Commit 0ea5ad86 authored Jun 15, 2016 by Josh Poimboeuf Committed by Ingo Molnar Jul 10, 2016

objtool: Fix STACK_FRAME_NON_STANDARD macro checking for function symbols



Mathieu Desnoyers reported that the STACK_FRAME_NON_STANDARD macro
wasn't working with the lttng_filter_interpret_bytecode() function in
the lttng-modules code.

Usually the relocation created by STACK_FRAME_NON_STANDARD creates a
reference to a section symbol like this:

  Offset              Type            Value               Addend Name
  000000000000000000  X86_64_64       000000000000000000   +3136 .text

But in this case it created a reference to a function symbol:

  Offset              Type            Value               Addend Name
  000000000000000000  X86_64_64       0x00000000000003a0      +0 lttng_filter_interpret_bytecode

To be honest I have no idea what causes gcc to decide to do one over the
other.  But both are valid ELF, so add support for the function symbol.

Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: lttng-dev@lists.lttng.org
Link: http://lkml.kernel.org/r/9cee42843bc6d94e990a152e4e0319cfdf6756ef.1466023450.git.jpoimboe@redhat.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent ee40fb29

tools/objtool/builtin-check.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -122,10 +122,14 @@ static bool ignore_func(struct objtool_file file, struct symbol func)

		/* check for STACK_FRAME_NON_STANDARD */
		if (file->whitelist && file->whitelist->rela)
		list_for_each_entry(rela, &file->whitelist->rela->rela_list, list)
		if (rela->sym->sec == func->sec &&
		list_for_each_entry(rela, &file->whitelist->rela->rela_list, list) {
		if (rela->sym->type == STT_SECTION &&
		rela->sym->sec == func->sec &&
		rela->addend == func->offset)
		return true;
		if (rela->sym->type == STT_FUNC && rela->sym == func)
		return true;
		}

		/* check if it has a context switching instruction */
		func_for_each_insn(file, func, insn)