Merge tag 'trace-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:
 "User visible changes:

   - Add an entry into MAINTAINERS file for RUST versions of code

     There's now RUST code for tracing and static branches. To
     differentiate that code from the C code, add entries in for the
     RUST version (with "[RUST]" around it) so that the right
     maintainers get notified on changes.

   - New bitmask-list option added to tracefs

     When this is set, bitmasks in trace event are not displayed as hex
     numbers, but instead as lists: e.g. 0-5,7,9 instead of 0000015f

   - New show_event_filters file in tracefs

     Instead of having to search all events/*/*/filter for any active
     filters enabled in the trace instance, the file show_event_filters
     will list them so that there's only one file that needs to be
     examined to see if any filters are active.

   - New show_event_triggers file in tracefs

     Instead of having to search all events/*/*/trigger for any active
     triggers enabled in the trace instance, the file
     show_event_triggers will list them so that there's only one file
     that needs to be examined to see if any triggers are active.

   - Have traceoff_on_warning disable trace pintk buffer too

     Recently recording of trace_printk() could go to other trace
     instances instead of the top level instance. But if
     traceoff_on_warning triggers, it doesn't stop the buffer with
     trace_printk() and that data can easily be lost by being
     overwritten. Have traceoff_on_warning also disable the instance
     that has trace_printk() being written to it.

   - Update the hist_debug file to show what function the field uses

     When CONFIG_HIST_TRIGGERS_DEBUG is enabled, a hist_debug file
     exists for every event. This displays the internal data of any
     histogram enabled for that event. But it is lacking the function
     that is called to process one of its fields. This is very useful
     information that was missing when debugging histograms.

   - Up the histogram stack size from 16 to 31

     Stack traces can be used as keys for event histograms. Currently
     the size of the stack that is stored is limited to just 16 entries.
     But the storage space in the histogram is 256 bytes, meaning that
     it can store up to 31 entries (plus one for the count of entries).
     Instead of letting that space go to waste, up the limit from 16 to
     31. This makes the keys much more useful.

   - Fix permissions of per CPU file buffer_size_kb

     The per CPU file of buffer_size_kb was incorrectly set to read only
     in a previous cleanup. It should be writable.

   - Reset "last_boot_info" if the persistent buffer is cleared

     The last_boot_info shows address information of a persistent ring
     buffer if it contains data from a previous boot. It is cleared when
     recording starts again, but it is not cleared when the buffer is
     reset. The data is useless after a reset so clear it on reset too.

  Internal changes:

   - A change was made to allow tracepoint callbacks to have preemption
     enabled, and instead be protected by SRCU. This required some
     updates to the callbacks for perf and BPF.

     perf needed to disable preemption directly in its callback because
     it expects preemption disabled in the later code.

     BPF needed to disable migration, as its code expects to run
     completely on the same CPU.

   - Have irq_work wake up other CPU if current CPU is "isolated"

     When there's a waiter waiting on ring buffer data and a new event
     happens, an irq work is triggered to wake up that waiter. This is
     noisy on isolated CPUs (running NO_HZ_FULL). Trigger an IPI to a
     house keeping CPU instead.

   - Use proper free of trigger_data instead of open coding it in.

   - Remove redundant call of event_trigger_reset_filter()

     It was called immediately in a function that was called right after
     it.

   - Workqueue cleanups

   - Report errors if tracing_update_buffers() were to fail.

   - Make the enum update workqueue generic for other parts of tracing

     On boot up, a work queue is created to convert enum names into
     their numbers in the trace event format files. This work queue can
     also be used for other aspects of tracing that takes some time and
     shouldn't be called by the init call code.

     The blk_trace initialization takes a bit of time. Have the
     initialization code moved to the new tracing generic work queue
     function.

   - Skip kprobe boot event creation call if there's no kprobes defined
     on cmdline

     The kprobe initialization to set up kprobes if they are defined on
     the cmdline requires taking the event_mutex lock. This can be held
     by other tracing code doing initialization for a long time. Since
     kprobes added to the kernel command line need to be setup
     immediately, as they may be tracing early initialization code, they
     cannot be postponed in a work queue and must be setup in the
     initcall code.

