tracing: Remove outdated comment in stack handling

This comment describes the behaviour before commit 2a820bf74918
("tracing: Use percpu stack trace buffer more intelligently").  Since
that commit, interrupts and NMIs do use the per-cpu stacks so the
comment is no longer correct.  Remove it.

(Note that the FTRACE_STACK_SIZE mentioned in the comment has never
existed, it probably should have said FTRACE_STACK_ENTRIES.)

Link: https://lkml.kernel.org/r/20200727092840.18659-1-vincent.whitchurch@axis.com
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4aab712..dbcacdd 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2930,12 +2930,6 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer,
                skip++;
 #endif
 
-       /*
-        * Since events can happen in NMIs there's no safe way to
-        * use the per cpu ftrace_stacks. We reserve it and if an interrupt
-        * or NMI comes in, it will just have to use the default
-        * FTRACE_STACK_SIZE.
-        */
        preempt_disable_notrace();
 
        stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;