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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH] objtool: fix rare switch jump table pattern detection
Date: Wed, 26 Oct 2016 10:34:08 -0500	[thread overview]
Message-ID: <20161026153408.2rifnw7bvoc5sex7@treble> (raw)
In-Reply-To: <3971280.DNU2zoGODW@wuerfel>

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>
Fixes: 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 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,
-- 
2.7.4

  parent reply	other threads:[~2016-10-26 15:34 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-13 21:22 [PATCH 0/2] objtool: a couple of minor fixes Josh Poimboeuf
2016-10-13 21:22 ` [PATCH 1/2] objtool: improve rare switch jump table pattern detection Josh Poimboeuf
2016-10-16 11:18   ` [tip:core/urgent] objtool: Improve " tip-bot for Josh Poimboeuf
2016-10-13 21:22 ` [PATCH 2/2] objtool: skip all "unreachable instruction" warnings for gcov kernels Josh Poimboeuf
2016-10-16 11:18   ` [tip:core/urgent] objtool: Skip " tip-bot for Josh Poimboeuf
2016-10-26  7:58 ` [PATCH 0/2] objtool: a couple of minor fixes Arnd Bergmann
2016-10-26  9:16   ` Arnd Bergmann
2016-10-26 12:37   ` Josh Poimboeuf
2016-10-26 12:43     ` Josh Poimboeuf
2016-10-26 13:18       ` Josh Poimboeuf
2016-10-26 15:34   ` Josh Poimboeuf [this message]
2016-10-26 16:03     ` [PATCH] objtool: fix rare switch jump table pattern detection Arnd Bergmann
2016-10-26 16:45       ` Josh Poimboeuf
2016-10-27  7:37     ` [tip:core/urgent] objtool: Fix " tip-bot for Josh Poimboeuf

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