     If there's no kprobe on the kernel cmdline, there's no reason to
     take the mutex and slow down the boot up code waiting to get the
     lock only to find out there's nothing to do. Simply exit out early
     if there's no kprobes on the kernel cmdline.

     If there are kprobes on the cmdline, then someone cares more about
     tracing over the speed of boot up.

   - Clean up the trigger code a bit

   - Move code out of trace.c and into their own files

     trace.c is now over 11,000 lines of code and has become more
     difficult to maintain. Start splitting it up so that related code
     is in their own files.

     Move all the trace_printk() related code into trace_printk.c.

     Move the __always_inline stack functions into trace.h.

     Move the pid filtering code into a new trace_pid.c file.

   - Better define the max latency and snapshot code

     The latency tracers have a "max latency" buffer that is a copy of
     the main buffer and gets swapped with it when a new high latency is
     detected. This keeps the trace up to the highest latency around
     where this max_latency buffer is never written to. It is only used
     to save the last max latency trace.

     A while ago a snapshot feature was added to tracefs to allow user
     space to perform the same logic. It could also enable events to
     trigger a "snapshot" if one of their fields hit a new high. This
     was built on top of the latency max_latency buffer logic.

     Because snapshots came later, they were dependent on the latency
     tracers to be enabled. In reality, the latency tracers depend on
     the snapshot code and not the other way around. It was just that
     they came first.

     Restructure the code and the kconfigs to have the latency tracers
     depend on snapshot code instead. This actually simplifies the logic
     a bit and allows to disable more when the latency tracers are not
     defined and the snapshot code is.

   - Fix a "false sharing" in the hwlat tracer code

     The loop to search for latency in hardware was using a variable
     that could be changed by user space for each sample. If the user
     change this variable, it could cause a bus contention, and reading
     that variable can show up as a large latency in the trace causing a
     false positive. Read this variable at the start of the sample with
     a READ_ONCE() into a local variable and keep the code from sharing
     cache lines with readers.

   - Fix function graph tracer static branch optimization code

     When only one tracer is defined for function graph tracing, it uses
     a static branch to call that tracer directly. When another tracer
     is added, it goes into loop logic to call all the registered
     callbacks.

     The code was incorrect when going back to one tracer and never
     re-enabled the static branch again to do the optimization code.

   - And other small fixes and cleanups"

* tag 'trace-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (46 commits)
  function_graph: Restore direct mode when callbacks drop to one
  tracing: Fix indentation of return statement in print_trace_fmt()
  tracing: Reset last_boot_info if ring buffer is reset
  tracing: Fix to set write permission to per-cpu buffer_size_kb
  tracing: Fix false sharing in hwlat get_sample()
  tracing: Move d_max_latency out of CONFIG_FSNOTIFY protection
  tracing: Better separate SNAPSHOT and MAX_TRACE options
  tracing: Add tracer_uses_snapshot() helper to remove #ifdefs
  tracing: Rename trace_array field max_buffer to snapshot_buffer
  tracing: Move pid filtering into trace_pid.c
  tracing: Move trace_printk functions out of trace.c and into trace_printk.c
  tracing: Use system_state in trace_printk_init_buffers()
  tracing: Have trace_printk functions use flags instead of using global_trace
  tracing: Make tracing_update_buffers() take NULL for global_trace
  tracing: Make printk_trace global for tracing system
  tracing: Move ftrace_trace_stack() out of trace.c and into trace.h
  tracing: Move __trace_buffer_{un}lock_*() functions to trace.h
  tracing: Make tracing_selftest_running global to the tracing subsystem
  tracing: Make tracing_disabled global for tracing system
  tracing: Clean up use of trace_create_maxlat_file()
  ...

21 files changed, 1306 insertions, 1053 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d7042a09fe46..49de13cae428 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -136,6 +136,7 @@ config BUILDTIME_MCOUNT_SORT
 
 config TRACER_MAX_TRACE
 	bool
+	select TRACER_SNAPSHOT
 
 config TRACE_CLOCK
 	bool
@@ -425,7 +426,6 @@ config IRQSOFF_TRACER
 	select GENERIC_TRACER
 	select TRACER_MAX_TRACE
 	select RING_BUFFER_ALLOW_SWAP
-	select TRACER_SNAPSHOT
 	select TRACER_SNAPSHOT_PER_CPU_SWAP
 	help
 	  This option measures the time spent in irqs-off critical
@@ -448,7 +448,6 @@ config PREEMPT_TRACER
 	select GENERIC_TRACER
 	select TRACER_MAX_TRACE
 	select RING_BUFFER_ALLOW_SWAP
-	select TRACER_SNAPSHOT
 	select TRACER_SNAPSHOT_PER_CPU_SWAP
 	select TRACE_PREEMPT_TOGGLE
 	help
@@ -470,7 +469,6 @@ config SCHED_TRACER
 	select GENERIC_TRACER
 	select CONTEXT_SWITCH_TRACER
 	select TRACER_MAX_TRACE
-	select TRACER_SNAPSHOT
 	help
 	  This tracer tracks the latency of the highest priority task
 	  to be scheduled in, starting from the point it has woken up.
@@ -620,7 +618,6 @@ config TRACE_SYSCALL_BUF_SIZE_DEFAULT
 
 config TRACER_SNAPSHOT
 	bool "Create a snapshot trace buffer"
-	select TRACER_MAX_TRACE
 	help
 	  Allow tracing users to take snapshot of the current buffer using the
 	  ftrace interface, e.g.:
@@ -628,6 +625,9 @@ config TRACER_SNAPSHOT
 	      echo 1 > /sys/kernel/tracing/snapshot
 	      cat snapshot
 
+	  Note, the latency tracers select this option. To disable it,
+	  all the latency tracers need to be disabled.
+
 config TRACER_SNAPSHOT_PER_CPU_SWAP
 	bool "Allow snapshot to swap per CPU"
 	depends on TRACER_SNAPSHOT
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index fc5dcc888e13..04096c21d06b 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_TRACING) += trace_output.o
 obj-$(CONFIG_TRACING) += trace_seq.o
 obj-$(CONFIG_TRACING) += trace_stat.o
 obj-$(CONFIG_TRACING) += trace_printk.o
+obj-$(CONFIG_TRACING) += trace_pid.o
 obj-$(CONFIG_TRACING) += 	pid_list.o
 obj-$(CONFIG_TRACING_MAP) += tracing_map.o
 obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index c4db5c2e7103..f2de9cf15d0e 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1832,7 +1832,9 @@ static struct trace_event trace_blk_event = {
 	.funcs		= &trace_blk_event_funcs,
 };
 
-static int __init init_blk_tracer(void)
+static struct work_struct blktrace_works __initdata;
+
+static int __init __init_blk_tracer(void)
 {
 	if (!register_trace_event(&trace_blk_event)) {
 		pr_warn("Warning: could not register block events\n");
@@ -1852,6 +1854,25 @@ static int __init init_blk_tracer(void)
 	return 0;
 }
 
+static void __init blktrace_works_func(struct work_struct *work)
+{
+	__init_blk_tracer();
+}
+
+static int __init init_blk_tracer(void)
+{
+	int ret = 0;
+
+	if (trace_init_wq) {
+		INIT_WORK(&blktrace_works, blktrace_works_func);
+		queue_work(trace_init_wq, &blktrace_works);
+	} else {
+		ret = __init_blk_tracer();
+	}
+
+	return ret;
+}
+
 device_initcall(init_blk_tracer);
 
 static int blk_trace_remove_queue(struct request_queue *q)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index f7baeb8278ca..eadaef8592a3 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2076,7 +2076,7 @@ void __bpf_trace_run(struct bpf_raw_tp_link *link, u64 *args)
 	struct bpf_run_ctx *old_run_ctx;
 	struct bpf_trace_run_ctx run_ctx;
 
