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, 407 insertions, 0 deletions

diff --git a/block/partitions/ibm.c b/block/partitions/ibm.c
new file mode 100644
index 000000000..54047e722
--- /dev/null
+++ b/block/partitions/ibm.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
+ *                  Volker Sameske <sameske@de.ibm.com>
+ * Bugreports.to..: <Linux390@de.ibm.com>
+ * Copyright IBM Corp. 1999, 2012
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/hdreg.h>
+#include <linux/slab.h>
+#include <asm/dasd.h>
+#include <asm/ebcdic.h>
+#include <linux/uaccess.h>
+#include <asm/vtoc.h>
+#include <linux/module.h>
+#include <linux/dasd_mod.h>
+
+#include "check.h"
+
+union label_t {
+	struct vtoc_volume_label_cdl vol;
+	struct vtoc_volume_label_ldl lnx;
+	struct vtoc_cms_label cms;
+};
+
+/*
+ * compute the block number from a
+ * cyl-cyl-head-head structure
+ */
+static sector_t cchh2blk(struct vtoc_cchh *ptr, struct hd_geometry *geo)
+{
+	sector_t cyl;
+	__u16 head;
+
+	/* decode cylinder and heads for large volumes */
+	cyl = ptr->hh & 0xFFF0;
+	cyl <<= 12;
+	cyl |= ptr->cc;
+	head = ptr->hh & 0x000F;
+	return cyl * geo->heads * geo->sectors +
+	       head * geo->sectors;
+}
+
+/*
+ * compute the block number from a
+ * cyl-cyl-head-head-block structure
+ */
+static sector_t cchhb2blk(struct vtoc_cchhb *ptr, struct hd_geometry *geo)
+{
+	sector_t cyl;
+	__u16 head;
+
+	/* decode cylinder and heads for large volumes */
+	cyl = ptr->hh & 0xFFF0;
+	cyl <<= 12;
+	cyl |= ptr->cc;
+	head = ptr->hh & 0x000F;
+	return	cyl * geo->heads * geo->sectors +
+		head * geo->sectors +
+		ptr->b;
+}
+
+/* Volume Label Type/ID Length */
+#define DASD_VOL_TYPE_LEN	4
+#define DASD_VOL_ID_LEN		6
+
+/* Volume Label Types */
+#define DASD_VOLLBL_TYPE_VOL1 0
+#define DASD_VOLLBL_TYPE_LNX1 1
+#define DASD_VOLLBL_TYPE_CMS1 2
+
+struct dasd_vollabel {
+	char *type;
+	int idx;
+};
+
+static struct dasd_vollabel dasd_vollabels[] = {
+	[DASD_VOLLBL_TYPE_VOL1] = {
+		.type = "VOL1",
+		.idx = DASD_VOLLBL_TYPE_VOL1,
+	},
+	[DASD_VOLLBL_TYPE_LNX1] = {
+		.type = "LNX1",
+		.idx = DASD_VOLLBL_TYPE_LNX1,
+	},
+	[DASD_VOLLBL_TYPE_CMS1] = {
+		.type = "CMS1",
+		.idx = DASD_VOLLBL_TYPE_CMS1,
+	},
+};
+
+static int get_label_by_type(const char *type)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dasd_vollabels); i++) {
+		if (!memcmp(type, dasd_vollabels[i].type, DASD_VOL_TYPE_LEN))
+			return dasd_vollabels[i].idx;
+	}
+
+	return -1;
+}
+
+static int find_label(struct parsed_partitions *state,
+		      dasd_information2_t *info,
+		      struct hd_geometry *geo,
+		      int blocksize,
+		      sector_t *labelsect,
+		      char name[],
+		      char type[],
+		      union label_t *label)
+{
+	sector_t testsect[3];
+	int i, testcount;
+	Sector sect;
+	void *data;
+
+	/* There a three places where we may find a valid label:
+	 * - on an ECKD disk it's block 2
+	 * - on an FBA disk it's block 1
+	 * - on an CMS formatted FBA disk it is sector 1, even if the block size
+	 *   is larger than 512 bytes (possible if the DIAG discipline is used)
+	 * If we have a valid info structure, then we know exactly which case we
+	 * have, otherwise we just search through all possebilities.
