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, 478 insertions, 0 deletions

diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
new file mode 100644
index 000000000..dc6d0091d
--- /dev/null
+++ b/drivers/acpi/acpi_pad.c
@@ -0,0 +1,478 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * acpi_pad.c ACPI Processor Aggregator Driver
+ *
+ * Copyright (c) 2009, Intel Corporation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpumask.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kthread.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/tick.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/perf_event.h>
+#include <linux/platform_device.h>
+#include <asm/cpuid/api.h>
+#include <asm/mwait.h>
+#include <xen/xen.h>
+
+#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
+
+#define ACPI_PROCESSOR_AGGREGATOR_STATUS_SUCCESS	0
+#define ACPI_PROCESSOR_AGGREGATOR_STATUS_NO_ACTION	1
+
+static DEFINE_MUTEX(isolated_cpus_lock);
+static DEFINE_MUTEX(round_robin_lock);
+
+static bool acpi_pad_teardown;
+
+static unsigned int power_saving_mwait_eax;
+
+static unsigned char tsc_detected_unstable;
+static unsigned char tsc_marked_unstable;
+
+static void power_saving_mwait_init(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+	unsigned int highest_cstate = 0;
+	unsigned int highest_subcstate = 0;
+	int i;
+
+	if (!boot_cpu_has(X86_FEATURE_MWAIT))
+		return;
+
+	cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &edx);
+
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
+		return;
+
+	edx >>= MWAIT_SUBSTATE_SIZE;
+	for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
+		if (edx & MWAIT_SUBSTATE_MASK) {
+			highest_cstate = i;
+			highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
+		}
+	}
+	power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
+		(highest_subcstate - 1);
+
+#if defined(CONFIG_X86)
+	switch (boot_cpu_data.x86_vendor) {
+	case X86_VENDOR_HYGON:
+	case X86_VENDOR_AMD:
+	case X86_VENDOR_INTEL:
+	case X86_VENDOR_ZHAOXIN:
+	case X86_VENDOR_CENTAUR:
+		/*
+		 * AMD Fam10h TSC will tick in all
+		 * C/P/S0/S1 states when this bit is set.
+		 */
+		if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+			tsc_detected_unstable = 1;
+		break;
+	default:
+		/* TSC could halt in idle */
+		tsc_detected_unstable = 1;
+	}
+#endif
+}
+
+static unsigned long cpu_weight[NR_CPUS];
+static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
+static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
+static void round_robin_cpu(unsigned int tsk_index)
+{
+	struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
+	cpumask_var_t tmp;
+	int cpu;
+	unsigned long min_weight = -1;
+	unsigned long preferred_cpu;
+
+	if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
+		return;
+
+	mutex_lock(&round_robin_lock);
+	cpumask_clear(tmp);
+	for_each_cpu(cpu, pad_busy_cpus)
+		cpumask_or(tmp, tmp, topology_sibling_cpumask(cpu));
+	cpumask_andnot(tmp, cpu_online_mask, tmp);
+	/* avoid HT siblings if possible */
+	if (cpumask_empty(tmp))
+		cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
+	if (cpumask_empty(tmp)) {
+		mutex_unlock(&round_robin_lock);
+		free_cpumask_var(tmp);
+		return;
+	}
+	for_each_cpu(cpu, tmp) {
+		if (cpu_weight[cpu] < min_weight) {
+			min_weight = cpu_weight[cpu];
+			preferred_cpu = cpu;
+		}
+	}
+
+	if (tsk_in_cpu[tsk_index] != -1)
+		cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
+	tsk_in_cpu[tsk_index] = preferred_cpu;
+	cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
+	cpu_weight[preferred_cpu]++;
+	mutex_unlock(&round_robin_lock);
+
+	set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
+
+	free_cpumask_var(tmp);
+}
+
+static void exit_round_robin(unsigned int tsk_index)
+{
+	struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
+
+	if (tsk_in_cpu[tsk_index] != -1) {
+		cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
+		tsk_in_cpu[tsk_index] = -1;
+	}
+}
+
+static unsigned int idle_pct = 5; /* percentage */
+static unsigned int round_robin_time = 1; /* second */
+static int power_saving_thread(void *data)
+{
+	int do_sleep;
+	unsigned int tsk_index = (unsigned long)data;
+	u64 last_jiffies = 0;
+
+	sched_set_fifo_low(current);
+
+	while (!kthread_should_stop()) {
+		unsigned long expire_time;
+
+		/* round robin to cpus */
+		expire_time = last_jiffies + round_robin_time * HZ;
+		if (time_before(expire_time, jiffies)) {
+			last_jiffies = jiffies;
+			round_robin_cpu(tsk_index);
+		}
+
+		do_sleep = 0;
+
+		expire_time = jiffies + HZ * (100 - idle_pct) / 100;
+
+		while (!need_resched()) {
+			if (tsc_detected_unstable && !tsc_marked_unstable) {
+				/* TSC could halt in idle, so notify users */
+				mark_tsc_unstable("TSC halts in idle");
+				tsc_marked_unstable = 1;
+			}
+			local_irq_disable();
+
+			perf_lopwr_cb(true);
+
+			tick_broadcast_enable();
+			tick_broadcast_enter();
+			stop_critical_timings();
+
+			mwait_idle_with_hints(power_saving_mwait_eax, 1);
+
+			start_critical_timings();
+			tick_broadcast_exit();
+
+			perf_lopwr_cb(false);
+
+			local_irq_enable();
+
+			if (time_before(expire_time, jiffies)) {
+				do_sleep = 1;
+				break;
+			}
+		}
+
+		/*
+		 * current sched_rt has threshold for rt task running time.