-	cant_sleep();
+	rcu_read_lock_dont_migrate();
 	if (unlikely(!bpf_prog_get_recursion_context(prog))) {
 		bpf_prog_inc_misses_counter(prog);
 		goto out;
@@ -2085,13 +2085,12 @@ void __bpf_trace_run(struct bpf_raw_tp_link *link, u64 *args)
 	run_ctx.bpf_cookie = link->cookie;
 	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
 
-	rcu_read_lock();
 	(void) bpf_prog_run(prog, args);
-	rcu_read_unlock();
 
 	bpf_reset_run_ctx(old_run_ctx);
 out:
 	bpf_prog_put_recursion_context(prog);
+	rcu_read_unlock_migrate();
 }
 
 #define UNPACK(...)			__VA_ARGS__
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index cc48d16be43e..4df766c690f9 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -1303,7 +1303,7 @@ static void ftrace_graph_enable_direct(bool enable_branch, struct fgraph_ops *go
 	static_call_update(fgraph_func, func);
 	static_call_update(fgraph_retfunc, retfunc);
 	if (enable_branch)
-		static_branch_disable(&fgraph_do_direct);
+		static_branch_enable(&fgraph_do_direct);
 }
 
 static void ftrace_graph_disable_direct(bool disable_branch)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8fb38722fd5c..1ce17c8af409 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1147,6 +1147,7 @@ struct ftrace_page {
 };
 
 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
+#define ENTRIES_PER_PAGE_GROUP(order) ((PAGE_SIZE << (order)) / ENTRY_SIZE)
 
 static struct ftrace_page	*ftrace_pages_start;
 static struct ftrace_page	*ftrace_pages;
@@ -3873,7 +3874,7 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count,
 	*num_pages += 1 << order;
 	ftrace_number_of_groups++;
 
-	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
+	cnt = ENTRIES_PER_PAGE_GROUP(order);
 	pg->order = order;
 
 	if (cnt > count)
@@ -7668,7 +7669,7 @@ static int ftrace_process_locs(struct module *mod,
 		long skip;
 
 		/* Count the number of entries unused and compare it to skipped. */
-		pg_remaining = (PAGE_SIZE << pg->order) / ENTRY_SIZE - pg->index;
+		pg_remaining = ENTRIES_PER_PAGE_GROUP(pg->order) - pg->index;
 
 		if (!WARN(skipped < pg_remaining, "Extra allocated pages for ftrace")) {
 
@@ -7676,7 +7677,7 @@ static int ftrace_process_locs(struct module *mod,
 
 			for (pg = pg_unuse; pg && skip > 0; pg = pg->next) {
 				remaining += 1 << pg->order;
-				skip -= (PAGE_SIZE << pg->order) / ENTRY_SIZE;
+				skip -= ENTRIES_PER_PAGE_GROUP(pg->order);
 			}
 
 			pages -= remaining;
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 630221b00838..d33103408955 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4,6 +4,7 @@
  *
  * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
  */
+#include <linux/sched/isolation.h>
 #include <linux/trace_recursion.h>
 #include <linux/trace_events.h>
 #include <linux/ring_buffer.h>
@@ -4013,19 +4014,36 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer)
 	rb_end_commit(cpu_buffer);
 }
 
+static bool
+rb_irq_work_queue(struct rb_irq_work *irq_work)
+{
+	int cpu;
+
+	/* irq_work_queue_on() is not NMI-safe */
+	if (unlikely(in_nmi()))
+		return irq_work_queue(&irq_work->work);
+
+	/*
+	 * If CPU isolation is not active, cpu is always the current
+	 * CPU, and the following is equivallent to irq_work_queue().
+	 */
+	cpu = housekeeping_any_cpu(HK_TYPE_KERNEL_NOISE);
+	return irq_work_queue_on(&irq_work->work, cpu);
+}
+
 static __always_inline void
 rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 {
 	if (buffer->irq_work.waiters_pending) {
 		buffer->irq_work.waiters_pending = false;
 		/* irq_work_queue() supplies it's own memory barriers */
-		irq_work_queue(&buffer->irq_work.work);
+		rb_irq_work_queue(&buffer->irq_work);
 	}
 
