This is a note to let you know that I've just added the patch titled
objtool: Fix switch table detection in .text.unlikely
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
objtool-fix-switch-table-detection-in-.text.unlikely.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b401efc120a399dfda1f4d2858a4de365c9b08ef Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Date: Wed, 1 Apr 2020 13:23:28 -0500
Subject: objtool: Fix switch table detection in .text.unlikely
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
commit b401efc120a399dfda1f4d2858a4de365c9b08ef upstream.
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@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/objtool/check.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -914,10 +914,7 @@ static struct rela *find_switch_table(st
* 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)
Patches currently in stable-queue which might be from jpoimboe@xxxxxxxxxx are
queue-4.9/objtool-fix-switch-table-detection-in-.text.unlikely.patch
