ftrace: Add return address pointer to ftrace_ret_stack
authorJosh Poimboeuf <jpoimboe@redhat.com>
Fri, 19 Aug 2016 11:52:57 +0000 (06:52 -0500)
committerIngo Molnar <mingo@kernel.org>
Wed, 24 Aug 2016 10:15:14 +0000 (12:15 +0200)
commit9a7c348ba6a46f6270d4fe49577649dad5664fe7
tree747a399fc9f6f3f1e234e27a164b9bb5e6ac015a
parentdaa460a88c09b26b68e8b017de589c217e901afb
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>
15 files changed:
Documentation/trace/ftrace-design.txt
arch/arm/kernel/ftrace.c
arch/arm64/kernel/ftrace.c
arch/blackfin/kernel/ftrace.c
arch/microblaze/kernel/ftrace.c
arch/mips/kernel/ftrace.c
arch/parisc/kernel/ftrace.c
arch/powerpc/kernel/ftrace.c
arch/s390/kernel/ftrace.c
arch/sh/kernel/ftrace.c
arch/sparc/kernel/ftrace.c
arch/tile/kernel/ftrace.c
arch/x86/kernel/ftrace.c
include/linux/ftrace.h
kernel/trace/trace_functions_graph.c