 	if (cpu_buffer->irq_work.waiters_pending) {
 		cpu_buffer->irq_work.waiters_pending = false;
 		/* irq_work_queue() supplies it's own memory barriers */
-		irq_work_queue(&cpu_buffer->irq_work.work);
+		rb_irq_work_queue(&cpu_buffer->irq_work);
 	}
 
 	if (cpu_buffer->last_pages_touch == local_read(&cpu_buffer->pages_touched))
@@ -4045,7 +4063,7 @@ rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 	cpu_buffer->irq_work.wakeup_full = true;
 	cpu_buffer->irq_work.full_waiters_pending = false;
 	/* irq_work_queue() supplies it's own memory barriers */
-	irq_work_queue(&cpu_buffer->irq_work.work);
+	rb_irq_work_queue(&cpu_buffer->irq_work);
 }
 
 #ifdef CONFIG_RING_BUFFER_RECORD_RECURSION
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b1cb30a7b83d..2f6fbf9e7caf 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -67,7 +67,7 @@
  * insertions into the ring-buffer such as trace_printk could occurred
  * at the same time, giving false positive or negative results.
  */
-static bool __read_mostly tracing_selftest_running;
+bool __read_mostly tracing_selftest_running;
 
 /*
  * If boot-time tracing including tracers/events via kernel cmdline
@@ -83,7 +83,6 @@ void __init disable_tracing_selftest(const char *reason)
 	}
 }
 #else
-#define tracing_selftest_running	0
 #define tracing_selftest_disabled	0
 #endif
 
@@ -114,7 +113,7 @@ DEFINE_PER_CPU(bool, trace_taskinfo_save);
  * of the tracer is successful. But that is the only place that sets
  * this back to zero.
  */
-static int tracing_disabled = 1;
+int tracing_disabled = 1;
 
 cpumask_var_t __read_mostly	tracing_buffer_mask;
 
@@ -535,22 +534,11 @@ static struct trace_array global_trace = {
 	.trace_flags = TRACE_DEFAULT_FLAGS,
 };
 
-static struct trace_array *printk_trace = &global_trace;
+struct trace_array *printk_trace = &global_trace;
 
 /* List of trace_arrays interested in the top level trace_marker */
 static LIST_HEAD(marker_copies);
 
-static __always_inline bool printk_binsafe(struct trace_array *tr)
-{
-	/*
-	 * The binary format of traceprintk can cause a crash if used
-	 * by a buffer from another boot. Force the use of the
-	 * non binary version of trace_printk if the trace_printk
-	 * buffer is a boot mapped ring buffer.
-	 */
-	return !(tr->flags & TRACE_ARRAY_FL_BOOT);
-}
-
 static void update_printk_trace(struct trace_array *tr)
 {
 	if (printk_trace == tr)
@@ -649,248 +637,6 @@ int tracing_check_open_get_tr(struct trace_array *tr)
 	return 0;
 }
 
