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, 283 insertions, 0 deletions

diff --git a/drivers/mfd/janz-cmodio.c b/drivers/mfd/janz-cmodio.c
new file mode 100644
index 000000000..add3bc041
--- /dev/null
+++ b/drivers/mfd/janz-cmodio.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Janz CMOD-IO MODULbus Carrier Board PCI Driver
+ *
+ * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
+ *
+ * Lots of inspiration and code was copied from drivers/mfd/sm501.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mfd/core.h>
+
+#include <linux/mfd/janz.h>
+
+#define DRV_NAME "janz-cmodio"
+
+/* Size of each MODULbus module in PCI BAR4 */
+#define CMODIO_MODULBUS_SIZE	0x200
+
+/* Maximum number of MODULbus modules on a CMOD-IO carrier board */
+#define CMODIO_MAX_MODULES	4
+
+/* Module Parameters */
+static unsigned int num_modules = CMODIO_MAX_MODULES;
+static char *modules[CMODIO_MAX_MODULES] = {
+	"empty", "empty", "empty", "empty",
+};
+
+module_param_array(modules, charp, &num_modules, S_IRUGO);
+MODULE_PARM_DESC(modules, "MODULbus modules attached to the carrier board");
+
+/* Unique Device Id */
+static unsigned int cmodio_id;
+
+struct cmodio_device {
+	/* Parent PCI device */
+	struct pci_dev *pdev;
+
+	/* PLX control registers */
+	struct janz_cmodio_onboard_regs __iomem *ctrl;
+
+	/* hex switch position */
+	u8 hex;
+
+	/* mfd-core API */
+	struct mfd_cell cells[CMODIO_MAX_MODULES];
+	struct resource resources[3 * CMODIO_MAX_MODULES];
+	struct janz_platform_data pdata[CMODIO_MAX_MODULES];
+};
+
+/*
+ * Subdevices using the mfd-core API
+ */
+
+static int cmodio_setup_subdevice(struct cmodio_device *priv,
+					    char *name, unsigned int devno,
+					    unsigned int modno)
+{
+	struct janz_platform_data *pdata;
+	struct mfd_cell *cell;
+	struct resource *res;
+	struct pci_dev *pci;
+
+	pci = priv->pdev;
+	cell = &priv->cells[devno];
+	res = &priv->resources[devno * 3];
+	pdata = &priv->pdata[devno];
+
+	cell->name = name;
+	cell->resources = res;
+	cell->num_resources = 3;
+
+	/* Setup the subdevice ID -- must be unique */
+	cell->id = cmodio_id++;
+
+	/* Add platform data */
+	pdata->modno = modno;
+	cell->platform_data = pdata;
+	cell->pdata_size = sizeof(*pdata);
+
+	/* MODULbus registers -- PCI BAR3 is big-endian MODULbus access */
+	res->flags = IORESOURCE_MEM;
+	res->parent = &pci->resource[3];
+	res->start = pci->resource[3].start + (CMODIO_MODULBUS_SIZE * modno);
+	res->end = res->start + CMODIO_MODULBUS_SIZE - 1;
+	res++;
+
+	/* PLX Control Registers -- PCI BAR4 is interrupt and other registers */
+	res->flags = IORESOURCE_MEM;
+	res->parent = &pci->resource[4];
+	res->start = pci->resource[4].start;
+	res->end = pci->resource[4].end;
+	res++;
+
+	/*
+	 * IRQ
+	 *
+	 * The start and end fields are used as an offset to the irq_base
+	 * parameter passed into the mfd_add_devices() function call. All
+	 * devices share the same IRQ.
+	 */
+	res->flags = IORESOURCE_IRQ;
+	res->parent = NULL;
+	res->start = 0;
+	res->end = 0;
+	res++;
+
+	return 0;
+}
+
+/* Probe each submodule using kernel parameters */
+static int cmodio_probe_submodules(struct cmodio_device *priv)
+{
+	struct pci_dev *pdev = priv->pdev;
+	unsigned int num_probed = 0;
+	char *name;
+	int i;
+
+	for (i = 0; i < num_modules; i++) {
+		name = modules[i];
+		if (!strcmp(name, "") || !strcmp(name, "empty"))
+			continue;
+
+		dev_dbg(&priv->pdev->dev, "MODULbus %d: name %s\n", i, name);
+		cmodio_setup_subdevice(priv, name, num_probed, i);
+		num_probed++;
+	}
+
+	/* print an error message if no modules were probed */
+	if (num_probed == 0) {
+		dev_err(&priv->pdev->dev, "no MODULbus modules specified, "
+					  "please set the ``modules'' kernel "
+					  "parameter according to your "
+					  "hardware configuration\n");
+		return -ENODEV;
+	}
+
+	return mfd_add_devices(&pdev->dev, 0, priv->cells,
+			       num_probed, NULL, pdev->irq, NULL);
+}
+
+/*
+ * SYSFS Attributes
+ */
+
+static ssize_t modulbus_number_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct cmodio_device *priv = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%x\n", priv->hex);
+}
+
+static DEVICE_ATTR_RO(modulbus_number);
+
+static struct attribute *cmodio_sysfs_attrs[] = {
+	&dev_attr_modulbus_number.attr,
+	NULL,
+};
+
+static const struct attribute_group cmodio_sysfs_attr_group = {
+	.attrs = cmodio_sysfs_attrs,
+};
+
+/*
+ * PCI Driver
+ */
+
+static int cmodio_pci_probe(struct pci_dev *dev,
+				      const struct pci_device_id *id)
+{
+	struct cmodio_device *priv;
+	int ret;
+
+	priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	pci_set_drvdata(dev, priv);
+	priv->pdev = dev;
+
+	/* Hardware Initialization */
+	ret = pci_enable_device(dev);
+	if (ret) {
+		dev_err(&dev->dev, "unable to enable device\n");
+		return ret;
+	}
+
+	pci_set_master(dev);
+	ret = pci_request_regions(dev, DRV_NAME);
+	if (ret) {
+		dev_err(&dev->dev, "unable to request regions\n");
+		goto out_pci_disable_device;
+	}
+
+	/* Onboard configuration registers */
+	priv->ctrl = pci_ioremap_bar(dev, 4);
+	if (!priv->ctrl) {
+		dev_err(&dev->dev, "unable to remap onboard regs\n");
+		ret = -ENOMEM;
+		goto out_pci_release_regions;
+	}
+
+	/* Read the hex switch on the carrier board */
+	priv->hex = ioread8(&priv->ctrl->int_enable);
+
+	/* Add the MODULbus number (hex switch value) to the device's sysfs */
+	ret = sysfs_create_group(&dev->dev.kobj, &cmodio_sysfs_attr_group);
+	if (ret) {
+		dev_err(&dev->dev, "unable to create sysfs attributes\n");
+		goto out_unmap_ctrl;
+	}
+
+	/*
+	 * Disable all interrupt lines, each submodule will enable its
+	 * own interrupt line if needed
+	 */
+	iowrite8(0xf, &priv->ctrl->int_disable);
+
+	/* Register drivers for all submodules */
+	ret = cmodio_probe_submodules(priv);
+	if (ret) {
+		dev_err(&dev->dev, "unable to probe submodules\n");
+		goto out_sysfs_remove_group;
+	}
+
+	return 0;
+
+out_sysfs_remove_group:
+	sysfs_remove_group(&dev->dev.kobj, &cmodio_sysfs_attr_group);
+out_unmap_ctrl:
+	iounmap(priv->ctrl);
+out_pci_release_regions:
+	pci_release_regions(dev);
+out_pci_disable_device:
+	pci_disable_device(dev);
+
+	return ret;
+}
+
+static void cmodio_pci_remove(struct pci_dev *dev)
+{
+	struct cmodio_device *priv = pci_get_drvdata(dev);
+
+	mfd_remove_devices(&dev->dev);
+	sysfs_remove_group(&dev->dev.kobj, &cmodio_sysfs_attr_group);
+	iounmap(priv->ctrl);
+	pci_release_regions(dev);
+	pci_disable_device(dev);
+}
+
+#define PCI_VENDOR_ID_JANZ		0x13c3
+
+/* The list of devices that this module will support */
+static const struct pci_device_id cmodio_pci_ids[] = {
+	{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030, PCI_VENDOR_ID_JANZ, 0x0101 },
+	{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9050, PCI_VENDOR_ID_JANZ, 0x0100 },
+	{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030, PCI_VENDOR_ID_JANZ, 0x0201 },
+	{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030, PCI_VENDOR_ID_JANZ, 0x0202 },
+	{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9050, PCI_VENDOR_ID_JANZ, 0x0201 },
+	{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9050, PCI_VENDOR_ID_JANZ, 0x0202 },
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(pci, cmodio_pci_ids);
+
+static struct pci_driver cmodio_pci_driver = {
+	.name     = DRV_NAME,
+	.id_table = cmodio_pci_ids,
+	.probe    = cmodio_pci_probe,
+	.remove   = cmodio_pci_remove,
+};
+
+module_pci_driver(cmodio_pci_driver);
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("Janz CMOD-IO PCI MODULbus Carrier Board Driver");
+MODULE_LICENSE("GPL");