+		 * When a rt task uses 95% CPU time, the rt thread will be
+		 * scheduled out for 5% CPU time to not starve other tasks. But
+		 * the mechanism only works when all CPUs have RT task running,
+		 * as if one CPU hasn't RT task, RT task from other CPUs will
+		 * borrow CPU time from this CPU and cause RT task use > 95%
+		 * CPU time. To make 'avoid starvation' work, takes a nap here.
+		 */
+		if (unlikely(do_sleep))
+			schedule_timeout_killable(HZ * idle_pct / 100);
+
+		/* If an external event has set the need_resched flag, then
+		 * we need to deal with it, or this loop will continue to
+		 * spin without calling __mwait().
+		 */
+		if (unlikely(need_resched()))
+			schedule();
+	}
+
+	exit_round_robin(tsk_index);
+	return 0;
+}
+
+static struct task_struct *ps_tsks[NR_CPUS];
+static unsigned int ps_tsk_num;
+static int create_power_saving_task(void)
+{
+	int rc;
+
+	ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
+		(void *)(unsigned long)ps_tsk_num,
+		"acpi_pad/%d", ps_tsk_num);
+
+	if (IS_ERR(ps_tsks[ps_tsk_num])) {
+		rc = PTR_ERR(ps_tsks[ps_tsk_num]);
+		ps_tsks[ps_tsk_num] = NULL;
+	} else {
+		rc = 0;
+		ps_tsk_num++;
+	}
+
+	return rc;
+}
+
+static void destroy_power_saving_task(void)
+{
+	if (ps_tsk_num > 0) {
+		ps_tsk_num--;
+		kthread_stop(ps_tsks[ps_tsk_num]);
+		ps_tsks[ps_tsk_num] = NULL;
+	}
+}
+
+static void set_power_saving_task_num(unsigned int num)
+{
+	if (num > ps_tsk_num) {
+		while (ps_tsk_num < num) {
+			if (create_power_saving_task())
+				return;
+		}
+	} else if (num < ps_tsk_num) {
+		while (ps_tsk_num > num)
+			destroy_power_saving_task();
+	}
+}
+
+static void acpi_pad_idle_cpus(unsigned int num_cpus)
+{
+	cpus_read_lock();
+
+	num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
+	set_power_saving_task_num(num_cpus);
+
+	cpus_read_unlock();
+}
+
+static uint32_t acpi_pad_idle_cpus_num(void)
+{
+	return ps_tsk_num;
+}
+
+static ssize_t rrtime_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	unsigned long num;
+
+	if (kstrtoul(buf, 0, &num))
+		return -EINVAL;
+	if (num < 1 || num >= 100)
+		return -EINVAL;
+	mutex_lock(&isolated_cpus_lock);
+	round_robin_time = num;
+	mutex_unlock(&isolated_cpus_lock);
+	return count;
+}
+
+static ssize_t rrtime_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", round_robin_time);
+}
+static DEVICE_ATTR_RW(rrtime);
+
+static ssize_t idlepct_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	unsigned long num;
+
+	if (kstrtoul(buf, 0, &num))
+		return -EINVAL;
+	if (num < 1 || num >= 100)
+		return -EINVAL;
+	mutex_lock(&isolated_cpus_lock);
+	idle_pct = num;
+	mutex_unlock(&isolated_cpus_lock);
+	return count;
+}
+
+static ssize_t idlepct_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", idle_pct);
+}
+static DEVICE_ATTR_RW(idlepct);
+
+static ssize_t idlecpus_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	unsigned long num;
+
+	if (kstrtoul(buf, 0, &num))
+		return -EINVAL;
+	mutex_lock(&isolated_cpus_lock);
+	acpi_pad_idle_cpus(num);
+	mutex_unlock(&isolated_cpus_lock);
+	return count;
+}
+
+static ssize_t idlecpus_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%*pb\n",
+			  cpumask_pr_args(to_cpumask(pad_busy_cpus_bits)));
+}
+
+static DEVICE_ATTR_RW(idlecpus);
+
+static struct attribute *acpi_pad_attrs[] = {
