Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 346 insertions, 0 deletions

diff --git a/drivers/char/bsr.c b/drivers/char/bsr.c
new file mode 100644
index 000000000..98e9327bf
--- /dev/null
+++ b/drivers/char/bsr.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* IBM POWER Barrier Synchronization Register Driver
+ *
+ * Copyright IBM Corporation 2008
+ *
+ * Author: Sonny Rao <sonnyrao@us.ibm.com>
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/cdev.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/io.h>
+
+/*
+ This driver exposes a special register which can be used for fast
+ synchronization across a large SMP machine.  The hardware is exposed
+ as an array of bytes where each process will write to one of the bytes to
+ indicate it has finished the current stage and this update is broadcast to
+ all processors without having to bounce a cacheline between them. In
+ POWER5 and POWER6 there is one of these registers per SMP,  but it is
+ presented in two forms; first, it is given as a whole and then as a number
+ of smaller registers which alias to parts of the single whole register.
+ This can potentially allow multiple groups of processes to each have their
+ own private synchronization device.
+
+ Note that this hardware *must* be written to using *only* single byte writes.
+ It may be read using 1, 2, 4, or 8 byte loads which must be aligned since
+ this region is treated as cache-inhibited  processes should also use a
+ full sync before and after writing to the BSR to ensure all stores and
+ the BSR update have made it to all chips in the system
+*/
+
+/* This is arbitrary number, up to Power6 it's been 17 or fewer  */
+#define BSR_MAX_DEVS (32)
+
+struct bsr_dev {
+	u64      bsr_addr;     /* Real address */
+	u64      bsr_len;      /* length of mem region we can map */
+	unsigned bsr_bytes;    /* size of the BSR reg itself */
+	unsigned bsr_stride;   /* interval at which BSR repeats in the page */
+	unsigned bsr_type;     /* maps to enum below */
+	unsigned bsr_num;      /* bsr id number for its type */
+	int      bsr_minor;
+
+	struct list_head bsr_list;
+
+	dev_t    bsr_dev;
+	struct cdev bsr_cdev;
+	struct device *bsr_device;
+	char     bsr_name[32];
+
+};
+
+static unsigned total_bsr_devs;
+static LIST_HEAD(bsr_devs);
+static int bsr_major;
+
+enum {
+	BSR_8    = 0,
+	BSR_16   = 1,
+	BSR_64   = 2,
+	BSR_128  = 3,
+	BSR_4096 = 4,
+	BSR_UNKNOWN = 5,
+	BSR_MAX  = 6,
+};
+
+static unsigned bsr_types[BSR_MAX];
+
+static ssize_t
+bsr_size_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
+	return sprintf(buf, "%u\n", bsr_dev->bsr_bytes);
+}
+static DEVICE_ATTR_RO(bsr_size);
+
+static ssize_t
+bsr_stride_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
+	return sprintf(buf, "%u\n", bsr_dev->bsr_stride);
+}
+static DEVICE_ATTR_RO(bsr_stride);
+
+static ssize_t
+bsr_length_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
+	return sprintf(buf, "%llu\n", bsr_dev->bsr_len);
+}
+static DEVICE_ATTR_RO(bsr_length);
+
+static struct attribute *bsr_dev_attrs[] = {
+	&dev_attr_bsr_size.attr,
+	&dev_attr_bsr_stride.attr,
+	&dev_attr_bsr_length.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(bsr_dev);
+
+static const struct class bsr_class = {
+	.name		= "bsr",
+	.dev_groups	= bsr_dev_groups,
+};
+
+static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	unsigned long size   = vma->vm_end - vma->vm_start;
+	struct bsr_dev *dev = filp->private_data;
+	int ret;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	/* check for the case of a small BSR device and map one 4k page for it*/
+	if (dev->bsr_len < PAGE_SIZE && size == PAGE_SIZE)
+		ret = remap_4k_pfn(vma, vma->vm_start, dev->bsr_addr >> 12,
+				   vma->vm_page_prot);
+	else if (size <= dev->bsr_len)
+		ret = io_remap_pfn_range(vma, vma->vm_start,
+					 dev->bsr_addr >> PAGE_SHIFT,
+					 size, vma->vm_page_prot);
+	else
+		return -EINVAL;
+
+	if (ret)
+		return -EAGAIN;
+
+	return 0;
+}
+
+static int bsr_open(struct inode *inode, struct file *filp)
+{
+	struct cdev *cdev = inode->i_cdev;
+	struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev);
+
+	filp->private_data = dev;
+	return 0;
+}
+
+static const struct file_operations bsr_fops = {
+	.owner = THIS_MODULE,
+	.mmap  = bsr_mmap,
+	.open  = bsr_open,
+	.llseek = noop_llseek,
+};
+
+static void bsr_cleanup_devs(void)
+{
+	struct bsr_dev *cur, *n;
+
+	list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) {
+		if (cur->bsr_device) {
+			cdev_del(&cur->bsr_cdev);
+			device_del(cur->bsr_device);
+		}
+		list_del(&cur->bsr_list);
+		kfree(cur);
+	}
+}
+
+static int bsr_add_node(struct device_node *bn)
+{
+	int bsr_stride_len, bsr_bytes_len, num_bsr_devs;
+	const u32 *bsr_stride;
+	const u32 *bsr_bytes;
+	unsigned i;
+	int ret = -ENODEV;
+
+	bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
+	bsr_bytes  = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);
+
+	if (!bsr_stride || !bsr_bytes ||
+	    (bsr_stride_len != bsr_bytes_len)) {
+		printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
+		return ret;
+	}
+
+	num_bsr_devs = bsr_bytes_len / sizeof(u32);
+
+	for (i = 0 ; i < num_bsr_devs; i++) {
+		struct bsr_dev *cur = kzalloc_obj(struct bsr_dev);
+		struct resource res;
+		int result;
+
+		if (!cur) {
+			printk(KERN_ERR "Unable to alloc bsr dev\n");
+			ret = -ENOMEM;
+			goto out_err;
+		}
+
+		result = of_address_to_resource(bn, i, &res);
+		if (result < 0) {
+			printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n");
+			kfree(cur);
+			continue;
+		}
+
+		cur->bsr_minor  = i + total_bsr_devs;
+		cur->bsr_addr   = res.start;
+		cur->bsr_len    = resource_size(&res);
+		cur->bsr_bytes  = bsr_bytes[i];
+		cur->bsr_stride = bsr_stride[i];
+		cur->bsr_dev    = MKDEV(bsr_major, i + total_bsr_devs);
+
+		/* if we have a bsr_len of > 4k and less then PAGE_SIZE (64k pages) */
+		/* we can only map 4k of it, so only advertise the 4k in sysfs */
+		if (cur->bsr_len > 4096 && cur->bsr_len < PAGE_SIZE)
+			cur->bsr_len = 4096;
+
+		switch(cur->bsr_bytes) {
+		case 8:
+			cur->bsr_type = BSR_8;
+			break;
+		case 16:
+			cur->bsr_type = BSR_16;
+			break;
+		case 64:
+			cur->bsr_type = BSR_64;
+			break;
+		case 128:
+			cur->bsr_type = BSR_128;
+			break;
+		case 4096:
+			cur->bsr_type = BSR_4096;
+			break;
+		default:
+			cur->bsr_type = BSR_UNKNOWN;
+		}
+
+		cur->bsr_num = bsr_types[cur->bsr_type];
+		snprintf(cur->bsr_name, 32, "bsr%d_%d",
+			 cur->bsr_bytes, cur->bsr_num);
+
+		cdev_init(&cur->bsr_cdev, &bsr_fops);
+		result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
+		if (result) {
+			kfree(cur);
+			goto out_err;
+		}
+
+		cur->bsr_device = device_create(&bsr_class, NULL, cur->bsr_dev,
+						cur, "%s", cur->bsr_name);
+		if (IS_ERR(cur->bsr_device)) {
+			printk(KERN_ERR "device_create failed for %s\n",
+			       cur->bsr_name);
+			cdev_del(&cur->bsr_cdev);
+			kfree(cur);
+			goto out_err;
+		}
+
+		bsr_types[cur->bsr_type] = cur->bsr_num + 1;
+		list_add_tail(&cur->bsr_list, &bsr_devs);
+	}
+
+	total_bsr_devs += num_bsr_devs;
+
+	return 0;
+
+ out_err:
+
+	bsr_cleanup_devs();
+	return ret;
+}
+
+static int bsr_create_devs(struct device_node *bn)
+{
+	int ret;
+
+	while (bn) {
+		ret = bsr_add_node(bn);
+		if (ret) {
+			of_node_put(bn);
+			return ret;
+		}
+		bn = of_find_compatible_node(bn, NULL, "ibm,bsr");
+	}
+	return 0;
+}
+
+static int __init bsr_init(void)
+{
+	struct device_node *np;
+	dev_t bsr_dev;
+	int ret = -ENODEV;
+
+	np = of_find_compatible_node(NULL, NULL, "ibm,bsr");
+	if (!np)
+		goto out_err;
+
+	ret = class_register(&bsr_class);
+	if (ret)
+		goto out_err_1;
+
+	ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
+	bsr_major = MAJOR(bsr_dev);
+	if (ret < 0) {
+		printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n");
+		goto out_err_2;
+	}
+
+	ret = bsr_create_devs(np);
+	if (ret < 0) {
+		np = NULL;
+		goto out_err_3;
+	}
+
+	return 0;
+
+ out_err_3:
+	unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);
+
+ out_err_2:
+	class_unregister(&bsr_class);
+
+ out_err_1:
+	of_node_put(np);
+
+ out_err:
+
+	return ret;
+}
+
+static void __exit  bsr_exit(void)
+{
+
+	bsr_cleanup_devs();
+
+	class_unregister(&bsr_class);
+
+	if (bsr_major)
+		unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
+}
+
+module_init(bsr_init);
+module_exit(bsr_exit);
+MODULE_DESCRIPTION("IBM POWER Barrier Synchronization Register Driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sonny Rao <sonnyrao@us.ibm.com>");