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, 342 insertions, 0 deletions

diff --git a/block/blk-integrity.c b/block/blk-integrity.c
new file mode 100644
index 000000000..964eebbee
--- /dev/null
+++ b/block/blk-integrity.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * blk-integrity.c - Block layer data integrity extensions
+ *
+ * Copyright (C) 2007, 2008 Oracle Corporation
+ * Written by: Martin K. Petersen <martin.petersen@oracle.com>
+ */
+
+#include <linux/blk-integrity.h>
+#include <linux/backing-dev.h>
+#include <linux/mempool.h>
+#include <linux/bio.h>
+#include <linux/scatterlist.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/t10-pi.h>
+
+#include "blk.h"
+
+/**
+ * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
+ * @q:		request queue
+ * @bio:	bio with integrity metadata attached
+ *
+ * Description: Returns the number of elements required in a
+ * scatterlist corresponding to the integrity metadata in a bio.
+ */
+int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
+{
+	struct bio_vec iv, ivprv = { NULL };
+	unsigned int segments = 0;
+	unsigned int seg_size = 0;
+	struct bvec_iter iter;
+	int prev = 0;
+
+	bio_for_each_integrity_vec(iv, bio, iter) {
+
+		if (prev) {
+			if (!biovec_phys_mergeable(q, &ivprv, &iv))
+				goto new_segment;
+			if (seg_size + iv.bv_len > queue_max_segment_size(q))
+				goto new_segment;
+
+			seg_size += iv.bv_len;
+		} else {
+new_segment:
+			segments++;
+			seg_size = iv.bv_len;
+		}
+
+		prev = 1;
+		ivprv = iv;
+	}
+
+	return segments;
+}
+
+int blk_get_meta_cap(struct block_device *bdev, unsigned int cmd,
+		     struct logical_block_metadata_cap __user *argp)
+{
+	struct blk_integrity *bi;
+	struct logical_block_metadata_cap meta_cap = {};
+	size_t usize = _IOC_SIZE(cmd);
+
+	if (!extensible_ioctl_valid(cmd, FS_IOC_GETLBMD_CAP, LBMD_SIZE_VER0))
+		return -ENOIOCTLCMD;
+
+	bi = blk_get_integrity(bdev->bd_disk);
+	if (!bi)
+		goto out;
+
+	if (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE)
+		meta_cap.lbmd_flags |= LBMD_PI_CAP_INTEGRITY;
+	if (bi->flags & BLK_INTEGRITY_REF_TAG)
+		meta_cap.lbmd_flags |= LBMD_PI_CAP_REFTAG;
+	meta_cap.lbmd_interval = 1 << bi->interval_exp;
+	meta_cap.lbmd_size = bi->metadata_size;
+	meta_cap.lbmd_pi_size = bi->pi_tuple_size;
+	meta_cap.lbmd_pi_offset = bi->pi_offset;
+	meta_cap.lbmd_opaque_size = bi->metadata_size - bi->pi_tuple_size;
+	if (meta_cap.lbmd_opaque_size && !bi->pi_offset)
+		meta_cap.lbmd_opaque_offset = bi->pi_tuple_size;
+
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_NONE:
+		meta_cap.lbmd_guard_tag_type = LBMD_PI_CSUM_NONE;
+		break;
+	case BLK_INTEGRITY_CSUM_IP:
+		meta_cap.lbmd_guard_tag_type = LBMD_PI_CSUM_IP;
+		break;
+	case BLK_INTEGRITY_CSUM_CRC:
+		meta_cap.lbmd_guard_tag_type = LBMD_PI_CSUM_CRC16_T10DIF;
+		break;
+	case BLK_INTEGRITY_CSUM_CRC64:
+		meta_cap.lbmd_guard_tag_type = LBMD_PI_CSUM_CRC64_NVME;
+		break;
+	}
+
+	if (bi->csum_type != BLK_INTEGRITY_CSUM_NONE)
+		meta_cap.lbmd_app_tag_size = 2;
+
+	if (bi->flags & BLK_INTEGRITY_REF_TAG) {
+		switch (bi->csum_type) {