+	 */
+	if (info) {
+		if ((info->cu_type == 0x6310 && info->dev_type == 0x9336) ||
+		    (info->cu_type == 0x3880 && info->dev_type == 0x3370))
+			testsect[0] = info->label_block;
+		else
+			testsect[0] = info->label_block * (blocksize >> 9);
+		testcount = 1;
+	} else {
+		testsect[0] = 1;
+		testsect[1] = (blocksize >> 9);
+		testsect[2] = 2 * (blocksize >> 9);
+		testcount = 3;
+	}
+	for (i = 0; i < testcount; ++i) {
+		data = read_part_sector(state, testsect[i], &sect);
+		if (data == NULL)
+			continue;
+		memcpy(label, data, sizeof(*label));
+		memcpy(type, data, DASD_VOL_TYPE_LEN);
+		EBCASC(type, DASD_VOL_TYPE_LEN);
+		put_dev_sector(sect);
+		switch (get_label_by_type(type)) {
+		case DASD_VOLLBL_TYPE_VOL1:
+			memcpy(name, label->vol.volid, DASD_VOL_ID_LEN);
+			EBCASC(name, DASD_VOL_ID_LEN);
+			*labelsect = testsect[i];
+			return 1;
+		case DASD_VOLLBL_TYPE_LNX1:
+		case DASD_VOLLBL_TYPE_CMS1:
+			memcpy(name, label->lnx.volid, DASD_VOL_ID_LEN);
+			EBCASC(name, DASD_VOL_ID_LEN);
+			*labelsect = testsect[i];
+			return 1;
+		default:
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int find_vol1_partitions(struct parsed_partitions *state,
+				struct hd_geometry *geo,
+				int blocksize,
+				char name[],
+				union label_t *label)
+{
+	sector_t blk;
+	int counter;
+	Sector sect;
+	unsigned char *data;
+	loff_t offset, size;
+	struct vtoc_format1_label f1;
+	int secperblk;
+
+	seq_buf_printf(&state->pp_buf, "VOL1/%8s:", name);
+	/*
+	 * get start of VTOC from the disk label and then search for format1
+	 * and format8 labels
+	 */
+	secperblk = blocksize >> 9;
+	blk = cchhb2blk(&label->vol.vtoc, geo) + 1;
+	counter = 0;
+	data = read_part_sector(state, blk * secperblk, &sect);
+	while (data != NULL) {
+		memcpy(&f1, data, sizeof(struct vtoc_format1_label));
+		put_dev_sector(sect);
+		/* skip FMT4 / FMT5 / FMT7 labels */
+		if (f1.DS1FMTID == _ascebc['4']
+		    || f1.DS1FMTID == _ascebc['5']
+		    || f1.DS1FMTID == _ascebc['7']
+		    || f1.DS1FMTID == _ascebc['9']) {
+			blk++;
+			data = read_part_sector(state, blk * secperblk, &sect);
+			continue;
+		}
+		/* only FMT1 and 8 labels valid at this point */
+		if (f1.DS1FMTID != _ascebc['1'] &&
+		    f1.DS1FMTID != _ascebc['8'])
+			break;
+		/* OK, we got valid partition data */
+		offset = cchh2blk(&f1.DS1EXT1.llimit, geo);
+		size  = cchh2blk(&f1.DS1EXT1.ulimit, geo) -
+			offset + geo->sectors;
+		offset *= secperblk;
+		size *= secperblk;
+		if (counter >= state->limit)
+			break;
+		put_partition(state, counter + 1, offset, size);
+		counter++;
+		blk++;
+		data = read_part_sector(state, blk * secperblk, &sect);
+	}
+	seq_buf_puts(&state->pp_buf, "\n");
+
+	if (!data)
+		return -1;
+
+	return 1;
+}
+
+static int find_lnx1_partitions(struct parsed_partitions *state,
+				struct hd_geometry *geo,
+				int blocksize,
+				char name[],
+				union label_t *label,
+				sector_t labelsect,
+				sector_t nr_sectors,
+				dasd_information2_t *info)
+{
+	loff_t offset, geo_size, size;
+	int secperblk;
+
+	seq_buf_printf(&state->pp_buf, "LNX1/%8s:", name);
+	secperblk = blocksize >> 9;
+	if (label->lnx.ldl_version == 0xf2) {
+		size = label->lnx.formatted_blocks * secperblk;
+	} else {
+		/*
+		 * Formated w/o large volume support. If the sanity check
+		 * 'size based on geo == size based on nr_sectors' is true, then
+		 * we can safely assume that we know the formatted size of
+		 * the disk, otherwise we need additional information
+		 * that we can only get from a real DASD device.
