ftrace: Allow for function tracing to record init functions on boot up
Adding a hook into free_reserve_area() that informs ftrace that boot up init
text is being free, lets ftrace safely remove those init functions from its
records, which keeps ftrace from trying to modify text that no longer
exists.
Note, this still does not allow for tracing .init text of modules, as
modules require different work for freeing its init code.
Link: http://lkml.kernel.org/r/1488502497.7212.24.camel@linux.intel.com
Cc: linux-mm@kvack.org
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Requested-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6cbde31..eee82bf 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -65,6 +65,7 @@
#include <linux/page_owner.h>
#include <linux/kthread.h>
#include <linux/memcontrol.h>
+#include <linux/ftrace.h>
#include <asm/sections.h>
#include <asm/tlbflush.h>
@@ -6605,6 +6606,9 @@
void *pos;
unsigned long pages = 0;
+ /* This may be .init text, inform ftrace to remove it */
+ ftrace_free_mem(start, end);
+
start = (void *)PAGE_ALIGN((unsigned long)start);
end = (void *)((unsigned long)end & PAGE_MASK);
for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {