linux-kernel - [PATCH 7/7] modpost: detect section mismatch for R_ARM

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Message-Id: <20230601121001.1071533-8-masahiroy@kernel.org>
Date:   Thu,  1 Jun 2023 21:10:01 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     linux-kbuild@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        Russell King <linux@...linux.org.uk>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nicolas Schier <nicolas@...sle.eu>
Subject: [PATCH 7/7] modpost: detect section mismatch for R_ARM_REL32

For ARM, modpost fails to detect some types of section mismatches.

  [test code]

    .section .init.data,"aw"
    bar:
            .long 0

    .section .data,"aw"
    .globl foo
    foo:
            .long bar - .

It is apparently a bad reference, but modpost does not report anything.

The test code above produces the following relocations.

  Relocation section '.rel.data' at offset 0xe8 contains 1 entry:
   Offset     Info    Type            Sym.Value  Sym. Name
  00000000  00000403 R_ARM_REL32       00000000   .init.data

Currently, R_ARM_REL32 is just skipped.

Handle it like R_ARM_ABS32.

Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
---

 scripts/mod/modpost.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 55d142bb000b..9f0c87064ca5 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1281,6 +1281,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
 
 	switch (r_typ) {
 	case R_ARM_ABS32:
+	case R_ARM_REL32:
 		inst = TO_NATIVE(*(uint32_t *)loc);
 		r->r_addend = inst + sym->st_value;
 		break;
-- 
2.39.2