linux-kernel - [PATCH] objtool: continue if find_insn() fails in decode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20221208072813.25799-1-sv@linux.ibm.com>
Date:   Thu,  8 Dec 2022 12:58:13 +0530
From:   Sathvika Vasireddy <sv@...ux.ibm.com>
To:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Cc:     jpoimboe@...hat.com, peterz@...radead.org, aik@...abs.ru,
        mpe@...erman.id.au, mingo@...hat.com, christophe.leroy@...roup.eu,
        mbenes@...e.cz, npiggin@...il.com, chenzhongjin@...wei.com,
        sfr@...b.auug.org.au, naveen.n.rao@...ux.vnet.ibm.com,
        sv@...ux.ibm.com
Subject: [PATCH] objtool: continue if find_insn() fails in decode_instructions()

Currently, decode_instructions() is failing if it is not able to find
instruction, and this is happening since commit dbcdbdfdf137b4
("objtool: Rework instruction -> symbol mapping") because it is
expecting instruction for STT_NOTYPE symbols.

Due to this, the following objtool warnings are seen:
 [1] arch/powerpc/kernel/optprobes_head.o: warning: objtool: optprobe_template_end(): can't find starting instruction
 [2] arch/powerpc/kernel/kvm_emul.o: warning: objtool: kvm_template_end(): can't find starting instruction
 [3] arch/powerpc/kernel/head_64.o: warning: objtool: end_first_256B(): can't find starting instruction

The warnings are thrown because find_insn() is failing for symbols that
are at the end of the file, or at the end of the section. Given how
STT_NOTYPE symbols are currently handled in decode_instructions(),
continue if the instruction is not found, instead of throwing warning
and returning.

Signed-off-by: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
Signed-off-by: Sathvika Vasireddy <sv@...ux.ibm.com>
---
 tools/objtool/check.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4350be739f4f..bce2be5ebf36 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -430,11 +430,8 @@ static int decode_instructions(struct objtool_file *file)
 			if (func->return_thunk || func->alias != func)
 				continue;
 
-			if (!find_insn(file, sec, func->offset)) {
-				WARN("%s(): can't find starting instruction",
-				     func->name);
-				return -1;
-			}
+			if (!find_insn(file, sec, func->offset))
+				continue;
 
 			sym_for_each_insn(file, func, insn) {
 				insn->sym = func;
-- 
2.31.1