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, 274 insertions, 0 deletions

diff --git a/drivers/media/rc/rc-loopback.c b/drivers/media/rc/rc-loopback.c
new file mode 100644
index 000000000..53d054071
--- /dev/null
+++ b/drivers/media/rc/rc-loopback.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Loopback driver for rc-core,
+ *
+ * Copyright (c) 2010 David Härdeman <david@hardeman.nu>
+ *
+ * This driver receives TX data and passes it back as RX data,
+ * which is useful for (scripted) debugging of rc-core without
+ * having to use actual hardware.
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <media/rc-core.h>
+
+#define DRIVER_NAME		"rc-loopback"
+#define RXMASK_NARROWBAND	0x1
+#define RXMASK_WIDEBAND		0x2
+
+struct loopback_dev {
+	struct rc_dev *dev;
+	u32 txmask;
+	u32 txcarrier;
+	u32 txduty;
+	bool idle;
+	bool wideband;
+	bool carrierreport;
+	u32 rxcarriermin;
+	u32 rxcarriermax;
+};
+
+static struct loopback_dev loopdev;
+
+static int loop_set_tx_mask(struct rc_dev *dev, u32 mask)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	if ((mask & (RXMASK_NARROWBAND | RXMASK_WIDEBAND)) != mask) {
+		dev_dbg(&dev->dev, "invalid tx mask: %u\n", mask);
+		return 2;
+	}
+
+	dev_dbg(&dev->dev, "setting tx mask: %u\n", mask);
+	lodev->txmask = mask;
+	return 0;
+}
+
+static int loop_set_tx_carrier(struct rc_dev *dev, u32 carrier)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	dev_dbg(&dev->dev, "setting tx carrier: %u\n", carrier);
+	lodev->txcarrier = carrier;
+	return 0;
+}
+
+static int loop_set_tx_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	if (duty_cycle < 1 || duty_cycle > 99) {
+		dev_dbg(&dev->dev, "invalid duty cycle: %u\n", duty_cycle);
+		return -EINVAL;
+	}
+
+	dev_dbg(&dev->dev, "setting duty cycle: %u\n", duty_cycle);
+	lodev->txduty = duty_cycle;
+	return 0;
+}
+
+static int loop_set_rx_carrier_range(struct rc_dev *dev, u32 min, u32 max)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	if (min < 1 || min > max) {
+		dev_dbg(&dev->dev, "invalid rx carrier range %u to %u\n", min, max);
+		return -EINVAL;
+	}
+
+	dev_dbg(&dev->dev, "setting rx carrier range %u to %u\n", min, max);
+	lodev->rxcarriermin = min;
+	lodev->rxcarriermax = max;
+	return 0;
+}
+
+static int loop_tx_ir(struct rc_dev *dev, unsigned *txbuf, unsigned count)
+{
+	struct loopback_dev *lodev = dev->priv;
+	u32 rxmask;
+	unsigned i;
+	struct ir_raw_event rawir = {};
+
+	if (lodev->txcarrier < lodev->rxcarriermin ||
+	    lodev->txcarrier > lodev->rxcarriermax) {
+		dev_dbg(&dev->dev, "ignoring tx, carrier out of range\n");
+		goto out;
+	}
+
+	if (lodev->wideband)
+		rxmask = RXMASK_WIDEBAND;
+	else
+		rxmask = RXMASK_NARROWBAND;
+
+	if (!(rxmask & lodev->txmask)) {
+		dev_dbg(&dev->dev, "ignoring tx, rx mask mismatch\n");
+		goto out;
+	}
+
+	for (i = 0; i < count; i++) {
+		rawir.pulse = i % 2 ? false : true;
+		rawir.duration = txbuf[i];
+
+		/* simulate overflow if ridiculously long pulse was sent */
+		if (rawir.pulse && rawir.duration > MS_TO_US(50))
+			ir_raw_event_overflow(dev);
+		else
+			ir_raw_event_store_with_filter(dev, &rawir);
+	}
+
+	if (lodev->carrierreport) {
+		rawir.pulse = false;
+		rawir.carrier_report = true;
+		rawir.carrier = lodev->txcarrier;
+
+		ir_raw_event_store(dev, &rawir);
+	}
+
+	/* Fake a silence long enough to cause us to go idle */
+	rawir.pulse = false;
+	rawir.duration = dev->timeout;
