Merge tag 'trace-v6.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Remove redundant __GFP_NOWARN flag is kmalloc

   As now __GFP_NOWARN is part of __GFP_NOWAIT, it can be removed from
   kmalloc as it is redundant.

 - Use copy_from_user_nofault() instead of _inatomic() for trace markers

   The trace_marker files are written to to allow user space to quickly
   write into the tracing ring buffer.

   Back in 2016, the get_user_pages_fast() and the kmap() logic was
   replaced by a __copy_from_user_inatomic(), but didn't properly
   disable page faults around it.

   Since the time this was added, copy_from_user_nofault() was added
   which does the required page fault disabling for us.

 - Fix the assembly markup in the ftrace direct sample code

   The ftrace direct sample code (which is also used for selftests), had
   the size directive between the "leave" and the "ret" instead of after
   the ret. This caused objtool to think the code was unreachable.

 - Only call unregister_pm_notifier() on outer most fgraph registration

   There was an error path in register_ftrace_graph() that did not call
   unregister_pm_notifier() on error, so it was added in the error path.
   The problem with that fix, is that register_pm_notifier() is only
   called by the initial user of fgraph. If that succeeds, but another
   fgraph registration were to fail, then unregister_pm_notifier() would
   be called incorrectly.

 - Fix a crash in osnoise when zero size cpumask is passed in

   If a zero size CPU mask is passed in, the kmalloc() would return
   ZERO_SIZE_PTR which is not checked, and the code would continue
   thinking it had real memory and crash. If zero is passed in as the
   size of the write, simply return 0.

 - Fix possible warning in trace_pid_write()

   If while processing a series of numbers passed to the "set_event_pid"
   file, and one of the updates fails to allocate (triggered by a fault
   injection), it can cause a warning to trigger. Check the return value
   of the call to trace_pid_list_set() and break out early with an error
   code if it fails.

* tag 'trace-v6.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Silence warning when chunk allocation fails in trace_pid_write
  tracing/osnoise: Fix null-ptr-deref in bitmap_parselist()
  trace/fgraph: Fix error handling
  ftrace/samples: Fix function size computation
  tracing: Fix tracing_marker may trigger page fault during preempt_disable
  trace: Remove redundant __GFP_NOWARN

Author: torvalds

kernel/trace/fgraph.c

@@ -1397,7 +1397,8 @@ int register_ftrace_graph(struct fgraph_ops *gops)
 		ftrace_graph_active--;
 		gops->saved_func = NULL;
 		fgraph_lru_release_index(i);
-		unregister_pm_notifier(&ftrace_suspend_notifier);
+		if (!ftrace_graph_active)
+			unregister_pm_notifier(&ftrace_suspend_notifier);
 	}
 	return ret;
 }

kernel/trace/trace.c

@@ -834,7 +834,10 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
 		/* copy the current bits to the new max */
 		ret = trace_pid_list_first(filtered_pids, &pid);
 		while (!ret) {
-			trace_pid_list_set(pid_list, pid);
+			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++;
 		}
@@ -871,6 +874,7 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
 		trace_parser_clear(&parser);
 		ret = 0;
 	}
+ out:
 	trace_parser_put(&parser);
 
 	if (ret < 0) {
@@ -7209,7 +7213,7 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user
 	entry = ring_buffer_event_data(event);
 	entry->ip = ip;
 
-	len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
+	len = copy_from_user_nofault(&entry->buf, ubuf, cnt);
 	if (len) {
 		memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
 		cnt = FAULTED_SIZE;
@@ -7306,7 +7310,7 @@ static ssize_t write_raw_marker_to_buffer(struct trace_array *tr,
 
 	entry = ring_buffer_event_data(event);
 
-	len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
+	len = copy_from_user_nofault(&entry->id, ubuf, cnt);
 	if (len) {
 		entry->id = -1;
 		memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);

kernel/trace/trace_events_user.c

@@ -496,7 +496,7 @@ static bool user_event_enabler_queue_fault(struct user_event_mm *mm,
 {
 	struct user_event_enabler_fault *fault;
 
-	fault = kmem_cache_zalloc(fault_cache, GFP_NOWAIT | __GFP_NOWARN);
+	fault = kmem_cache_zalloc(fault_cache, GFP_NOWAIT);
 
 	if (!fault)
 		return false;

kernel/trace/trace_osnoise.c

@@ -2322,6 +2322,9 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
 	int running, err;
 	char *buf __free(kfree) = NULL;
 
+	if (count < 1)
+		return 0;
+
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

samples/ftrace/ftrace-direct-modify.c

@@ -75,8 +75,8 @@ asm (
 	CALL_DEPTH_ACCOUNT
 "	call my_direct_func1\n"
 "	leave\n"
-"	.size		my_tramp1, .-my_tramp1\n"
 	ASM_RET
+"	.size		my_tramp1, .-my_tramp1\n"
 
 "	.type		my_tramp2, @function\n"
 "	.globl		my_tramp2\n"