-/**
- * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
- * @filtered_pids: The list of pids to check
- * @search_pid: The PID to find in @filtered_pids
- *
- * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
- */
-bool
-trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
-{
-	return trace_pid_list_is_set(filtered_pids, search_pid);
-}
-
-/**
- * trace_ignore_this_task - should a task be ignored for tracing
- * @filtered_pids: The list of pids to check
- * @filtered_no_pids: The list of pids not to be traced
- * @task: The task that should be ignored if not filtered
- *
- * Checks if @task should be traced or not from @filtered_pids.
- * Returns true if @task should *NOT* be traced.
- * Returns false if @task should be traced.
- */
-bool
-trace_ignore_this_task(struct trace_pid_list *filtered_pids,
-		       struct trace_pid_list *filtered_no_pids,
-		       struct task_struct *task)
-{
-	/*
-	 * If filtered_no_pids is not empty, and the task's pid is listed
-	 * in filtered_no_pids, then return true.
-	 * Otherwise, if filtered_pids is empty, that means we can
-	 * trace all tasks. If it has content, then only trace pids
-	 * within filtered_pids.
-	 */
-
-	return (filtered_pids &&
-		!trace_find_filtered_pid(filtered_pids, task->pid)) ||
-		(filtered_no_pids &&
-		 trace_find_filtered_pid(filtered_no_pids, task->pid));
-}
-
-/**
- * trace_filter_add_remove_task - Add or remove a task from a pid_list
- * @pid_list: The list to modify
- * @self: The current task for fork or NULL for exit
- * @task: The task to add or remove
- *
- * If adding a task, if @self is defined, the task is only added if @self
- * is also included in @pid_list. This happens on fork and tasks should
- * only be added when the parent is listed. If @self is NULL, then the
- * @task pid will be removed from the list, which would happen on exit
- * of a task.
- */
-void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
-				  struct task_struct *self,
-				  struct task_struct *task)
-{
-	if (!pid_list)
-		return;
-
-	/* For forks, we only add if the forking task is listed */
-	if (self) {
-		if (!trace_find_filtered_pid(pid_list, self->pid))
-			return;
-	}
-
-	/* "self" is set for forks, and NULL for exits */
-	if (self)
-		trace_pid_list_set(pid_list, task->pid);
-	else
-		trace_pid_list_clear(pid_list, task->pid);
-}
-
-/**
- * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
- * @pid_list: The pid list to show
- * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
- * @pos: The position of the file
- *
- * This is used by the seq_file "next" operation to iterate the pids
- * listed in a trace_pid_list structure.
- *
- * Returns the pid+1 as we want to display pid of zero, but NULL would
- * stop the iteration.
- */
-void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
-{
-	long pid = (unsigned long)v;
-	unsigned int next;
-
-	(*pos)++;
-
-	/* pid already is +1 of the actual previous bit */
-	if (trace_pid_list_next(pid_list, pid, &next) < 0)
-		return NULL;
-
-	pid = next;
-
-	/* Return pid + 1 to allow zero to be represented */
-	return (void *)(pid + 1);
-}
-
-/**
- * trace_pid_start - Used for seq_file to start reading pid lists
- * @pid_list: The pid list to show
- * @pos: The position of the file
- *
- * This is used by seq_file "start" operation to start the iteration
- * of listing pids.
- *
- * Returns the pid+1 as we want to display pid of zero, but NULL would
- * stop the iteration.
- */
-void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
-{
-	unsigned long pid;
-	unsigned int first;
-	loff_t l = 0;
-
-	if (trace_pid_list_first(pid_list, &first) < 0)
-		return NULL;
-
-	pid = first;
-
-	/* Return pid + 1 so that zero can be the exit value */
-	for (pid++; pid && l < *pos;
-	     pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
-		;
-	return (void *)pid;
-}
-
-/**
- * trace_pid_show - show the current pid in seq_file processing
- * @m: The seq_file structure to write into
- * @v: A void pointer of the pid (+1) value to display
- *
- * Can be directly used by seq_file operations to display the current
- * pid value.
- */
-int trace_pid_show(struct seq_file *m, void *v)
-{
-	unsigned long pid = (unsigned long)v - 1;
-
-	seq_printf(m, "%lu\n", pid);
-	return 0;
-}
-
-/* 128 should be much more than enough */
-#define PID_BUF_SIZE		127
-
-int trace_pid_write(struct trace_pid_list *filtered_pids,
-		    struct trace_pid_list **new_pid_list,
-		    const char __user *ubuf, size_t cnt)
-{
-	struct trace_pid_list *pid_list;
-	struct trace_parser parser;
-	unsigned long val;
-	int nr_pids = 0;
-	ssize_t read = 0;
-	ssize_t ret;
-	loff_t pos;
-	pid_t pid;
-
-	if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
-		return -ENOMEM;
-
-	/*
-	 * Always recreate a new array. The write is an all or nothing
-	 * operation. Always create a new array when adding new pids by
-	 * the user. If the operation fails, then the current list is
-	 * not modified.
-	 */
-	pid_list = trace_pid_list_alloc();
-	if (!pid_list) {
-		trace_parser_put(&parser);
-		return -ENOMEM;
-	}
-
-	if (filtered_pids) {
-		/* copy the current bits to the new max */
-		ret = trace_pid_list_first(filtered_pids, &pid);
-		while (!ret) {
-			ret = trace_pid_list_set(pid_list, pid);
-			if (ret < 0)
-				goto out;
-
-			ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
-			nr_pids++;
-		}
-	}
-
-	ret = 0;
-	while (cnt > 0) {
-
-		pos = 0;
-
-		ret = trace_get_user(&parser, ubuf, cnt, &pos);
-		if (ret < 0)
-			break;
-
-		read += ret;
-		ubuf += ret;
-		cnt -= ret;
-
-		if (!trace_parser_loaded(&parser))
-			break;
-
-		ret = -EINVAL;
-		if (kstrtoul(parser.buffer, 0, &val))
-			break;
-
-		pid = (pid_t)val;
-
-		if (trace_pid_list_set(pid_list, pid) < 0) {
-			ret = -1;
-			break;
-		}
-		nr_pids++;
-
-		trace_parser_clear(&parser);
-		ret = 0;
-	}
- out:
-	trace_parser_put(&parser);
-
-	if (ret < 0) {
-		trace_pid_list_free(pid_list);
-		return ret;
-	}
-
-	if (!nr_pids) {
-		/* Cleared the list of pids */
-		trace_pid_list_free(pid_list);
-		pid_list = NULL;
-	}
-
-	*new_pid_list = pid_list;
-
-	return read;
-}
-
 static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
 {
 	u64 ts;
@@ -1033,56 +779,6 @@ static inline void trace_access_lock_init(void)
 
