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Subject[tip:core/urgent] objtool: Fix rare switch jump table pattern detection
Commit-ID:  56fb2d6eb63acd48b50437b415b6f7d2fcffe75d
Gitweb: http://git.kernel.org/tip/56fb2d6eb63acd48b50437b415b6f7d2fcffe75d
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Wed, 26 Oct 2016 10:34:08 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 27 Oct 2016 08:20:27 +0200

objtool: Fix rare switch jump table pattern detection

The following commit:

3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")

... improved objtool's ability to detect GCC switch statement jump
tables for GCC 6. However the check to allow short jumps with the
scanned range of instructions wasn't quite right. The pattern detection
should allow jumps to the indirect jump instruction itself.

This fixes the following warning:

drivers/infiniband/sw/rxe/rxe_comp.o: warning: objtool: rxe_completer()+0x315: sibling call from callable instruction with changed frame pointer

Reported-by: Arnd Bergmann <arnd@arndb.de>
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>
Fixes: 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
Link: http://lkml.kernel.org/r/20161026153408.2rifnw7bvoc5sex7@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
tools/objtool/builtin-check.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 4490601..e8a1f69 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -754,7 +754,7 @@ static struct rela *find_switch_table(struct objtool_file *file,
if (insn->type == INSN_JUMP_UNCONDITIONAL &&
insn->jump_dest &&
(insn->jump_dest->offset <= insn->offset ||
- insn->jump_dest->offset >= orig_insn->offset))
+ insn->jump_dest->offset > orig_insn->offset))
break;

text_rela = find_rela_by_dest_range(insn->sec, insn->offset,
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