+	ir_raw_event_store_with_filter(dev, &rawir);
+
+	ir_raw_event_handle(dev);
+
+out:
+	return count;
+}
+
+static void loop_set_idle(struct rc_dev *dev, bool enable)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	if (lodev->idle != enable) {
+		dev_dbg(&dev->dev, "%sing idle mode\n", enable ? "enter" : "exit");
+		lodev->idle = enable;
+	}
+}
+
+static int loop_set_wideband_receiver(struct rc_dev *dev, int enable)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	if (lodev->wideband != enable) {
+		dev_dbg(&dev->dev, "using %sband receiver\n", enable ? "wide" : "narrow");
+		lodev->wideband = !!enable;
+	}
+
+	return 0;
+}
+
+static int loop_set_carrier_report(struct rc_dev *dev, int enable)
+{
+	struct loopback_dev *lodev = dev->priv;
+
+	if (lodev->carrierreport != enable) {
+		dev_dbg(&dev->dev, "%sabling carrier reports\n", enable ? "en" : "dis");
+		lodev->carrierreport = !!enable;
+	}
+
+	return 0;
+}
+
+static int loop_set_wakeup_filter(struct rc_dev *dev,
+				  struct rc_scancode_filter *sc)
+{
+	static const unsigned int max = 512;
+	struct ir_raw_event *raw;
+	int ret;
+	int i;
+
+	/* fine to disable filter */
+	if (!sc->mask)
+		return 0;
+
+	/* encode the specified filter and loop it back */
+	raw = kmalloc_objs(*raw, max);
+	if (!raw)
+		return -ENOMEM;
+
+	ret = ir_raw_encode_scancode(dev->wakeup_protocol, sc->data, raw, max);
+	/* still loop back the partial raw IR even if it's incomplete */
+	if (ret == -ENOBUFS)
+		ret = max;
+	if (ret >= 0) {
+		/* do the loopback */
+		for (i = 0; i < ret; ++i)
+			ir_raw_event_store(dev, &raw[i]);
+		ir_raw_event_handle(dev);
+
+		ret = 0;
+	}
+
+	kfree(raw);
+
+	return ret;
+}
+
+static int __init loop_init(void)
+{
+	struct rc_dev *rc;
+	int ret;
+
+	rc = rc_allocate_device(RC_DRIVER_IR_RAW);
+	if (!rc)
+		return -ENOMEM;
+
+	rc->device_name		= "rc-core loopback device";
+	rc->input_phys		= "rc-core/virtual";
+	rc->input_id.bustype	= BUS_VIRTUAL;
+	rc->input_id.version	= 1;
+	rc->driver_name		= DRIVER_NAME;
+	rc->map_name		= RC_MAP_EMPTY;
+	rc->priv		= &loopdev;
+	rc->allowed_protocols	= RC_PROTO_BIT_ALL_IR_DECODER;
+	rc->allowed_wakeup_protocols = RC_PROTO_BIT_ALL_IR_ENCODER;
+	rc->encode_wakeup	= true;
+	rc->timeout		= IR_DEFAULT_TIMEOUT;
+	rc->min_timeout		= 1;
+	rc->max_timeout		= IR_MAX_TIMEOUT;
+	rc->rx_resolution	= 1;
+	rc->s_tx_mask		= loop_set_tx_mask;
+	rc->s_tx_carrier	= loop_set_tx_carrier;
+	rc->s_tx_duty_cycle	= loop_set_tx_duty_cycle;
+	rc->s_rx_carrier_range	= loop_set_rx_carrier_range;
+	rc->tx_ir		= loop_tx_ir;
+	rc->s_idle		= loop_set_idle;
+	rc->s_wideband_receiver	= loop_set_wideband_receiver;
+	rc->s_carrier_report	= loop_set_carrier_report;
+	rc->s_wakeup_filter	= loop_set_wakeup_filter;
+
+	loopdev.txmask		= RXMASK_NARROWBAND;
+	loopdev.txcarrier	= 36000;
+	loopdev.txduty		= 50;
+	loopdev.rxcarriermin	= 1;
+	loopdev.rxcarriermax	= ~0;
+	loopdev.idle		= true;
+	loopdev.wideband	= false;
+	loopdev.carrierreport	= false;
+
+	ret = rc_register_device(rc);
+	if (ret < 0) {
+		dev_err(&rc->dev, "rc_dev registration failed\n");
+		rc_free_device(rc);
+		return ret;
+	}
+
+	loopdev.dev = rc;
+	return 0;
+}
+
+static void __exit loop_exit(void)
+{
+	rc_unregister_device(loopdev.dev);
+	rc_free_device(loopdev.dev);
+}
+
+module_init(loop_init);
+module_exit(loop_exit);
+
+MODULE_DESCRIPTION("Loopback device for rc-core debugging");
+MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
+MODULE_LICENSE("GPL");