 #endif
 
-#ifdef CONFIG_STACKTRACE
-static void __ftrace_trace_stack(struct trace_array *tr,
-				 struct trace_buffer *buffer,
-				 unsigned int trace_ctx,
-				 int skip, struct pt_regs *regs);
-static inline void ftrace_trace_stack(struct trace_array *tr,
-				      struct trace_buffer *buffer,
-				      unsigned int trace_ctx,
-				      int skip, struct pt_regs *regs);
-
-#else
-static inline void __ftrace_trace_stack(struct trace_array *tr,
-					struct trace_buffer *buffer,
-					unsigned int trace_ctx,
-					int skip, struct pt_regs *regs)
-{
-}
-static inline void ftrace_trace_stack(struct trace_array *tr,
-				      struct trace_buffer *buffer,
-				      unsigned long trace_ctx,
-				      int skip, struct pt_regs *regs)
-{
-}
-
-#endif
-
-static __always_inline void
-trace_event_setup(struct ring_buffer_event *event,
-		  int type, unsigned int trace_ctx)
-{
-	struct trace_entry *ent = ring_buffer_event_data(event);
-
-	tracing_generic_entry_update(ent, type, trace_ctx);
-}
-
-static __always_inline struct ring_buffer_event *
-__trace_buffer_lock_reserve(struct trace_buffer *buffer,
-			  int type,
-			  unsigned long len,
-			  unsigned int trace_ctx)
-{
-	struct ring_buffer_event *event;
-
-	event = ring_buffer_lock_reserve(buffer, len);
-	if (event != NULL)
-		trace_event_setup(event, type, trace_ctx);
-
-	return event;
-}
-
 void tracer_tracing_on(struct trace_array *tr)
 {
 	if (tr->array_buffer.buffer)
@@ -1110,129 +806,10 @@ void tracing_on(void)
 }
 EXPORT_SYMBOL_GPL(tracing_on);
 