+		case BLK_INTEGRITY_CSUM_CRC64:
+			meta_cap.lbmd_ref_tag_size =
+				sizeof_field(struct crc64_pi_tuple, ref_tag);
+			break;
+		case BLK_INTEGRITY_CSUM_CRC:
+		case BLK_INTEGRITY_CSUM_IP:
+			meta_cap.lbmd_ref_tag_size =
+				sizeof_field(struct t10_pi_tuple, ref_tag);
+			break;
+		default:
+			break;
+		}
+	}
+
+out:
+	return copy_struct_to_user(argp, usize, &meta_cap, sizeof(meta_cap),
+				   NULL);
+}
+
+int blk_rq_integrity_map_user(struct request *rq, void __user *ubuf,
+			      ssize_t bytes)
+{
+	int ret;
+	struct iov_iter iter;
+
+	iov_iter_ubuf(&iter, rq_data_dir(rq), ubuf, bytes);
+	ret = bio_integrity_map_user(rq->bio, &iter);
+	if (ret)
+		return ret;
+
+	rq->nr_integrity_segments = blk_rq_count_integrity_sg(rq->q, rq->bio);
+	rq->cmd_flags |= REQ_INTEGRITY;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(blk_rq_integrity_map_user);
+
+bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
+			    struct request *next)
+{
+	struct bio_integrity_payload *bip, *bip_next;
+
+	if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
+		return true;
+
+	if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
+		return false;
+
+	bip = bio_integrity(req->bio);
+	bip_next = bio_integrity(next->bio);
+	if (bip->bip_flags != bip_next->bip_flags)
+		return false;
+
+	if (bip->bip_flags & BIP_CHECK_APPTAG &&
+	    bip->app_tag != bip_next->app_tag)
+		return false;
+
+	if (req->nr_integrity_segments + next->nr_integrity_segments >
+	    q->limits.max_integrity_segments)
+		return false;
+
+	if (integrity_req_gap_back_merge(req, next->bio))
+		return false;
+
+	return true;
+}
+
+bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
+			     struct bio *bio)
+{
+	struct bio_integrity_payload *bip, *bip_bio = bio_integrity(bio);
+	int nr_integrity_segs;
+
+	if (blk_integrity_rq(req) == 0 && bip_bio == NULL)
+		return true;
+
+	if (blk_integrity_rq(req) == 0 || bip_bio == NULL)
+		return false;
+
+	bip = bio_integrity(req->bio);
+	if (bip->bip_flags != bip_bio->bip_flags)
+		return false;
+
+	if (bip->bip_flags & BIP_CHECK_APPTAG &&
+	    bip->app_tag != bip_bio->app_tag)
+		return false;
+
+	nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
+	if (req->nr_integrity_segments + nr_integrity_segs >
+	    q->limits.max_integrity_segments)
+		return false;
+
+	return true;
+}
+
+static inline struct blk_integrity *dev_to_bi(struct device *dev)
+{
+	return &dev_to_disk(dev)->queue->limits.integrity;
+}
+
+const char *blk_integrity_profile_name(struct blk_integrity *bi)
+{
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_IP:
+		if (bi->flags & BLK_INTEGRITY_REF_TAG)
+			return "T10-DIF-TYPE1-IP";
+		return "T10-DIF-TYPE3-IP";
+	case BLK_INTEGRITY_CSUM_CRC:
+		if (bi->flags & BLK_INTEGRITY_REF_TAG)
+			return "T10-DIF-TYPE1-CRC";
+		return "T10-DIF-TYPE3-CRC";
+	case BLK_INTEGRITY_CSUM_CRC64:
+		if (bi->flags & BLK_INTEGRITY_REF_TAG)
+			return "EXT-DIF-TYPE1-CRC64";
+		return "EXT-DIF-TYPE3-CRC64";
+	case BLK_INTEGRITY_CSUM_NONE:
+		break;
+	}
+
+	return "nop";
+}
+EXPORT_SYMBOL_GPL(blk_integrity_profile_name);
+
+static ssize_t flag_store(struct device *dev, const char *page, size_t count,
+		unsigned char flag)
+{
+	struct request_queue *q = dev_to_disk(dev)->queue;
+	struct queue_limits lim;
+	unsigned long val;
+	int err;
+
+	err = kstrtoul(page, 10, &val);
+	if (err)
+		return err;
+
+	/* note that the flags are inverted vs the values in the sysfs files */
+	lim = queue_limits_start_update(q);
+	if (val)
+		lim.integrity.flags &= ~flag;
+	else
+		lim.integrity.flags |= flag;
+
+	err = queue_limits_commit_update_frozen(q, &lim);
+	if (err)
+		return err;
+	return count;
+}
+
+static ssize_t flag_show(struct device *dev, char *page, unsigned char flag)
+{
+	struct blk_integrity *bi = dev_to_bi(dev);
+
+	return sysfs_emit(page, "%d\n", !(bi->flags & flag));
+}
+
+static ssize_t format_show(struct device *dev, struct device_attribute *attr,
+			   char *page)
+{
+	struct blk_integrity *bi = dev_to_bi(dev);
+
+	if (!bi->metadata_size)
+		return sysfs_emit(page, "none\n");
+	return sysfs_emit(page, "%s\n", blk_integrity_profile_name(bi));
+}
+
+static ssize_t tag_size_show(struct device *dev, struct device_attribute *attr,
+			     char *page)
+{
+	struct blk_integrity *bi = dev_to_bi(dev);
+
+	return sysfs_emit(page, "%u\n", bi->tag_size);
+}
+
+static ssize_t protection_interval_bytes_show(struct device *dev,
+					      struct device_attribute *attr,
+					      char *page)
+{
+	struct blk_integrity *bi = dev_to_bi(dev);
+
+	return sysfs_emit(page, "%u\n",
+			  bi->interval_exp ? 1 << bi->interval_exp : 0);
+}
+
+static ssize_t read_verify_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *page, size_t count)
+{
+	return flag_store(dev, page, count, BLK_INTEGRITY_NOVERIFY);
+}
+
+static ssize_t read_verify_show(struct device *dev,
+				struct device_attribute *attr, char *page)
+{
+	return flag_show(dev, page, BLK_INTEGRITY_NOVERIFY);
+}
+
+static ssize_t write_generate_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *page, size_t count)
+{
+	return flag_store(dev, page, count, BLK_INTEGRITY_NOGENERATE);
+}
+
+static ssize_t write_generate_show(struct device *dev,
+				   struct device_attribute *attr, char *page)
+{
+	return flag_show(dev, page, BLK_INTEGRITY_NOGENERATE);
+}
+
+static ssize_t device_is_integrity_capable_show(struct device *dev,
+						struct device_attribute *attr,
+						char *page)
+{
+	struct blk_integrity *bi = dev_to_bi(dev);
+
+	return sysfs_emit(page, "%u\n",
+			  !!(bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE));
+}
+
+static DEVICE_ATTR_RO(format);
+static DEVICE_ATTR_RO(tag_size);
+static DEVICE_ATTR_RO(protection_interval_bytes);
+static DEVICE_ATTR_RW(read_verify);
+static DEVICE_ATTR_RW(write_generate);
+static DEVICE_ATTR_RO(device_is_integrity_capable);
+
+static struct attribute *integrity_attrs[] = {
+	&dev_attr_format.attr,
+	&dev_attr_tag_size.attr,
+	&dev_attr_protection_interval_bytes.attr,
+	&dev_attr_read_verify.attr,
+	&dev_attr_write_generate.attr,
+	&dev_attr_device_is_integrity_capable.attr,
+	NULL
+};
+
+const struct attribute_group blk_integrity_attr_group = {
+	.name = "integrity",
+	.attrs = integrity_attrs,
+};