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authorJosh Poimboeuf <jpoimboe@redhat.com>2016-08-19 06:52:57 -0500
committerIngo Molnar <mingo@kernel.org>2016-08-24 12:15:14 +0200
commit9a7c348ba6a46f6270d4fe49577649dad5664fe7 (patch)
tree747a399fc9f6f3f1e234e27a164b9bb5e6ac015a /kernel/trace
parentdaa460a88c09b26b68e8b017de589c217e901afb (diff)
ftrace: Add return address pointer to ftrace_ret_stack
Storing this value will help prevent unwinders from getting out of sync with the function graph tracer ret_stack. Now instead of needing a stateful iterator, they can compare the return address pointer to find the right ret_stack entry. Note that an array of 50 ftrace_ret_stack structs is allocated for every task. So when an arch implements this, it will add either 200 or 400 bytes of memory usage per task (depending on whether it's a 32-bit or 64-bit platform). Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_functions_graph.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 0e03ed0eac68..f7212ec643e2 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -119,7 +119,7 @@ print_graph_duration(struct trace_array *tr, unsigned long long duration,
/* Add a function return address to the trace stack on thread info.*/
int
ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
- unsigned long frame_pointer)
+ unsigned long frame_pointer, unsigned long *retp)
{
unsigned long long calltime;
int index;
@@ -174,6 +174,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
current->ret_stack[index].fp = frame_pointer;
#endif
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+ current->ret_stack[index].retp = retp;
+#endif
*depth = current->curr_ret_stack;
return 0;