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, 235 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-max6900.c b/drivers/rtc/rtc-max6900.c
new file mode 100644
index 000000000..8ef6d0fcd
--- /dev/null
+++ b/drivers/rtc/rtc-max6900.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rtc class driver for the Maxim MAX6900 chip
+ *
+ * Copyright (c) 2007 MontaVista, Software, Inc.
+ *
+ * Author: Dale Farnsworth <dale@farnsworth.org>
+ *
+ * based on previously existing rtc class drivers
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/delay.h>
+
+/*
+ * register indices
+ */
+#define MAX6900_REG_SC			0	/* seconds      00-59 */
+#define MAX6900_REG_MN			1	/* minutes      00-59 */
+#define MAX6900_REG_HR			2	/* hours        00-23 */
+#define MAX6900_REG_DT			3	/* day of month 00-31 */
+#define MAX6900_REG_MO			4	/* month        01-12 */
+#define MAX6900_REG_DW			5	/* day of week   1-7  */
+#define MAX6900_REG_YR			6	/* year         00-99 */
+#define MAX6900_REG_CT			7	/* control */
+						/* register 8 is undocumented */
+#define MAX6900_REG_CENTURY		9	/* century */
+#define MAX6900_REG_LEN			10
+
+#define MAX6900_BURST_LEN		8	/* can burst r/w first 8 regs */
+
+#define MAX6900_REG_CT_WP		(1 << 7)	/* Write Protect */
+
+/*
+ * register read/write commands
+ */
+#define MAX6900_REG_CONTROL_WRITE	0x8e
+#define MAX6900_REG_CENTURY_WRITE	0x92
+#define MAX6900_REG_CENTURY_READ	0x93
+#define MAX6900_REG_RESERVED_READ	0x96
+#define MAX6900_REG_BURST_WRITE		0xbe
+#define MAX6900_REG_BURST_READ		0xbf
+
+#define MAX6900_IDLE_TIME_AFTER_WRITE	3	/* specification says 2.5 mS */
+
+static struct i2c_driver max6900_driver;
+
+static int max6900_i2c_read_regs(struct i2c_client *client, u8 *buf)
+{
+	u8 reg_burst_read[1] = { MAX6900_REG_BURST_READ };
+	u8 reg_century_read[1] = { MAX6900_REG_CENTURY_READ };
+	struct i2c_msg msgs[4] = {
+		{
+		 .addr = client->addr,
+		 .flags = 0,	/* write */
+		 .len = sizeof(reg_burst_read),
+		 .buf = reg_burst_read}
+		,
+		{
+		 .addr = client->addr,
+		 .flags = I2C_M_RD,
+		 .len = MAX6900_BURST_LEN,
+		 .buf = buf}
+		,
+		{
+		 .addr = client->addr,
+		 .flags = 0,	/* write */
+		 .len = sizeof(reg_century_read),
+		 .buf = reg_century_read}
+		,
+		{
+		 .addr = client->addr,
+		 .flags = I2C_M_RD,
+		 .len = sizeof(buf[MAX6900_REG_CENTURY]),
+		 .buf = &buf[MAX6900_REG_CENTURY]
+		 }
+	};
+	int rc;
+
+	rc = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (rc != ARRAY_SIZE(msgs)) {
+		dev_err(&client->dev, "%s: register read failed\n", __func__);
+		return -EIO;
+	}
+	return 0;
+}
+
+static int max6900_i2c_write_regs(struct i2c_client *client, u8 const *buf)
+{
+	u8 i2c_century_buf[1 + 1] = { MAX6900_REG_CENTURY_WRITE };
+	struct i2c_msg century_msgs[1] = {
+		{
+		 .addr = client->addr,
+		 .flags = 0,	/* write */
+		 .len = sizeof(i2c_century_buf),
+		 .buf = i2c_century_buf}
+	};
+	u8 i2c_burst_buf[MAX6900_BURST_LEN + 1] = { MAX6900_REG_BURST_WRITE };
+	struct i2c_msg burst_msgs[1] = {
+		{
+		 .addr = client->addr,
+		 .flags = 0,	/* write */
+		 .len = sizeof(i2c_burst_buf),
+		 .buf = i2c_burst_buf}
+	};
+	int rc;
+
+	/*
+	 * We have to make separate calls to i2c_transfer because of
+	 * the need to delay after each write to the chip.  Also,
+	 * we write the century byte first, since we set the write-protect
+	 * bit as part of the burst write.
