sg = sg_next(sg);
+
+		if (len >= total)
+			break;
+	}
+
+	if ((flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) && num_sg > 1)
+		return OMAP_CRYPTO_NOT_ALIGNED;
+
+	if (len != total)
+		return OMAP_CRYPTO_BAD_DATA_LENGTH;
+
+	return 0;
+}
+
+int omap_crypto_align_sg(struct scatterlist **sg, int total, int bs,
+			 struct scatterlist *new_sg, u16 flags,
+			 u8 flags_shift, unsigned long *dd_flags)
+{
+	int ret;
+
+	*dd_flags &= ~(OMAP_CRYPTO_COPY_MASK << flags_shift);
+
+	if (flags & OMAP_CRYPTO_FORCE_COPY)
+		ret = OMAP_CRYPTO_NOT_ALIGNED;
+	else
+		ret = omap_crypto_check_sg(*sg, total, bs, flags);
+
+	if (ret == OMAP_CRYPTO_NOT_ALIGNED) {
+		ret = omap_crypto_copy_sgs(total, bs, sg, new_sg, flags);
+		if (ret)
+			return ret;
+		*dd_flags |= OMAP_CRYPTO_DATA_COPIED << flags_shift;
+	} else if (ret == OMAP_CRYPTO_BAD_DATA_LENGTH) {
+		ret = omap_crypto_copy_sg_lists(total, bs, sg, new_sg, flags);
+		if (ret)
+			return ret;
+		if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
+			*dd_flags |= OMAP_CRYPTO_SG_COPIED << flags_shift;
+	} else if (flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) {
+		sg_set_buf(new_sg, sg_virt(*sg), (*sg)->length);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(omap_crypto_align_sg);
+
+static void omap_crypto_copy_data(struct scatterlist *src,
+				  struct scatterlist *dst,
+				  int offset, int len)
+{
+	int amt;
+	void *srcb, *dstb;
+	int srco = 0, dsto = offset;
+
+	while (src && dst && len) {
+		if (srco >= src->length) {
+			srco -= src->length;
+			src = sg_next(src);
+			continue;
+		}
+
+		if (dsto >= dst->length) {
+			dsto -= dst->length;
+			dst = sg_next(dst);
+			continue;
+		}
+
+		amt = min(src->length - srco, dst->length - dsto);
+		amt = min(len, amt);
+
+		srcb = kmap_atomic(sg_page(src)) + srco + src->offset;
+		dstb = kmap_atomic(sg_page(dst)) + dsto + dst->offset;
+
+		memcpy(dstb, srcb, amt);
+
+		flush_dcache_page(sg_page(dst));
+
+		kunmap_atomic(srcb);
+		kunmap_atomic(dstb);
+
+		srco += amt;
+		dsto += amt;
+		len -= amt;
+	}
+}
+
+void omap_crypto_cleanup(struct scatterlist *sg, struct scatterlist *orig,
+			 int offset, int len, u8 flags_shift,
+			 unsigned long flags)
+{
+	void *buf;
+	int pages;
+
+	flags >>= flags_shift;
+	flags &= OMAP_CRYPTO_COPY_MASK;
+
+	if (!flags)
+		return;
+
+	buf = sg_virt(sg);
+	pages = get_order(len);
+
+	if (orig && (flags & OMAP_CRYPTO_DATA_COPIED))
+		omap_crypto_copy_data(sg, orig, offset, len);
+
+	if (flags & OMAP_CRYPTO_DATA_COPIED)
+		free_pages((unsigned long)buf, pages);
+	else if (flags & OMAP_CRYPTO_SG_COPIED)
+		kfree(sg);
+}
+EXPORT_SYMBOL_GPL(omap_crypto_cleanup);
+
+MODULE_DESCRIPTION("OMAP crypto support library.");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");