+	&dev_attr_idlecpus.attr,
+	&dev_attr_idlepct.attr,
+	&dev_attr_rrtime.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(acpi_pad);
+
+/*
+ * Query firmware how many CPUs should be idle
+ * return -1 on failure
+ */
+static int acpi_pad_pur(acpi_handle handle)
+{
+	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
+	union acpi_object *package;
+	int num = -1;
+
+	if (unlikely(acpi_pad_teardown))
+		return -1;
+
+	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
+		return num;
+
+	if (!buffer.length || !buffer.pointer)
+		return num;
+
+	package = buffer.pointer;
+
+	if (package->type == ACPI_TYPE_PACKAGE &&
+		package->package.count == 2 &&
+		package->package.elements[0].integer.value == 1) /* rev 1 */
+
+		num = package->package.elements[1].integer.value;
+
+	kfree(buffer.pointer);
+	return num;
+}
+
+static void acpi_pad_handle_notify(acpi_handle handle)
+{
+	int num_cpus;
+	uint32_t idle_cpus;
+	struct acpi_buffer param = {
+		.length = 4,
+		.pointer = (void *)&idle_cpus,
+	};
+	u32 status;
+
+	mutex_lock(&isolated_cpus_lock);
+	num_cpus = acpi_pad_pur(handle);
+	if (num_cpus < 0) {
+		/* The ACPI specification says that if no action was performed when
+		 * processing the _PUR object, _OST should still be evaluated, albeit
+		 * with a different status code.
+		 */
+		status = ACPI_PROCESSOR_AGGREGATOR_STATUS_NO_ACTION;
+	} else {
+		status = ACPI_PROCESSOR_AGGREGATOR_STATUS_SUCCESS;
+		acpi_pad_idle_cpus(num_cpus);
+	}
+
+	idle_cpus = acpi_pad_idle_cpus_num();
+	acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, status, &param);
+	mutex_unlock(&isolated_cpus_lock);
+}
+
+static void acpi_pad_notify(acpi_handle handle, u32 event, void *data)
+{
+	if (event != ACPI_PROCESSOR_AGGREGATOR_NOTIFY) {
+		pr_warn("Unsupported event [0x%x]\n", event);
+		return;
+	}
+
+	acpi_pad_handle_notify(handle);
+	acpi_bus_generate_netlink_event("acpi_pad", dev_name(data), event, 0);
+}
+
+static int acpi_pad_probe(struct platform_device *pdev)
+{
+	acpi_pad_teardown = false;
+
+	return devm_acpi_install_notify_handler(&pdev->dev, ACPI_DEVICE_NOTIFY,
+						acpi_pad_notify, &pdev->dev);
+}
+
+static void acpi_pad_remove(struct platform_device *pdev)
+{
+	mutex_lock(&isolated_cpus_lock);
+	acpi_pad_teardown = true;
+	acpi_pad_idle_cpus(0);
+	mutex_unlock(&isolated_cpus_lock);
+}
+
+static const struct acpi_device_id pad_device_ids[] = {
+	{"ACPI000C", 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, pad_device_ids);
+
+static struct platform_driver acpi_pad_driver = {
+	.probe = acpi_pad_probe,
+	.remove = acpi_pad_remove,
+	.driver = {
+		.dev_groups = acpi_pad_groups,
+		.name = "processor_aggregator",
+		.acpi_match_table = pad_device_ids,
+	},
+};
+
+static int __init acpi_pad_init(void)
+{
+	/* Xen ACPI PAD is used when running as Xen Dom0. */
+	if (xen_initial_domain())
+		return -ENODEV;
+
+	power_saving_mwait_init();
+	if (power_saving_mwait_eax == 0)
+		return -EINVAL;
+
+	return platform_driver_register(&acpi_pad_driver);
+}
+
+static void __exit acpi_pad_exit(void)
+{
+	platform_driver_unregister(&acpi_pad_driver);
+}
+
+module_init(acpi_pad_init);
+module_exit(acpi_pad_exit);
+MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
+MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
+MODULE_LICENSE("GPL");