Messages in this thread Patch in this message | | | Date | Wed, 9 Mar 2016 03:43:55 -0800 | From | tip-bot for Josh Poimboeuf <> | Subject | [tip:core/objtool] objtool: Fix false positive warnings related to sibling calls |
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Commit-ID: d8d1b2cb58540b0cf572be4715167c473193888e Gitweb: http://git.kernel.org/tip/d8d1b2cb58540b0cf572be4715167c473193888e Author: Josh Poimboeuf <jpoimboe@redhat.com> AuthorDate: Wed, 9 Mar 2016 00:06:54 -0600 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 9 Mar 2016 10:48:08 +0100
objtool: Fix false positive warnings related to sibling calls
With some configs [1], objtool prints a bunch of false positive warnings like:
arch/x86/events/core.o: warning: objtool: x86_del_exclusive()+0x0: frame pointer state mismatch
For some reason this config has a bunch of sibling calls. When objtool follows a sibling call jump, it attempts to compare the frame pointer state. But it also accidentally compares the FENTRY state, resulting in a false positive warning.
[1] https://lkml.kernel.org/r/20160308154909.GA20956@gmail.com
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris J Arges <chris.j.arges@canonical.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Pedro Alves <palves@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/382de77ccaaa8cd79b27a155c3d109ebd4ce0219.1457502970.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- tools/objtool/builtin-check.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 51da270..fe24804 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -729,6 +729,11 @@ static bool has_valid_stack_frame(struct instruction *insn) (insn->state & STATE_FP_SETUP); } +static unsigned int frame_state(unsigned long state) +{ + return (state & (STATE_FP_SAVED | STATE_FP_SETUP)); +} + /* * Follow the branch starting at the given instruction, and recursively follow * any other branches (jumps). Meanwhile, track the frame pointer state at @@ -756,7 +761,7 @@ static int validate_branch(struct objtool_file *file, while (1) { if (insn->visited) { - if (insn->state != state) { + if (frame_state(insn->state) != frame_state(state)) { WARN_FUNC("frame pointer state mismatch", sec, insn->offset); warnings++;
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