+		 */
+		geo_size = geo->cylinders * geo->heads
+			* geo->sectors * secperblk;
+		size = nr_sectors;
+		if (size != geo_size) {
+			if (!info) {
+				seq_buf_puts(&state->pp_buf, "\n");
+				return 1;
+			}
+			if (!strcmp(info->type, "ECKD"))
+				if (geo_size < size)
+					size = geo_size;
+			/* else keep size based on nr_sectors */
+		}
+	}
+	/* first and only partition starts in the first block after the label */
+	offset = labelsect + secperblk;
+	put_partition(state, 1, offset, size - offset);
+	seq_buf_puts(&state->pp_buf, "\n");
+	return 1;
+}
+
+static int find_cms1_partitions(struct parsed_partitions *state,
+				struct hd_geometry *geo,
+				int blocksize,
+				char name[],
+				union label_t *label,
+				sector_t labelsect)
+{
+	loff_t offset, size;
+	int secperblk;
+
+	/*
+	 * VM style CMS1 labeled disk
+	 */
+	blocksize = label->cms.block_size;
+	secperblk = blocksize >> 9;
+	if (label->cms.disk_offset != 0) {
+		seq_buf_printf(&state->pp_buf, "CMS1/%8s(MDSK):", name);
+		/* disk is reserved minidisk */
+		offset = label->cms.disk_offset * secperblk;
+		size = (label->cms.block_count - 1) * secperblk;
+	} else {
+		seq_buf_printf(&state->pp_buf, "CMS1/%8s:", name);
+		/*
+		 * Special case for FBA devices:
+		 * If an FBA device is CMS formatted with blocksize > 512 byte
+		 * and the DIAG discipline is used, then the CMS label is found
+		 * in sector 1 instead of block 1. However, the partition is
+		 * still supposed to start in block 2.
+		 */
+		if (labelsect == 1)
+			offset = 2 * secperblk;
+		else
+			offset = labelsect + secperblk;
+		size = label->cms.block_count * secperblk;
+	}
+
+	put_partition(state, 1, offset, size-offset);
+	seq_buf_puts(&state->pp_buf, "\n");
+	return 1;
+}
+
+
+/*
+ * This is the main function, called by check.c
+ */
+int ibm_partition(struct parsed_partitions *state)
+{
+	int (*fn)(struct gendisk *disk, dasd_information2_t *info);
+	struct gendisk *disk = state->disk;
+	struct block_device *bdev = disk->part0;
+	int blocksize, res;
+	loff_t offset, size;
+	sector_t nr_sectors;
+	dasd_information2_t *info;
+	struct hd_geometry *geo;
+	char type[DASD_VOL_TYPE_LEN + 1] = "";
+	char name[DASD_VOL_ID_LEN + 1] = "";
+	sector_t labelsect;
+	union label_t *label;
+
+	res = 0;
+	if (!disk->fops->getgeo)
+		goto out_exit;
+	fn = symbol_get(dasd_biodasdinfo);
+	blocksize = bdev_logical_block_size(bdev);
+	if (blocksize <= 0)
+		goto out_symbol;
+	nr_sectors = bdev_nr_sectors(bdev);
+	if (nr_sectors == 0)
+		goto out_symbol;
+	info = kmalloc_obj(dasd_information2_t);
+	if (info == NULL)
+		goto out_symbol;
+	geo = kmalloc_obj(struct hd_geometry);
+	if (geo == NULL)
+		goto out_nogeo;
+	label = kmalloc_obj(union label_t);
+	if (label == NULL)
+		goto out_nolab;
+	/* set start if not filled by getgeo function e.g. virtblk */
+	geo->start = get_start_sect(bdev);
+	if (disk->fops->getgeo(disk, geo))
+		goto out_freeall;
+	if (!fn || fn(disk, info)) {
+		kfree(info);
+		info = NULL;
+	}
+
+	if (find_label(state, info, geo, blocksize, &labelsect, name, type, label)) {
+		switch (get_label_by_type(type)) {
+		case DASD_VOLLBL_TYPE_VOL1:
+			res = find_vol1_partitions(state, geo, blocksize, name,
+						   label);
+			break;
+		case DASD_VOLLBL_TYPE_LNX1:
+			res = find_lnx1_partitions(state, geo, blocksize, name,
+						   label, labelsect, nr_sectors,
+						   info);
+			break;
+		case DASD_VOLLBL_TYPE_CMS1:
+			res = find_cms1_partitions(state, geo, blocksize, name,
+						   label, labelsect);
+			break;
+		}
+	} else if (info) {
+		/*
+		 * ugly but needed for backward compatibility:
+		 * If the block device is a DASD (i.e. BIODASDINFO2 works),
+		 * then we claim it in any case, even though it has no valid
+		 * label. If it has the LDL format, then we simply define a
+		 * partition as if it had an LNX1 label.
+		 */
+		res = 1;
+		if (info->format == DASD_FORMAT_LDL) {
+			seq_buf_puts(&state->pp_buf, "(nonl)");
+			size = nr_sectors;
+			offset = (info->label_block + 1) * (blocksize >> 9);
+			put_partition(state, 1, offset, size-offset);
+			seq_buf_puts(&state->pp_buf, "\n");
+		}
+	} else
+		res = 0;
+
+out_freeall:
+	kfree(label);
+out_nolab:
+	kfree(geo);
+out_nogeo:
+	kfree(info);
+out_symbol:
+	if (fn)
+		symbol_put(dasd_biodasdinfo);
+out_exit:
+	return res;
+}