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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Miroslav Benes <mbenes@suse.cz>,
	Julien Thierry <jthierry@redhat.com>
Subject: [PATCH 4/5] objtool: Fix switch table detection in .text.unlikely
Date: Wed,  1 Apr 2020 13:23:28 -0500	[thread overview]
Message-ID: <157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1585761021.git.jpoimboe@redhat.com>

If a switch jump table's indirect branch is in a ".cold" subfunction in
.text.unlikely, objtool doesn't detect it, and instead prints a false
warning:

  drivers/media/v4l2-core/v4l2-ioctl.o: warning: objtool: v4l_print_format.cold()+0xd6: sibling call from callable instruction with modified stack frame
  drivers/hwmon/max6650.o: warning: objtool: max6650_probe.cold()+0xa5: sibling call from callable instruction with modified stack frame
  drivers/media/dvb-frontends/drxk_hard.o: warning: objtool: init_drxk.cold()+0x16f: sibling call from callable instruction with modified stack frame

Fix it by comparing the function, instead of the section and offset.

Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/check.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index aaec5e1277ea..c681a26c25ac 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1068,10 +1068,7 @@ static struct rela *find_jump_table(struct objtool_file *file,
 	 * it.
 	 */
 	for (;
-	     &insn->list != &file->insn_list &&
-	     insn->sec == func->sec &&
-	     insn->offset >= func->offset;
-
+	     &insn->list != &file->insn_list && insn->func && insn->func->pfunc == func;
 	     insn = insn->first_jump_src ?: list_prev_entry(insn, list)) {
 
 		if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)
-- 
2.21.1


  parent reply	other threads:[~2020-04-01 18:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-01 18:23 [PATCH 0/5] objtool fixes Josh Poimboeuf
2020-04-01 18:23 ` [PATCH 1/5] objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings Josh Poimboeuf
2020-04-02  7:30   ` Kees Cook
2020-04-14 10:34   ` [tip: x86/urgent] " tip-bot2 for Josh Poimboeuf
2020-04-01 18:23 ` [PATCH 2/5] objtool: Support Clang non-section symbols in ORC dump Josh Poimboeuf
2020-04-14 10:34   ` [tip: x86/urgent] " tip-bot2 for Josh Poimboeuf
2020-04-01 18:23 ` [PATCH 3/5] objtool: Support Clang non-section symbols in ORC generation Josh Poimboeuf
2020-04-01 18:49   ` Peter Zijlstra
2020-04-01 19:05     ` Josh Poimboeuf
2020-04-01 19:08       ` Josh Poimboeuf
2020-04-03  8:58   ` Miroslav Benes
2020-04-03 14:58     ` Josh Poimboeuf
2020-04-14 10:34   ` [tip: x86/urgent] " tip-bot2 for Josh Poimboeuf
2020-04-01 18:23 ` Josh Poimboeuf [this message]
2020-04-14 10:34   ` [tip: x86/urgent] objtool: Fix switch table detection in .text.unlikely tip-bot2 for Josh Poimboeuf
2020-04-01 18:23 ` [PATCH 5/5] objtool: Make BP scratch register warning more robust Josh Poimboeuf
2020-04-14 10:34   ` [tip: x86/urgent] " tip-bot2 for Josh Poimboeuf
2020-04-02 14:28 ` [PATCH 0/5] objtool fixes Peter Zijlstra
2020-04-03  9:00 ` Miroslav Benes
2020-04-09 13:53 ` Josh Poimboeuf

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