+	 */
+	i2c_century_buf[1] = buf[MAX6900_REG_CENTURY];
+
+	rc = i2c_transfer(client->adapter, century_msgs,
+			  ARRAY_SIZE(century_msgs));
+	if (rc != ARRAY_SIZE(century_msgs))
+		goto write_failed;
+
+	msleep(MAX6900_IDLE_TIME_AFTER_WRITE);
+
+	memcpy(&i2c_burst_buf[1], buf, MAX6900_BURST_LEN);
+
+	rc = i2c_transfer(client->adapter, burst_msgs, ARRAY_SIZE(burst_msgs));
+	if (rc != ARRAY_SIZE(burst_msgs))
+		goto write_failed;
+	msleep(MAX6900_IDLE_TIME_AFTER_WRITE);
+
+	return 0;
+
+ write_failed:
+	dev_err(&client->dev, "%s: register write failed\n", __func__);
+	return -EIO;
+}
+
+static int max6900_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int rc;
+	u8 regs[MAX6900_REG_LEN];
+
+	rc = max6900_i2c_read_regs(client, regs);
+	if (rc < 0)
+		return rc;
+
+	tm->tm_sec = bcd2bin(regs[MAX6900_REG_SC]);
+	tm->tm_min = bcd2bin(regs[MAX6900_REG_MN]);
+	tm->tm_hour = bcd2bin(regs[MAX6900_REG_HR] & 0x3f);
+	tm->tm_mday = bcd2bin(regs[MAX6900_REG_DT]);
+	tm->tm_mon = bcd2bin(regs[MAX6900_REG_MO]) - 1;
+	tm->tm_year = bcd2bin(regs[MAX6900_REG_YR]) +
+		      bcd2bin(regs[MAX6900_REG_CENTURY]) * 100 - 1900;
+	tm->tm_wday = bcd2bin(regs[MAX6900_REG_DW]);
+
+	return 0;
+}
+
+static int max6900_i2c_clear_write_protect(struct i2c_client *client)
+{
+	return i2c_smbus_write_byte_data(client, MAX6900_REG_CONTROL_WRITE, 0);
+}
+
+static int max6900_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	u8 regs[MAX6900_REG_LEN];
+	int rc;
+
+	rc = max6900_i2c_clear_write_protect(client);
+	if (rc < 0)
+		return rc;
+
+	regs[MAX6900_REG_SC] = bin2bcd(tm->tm_sec);
+	regs[MAX6900_REG_MN] = bin2bcd(tm->tm_min);
+	regs[MAX6900_REG_HR] = bin2bcd(tm->tm_hour);
+	regs[MAX6900_REG_DT] = bin2bcd(tm->tm_mday);
+	regs[MAX6900_REG_MO] = bin2bcd(tm->tm_mon + 1);
+	regs[MAX6900_REG_DW] = bin2bcd(tm->tm_wday);
+	regs[MAX6900_REG_YR] = bin2bcd(tm->tm_year % 100);
+	regs[MAX6900_REG_CENTURY] = bin2bcd((tm->tm_year + 1900) / 100);
+	/* set write protect */
+	regs[MAX6900_REG_CT] = MAX6900_REG_CT_WP;
+
+	rc = max6900_i2c_write_regs(client, regs);
+	if (rc < 0)
+		return rc;
+
+	return 0;
+}
+
+static const struct rtc_class_ops max6900_rtc_ops = {
+	.read_time = max6900_rtc_read_time,
+	.set_time = max6900_rtc_set_time,
+};
+
+static int max6900_probe(struct i2c_client *client)
+{
+	struct rtc_device *rtc;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENODEV;
+
+	rtc = devm_rtc_device_register(&client->dev, max6900_driver.driver.name,
+					&max6900_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	i2c_set_clientdata(client, rtc);
+
+	return 0;
+}
+
+static const struct i2c_device_id max6900_id[] = {
+	{ .name = "max6900" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max6900_id);
+
+static struct i2c_driver max6900_driver = {
+	.driver = {
+		   .name = "rtc-max6900",
+		   },
+	.probe = max6900_probe,
+	.id_table = max6900_id,
+};
+
+module_i2c_driver(max6900_driver);
+
+MODULE_DESCRIPTION("Maxim MAX6900 RTC driver");
+MODULE_AUTHOR("Dale Farnsworth <dale@farnsworth.org>");
+MODULE_LICENSE("GPL");