-
-static __always_inline void
-__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
-{
-	__this_cpu_write(trace_taskinfo_save, true);
-
-	/* If this is the temp buffer, we need to commit fully */
-	if (this_cpu_read(trace_buffered_event) == event) {
-		/* Length is in event->array[0] */
-		ring_buffer_write(buffer, event->array[0], &event->array[1]);
-		/* Release the temp buffer */
-		this_cpu_dec(trace_buffered_event_cnt);
-		/* ring_buffer_unlock_commit() enables preemption */
-		preempt_enable_notrace();
-	} else
-		ring_buffer_unlock_commit(buffer);
-}
-
-int __trace_array_puts(struct trace_array *tr, unsigned long ip,
-		       const char *str, int size)
-{
-	struct ring_buffer_event *event;
-	struct trace_buffer *buffer;
-	struct print_entry *entry;
-	unsigned int trace_ctx;
-	int alloc;
-
-	if (!(tr->trace_flags & TRACE_ITER(PRINTK)))
-		return 0;
-
-	if (unlikely(tracing_selftest_running && tr == &global_trace))
-		return 0;
-
-	if (unlikely(tracing_disabled))
-		return 0;
-
-	alloc = sizeof(*entry) + size + 2; /* possible \n added */
-
-	trace_ctx = tracing_gen_ctx();
-	buffer = tr->array_buffer.buffer;
-	guard(ring_buffer_nest)(buffer);
-	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
-					    trace_ctx);
-	if (!event)
-		return 0;
-
-	entry = ring_buffer_event_data(event);
-	entry->ip = ip;
-
-	memcpy(&entry->buf, str, size);
-
-	/* Add a newline if necessary */
-	if (entry->buf[size - 1] != '\n') {
-		entry->buf[size] = '\n';
-		entry->buf[size + 1] = '\0';
-	} else
-		entry->buf[size] = '\0';
-
-	__buffer_unlock_commit(buffer, event);
-	ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
-	return size;
-}
-EXPORT_SYMBOL_GPL(__trace_array_puts);
-
-/**
- * __trace_puts - write a constant string into the trace buffer.
- * @ip:	   The address of the caller
- * @str:   The constant string to write
- */
-int __trace_puts(unsigned long ip, const char *str)
-{
-	return __trace_array_puts(printk_trace, ip, str, strlen(str));
-}
-EXPORT_SYMBOL_GPL(__trace_puts);
-
-/**
- * __trace_bputs - write the pointer to a constant string into trace buffer
- * @ip:	   The address of the caller
- * @str:   The constant string to write to the buffer to
- */
-int __trace_bputs(unsigned long ip, const char *str)
-{
-	struct trace_array *tr = READ_ONCE(printk_trace);
-	struct ring_buffer_event *event;
-	struct trace_buffer *buffer;
-	struct bputs_entry *entry;
-	unsigned int trace_ctx;
-	int size = sizeof(struct bputs_entry);
-
-	if (!printk_binsafe(tr))
-		return __trace_puts(ip, str);
-
-	if (!(tr->trace_flags & TRACE_ITER(PRINTK)))
-		return 0;
-
-	if (unlikely(tracing_selftest_running || tracing_disabled))
-		return 0;
-
-	trace_ctx = tracing_gen_ctx();
-	buffer = tr->array_buffer.buffer;
-
-	guard(ring_buffer_nest)(buffer);
-	event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
-					    trace_ctx);
-	if (!event)
-		return 0;
-
-	entry = ring_buffer_event_data(event);
-	entry->ip			= ip;
-	entry->str			= str;
-
-	__buffer_unlock_commit(buffer, event);
-	ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
-
-	return 1;
-}
-EXPORT_SYMBOL_GPL(__trace_bputs);
-
 #ifdef CONFIG_TRACER_SNAPSHOT
 static void tracing_snapshot_instance_cond(struct trace_array *tr,
 					   void *cond_data)
 {
-	struct tracer *tracer = tr->current_trace;
 	unsigned long flags;
 
 	if (in_nmi()) {
@@ -1248,15 +825,15 @@ static void tracing_snapshot_instance_cond(struct trace_array *tr,
 		return;
 	}
 
-	/* Note, snapshot can not be used when the tracer uses it */
-	if (tracer->use_max_tr) {
-		trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
+	if (tr->mapped) {
+		trace_array_puts(tr, "*** BUFFER MEMORY MAPPED ***\n");
 		trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
 		return;
 	}
 
-	if (tr->mapped) {
-		trace_array_puts(tr, "*** BUFFER MEMORY MAPPED ***\n");
+	/* Note, snapshot can not be used when the tracer uses it */
+	if (tracer_uses_snapshot(tr->current_