Fix SPARC64 handling of R_SPARC_H34 (bug 24231)
Commit Message
Building glibc with -Wextra shows a -Wimplicit-fallthrough warning for
SPARC64 that appears to be a real bug in glibc. The dynamic linker
handling of R_SPARC_H34 falls through to that of R_SPARC_H44, which in
the case of this code is nonsensical (it means the value computed for
R_SPARC_H34 gets overwritten by one computed with the different logic
for R_SPARC_H44). Thus, this patch adds the missing break there.
Note: I do not have a testcase to demonstrate this bug.
Tested with build-many-glibcs.py.
2019-02-18 Joseph Myers <joseph@codesourcery.com>
[BZ #24231]
* sysdeps/sparc/sparc64/dl-machine.h (elf_machine_rela): Add break
after R_SPARC_H34 case.
Comments
On 18/02/2019 15:41, Joseph Myers wrote:
> Building glibc with -Wextra shows a -Wimplicit-fallthrough warning for
> SPARC64 that appears to be a real bug in glibc. The dynamic linker
> handling of R_SPARC_H34 falls through to that of R_SPARC_H44, which in
> the case of this code is nonsensical (it means the value computed for
> R_SPARC_H34 gets overwritten by one computed with the different logic
> for R_SPARC_H44). Thus, this patch adds the missing break there.
> Note: I do not have a testcase to demonstrate this bug.
>
> Tested with build-many-glibcs.py.
Look obvious enough to me.
>
> 2019-02-18 Joseph Myers <joseph@codesourcery.com>
>
> [BZ #24231]
> * sysdeps/sparc/sparc64/dl-machine.h (elf_machine_rela): Add break
> after R_SPARC_H34 case.
>
> diff --git a/sysdeps/sparc/sparc64/dl-machine.h b/sysdeps/sparc/sparc64/dl-machine.h
> index 2fb207dc2d..14930890e3 100644
> --- a/sysdeps/sparc/sparc64/dl-machine.h
> +++ b/sysdeps/sparc/sparc64/dl-machine.h
> @@ -573,6 +573,7 @@ elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
> *(unsigned int *) reloc_addr =
> ((*(unsigned int *)reloc_addr & 0xffc00000) |
> ((value >> 12) & 0x3fffff));
> + break;
>
> /* MEDMID code model relocs */
> case R_SPARC_H44:
>
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Mon, 18 Feb 2019 17:18:24 -0300
>
>
> On 18/02/2019 15:41, Joseph Myers wrote:
>> Building glibc with -Wextra shows a -Wimplicit-fallthrough warning for
>> SPARC64 that appears to be a real bug in glibc. The dynamic linker
>> handling of R_SPARC_H34 falls through to that of R_SPARC_H44, which in
>> the case of this code is nonsensical (it means the value computed for
>> R_SPARC_H34 gets overwritten by one computed with the different logic
>> for R_SPARC_H44). Thus, this patch adds the missing break there.
>> Note: I do not have a testcase to demonstrate this bug.
>>
>> Tested with build-many-glibcs.py.
>
> Look obvious enough to me.
Looks good here too.
@@ -573,6 +573,7 @@ elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
*(unsigned int *) reloc_addr =
((*(unsigned int *)reloc_addr & 0xffc00000) |
((value >> 12) & 0x3fffff));
+ break;
/* MEDMID code model relocs */
case R_SPARC_H44: