https://sourceware.org/bugzilla/show_bug.cgi?id=33209
Florian Weimer <fweimer at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |fweimer at redhat dot com
--- Comment #1 from Florian Weimer <fweimer at redhat dot com> ---
Apparently, it's deliberate:
static void
elf_x86_64_add_glibc_version_dependency
(struct elf_find_verdep_info *rinfo)
{
unsigned int i = 0;
const char *version[3] = { NULL, NULL, NULL };
struct elf_x86_link_hash_table *htab;
if (rinfo->info->enable_dt_relr)
{
version[i] = "GLIBC_ABI_DT_RELR";
i++;
}
htab = elf_x86_hash_table (rinfo->info, X86_64_ELF_DATA);
if (htab != NULL && htab->params->mark_plt)
{
version[i] = "GLIBC_2.36";
i++;
}
if (i != 0)
_bfd_elf_link_add_glibc_version_dependency (rinfo, version);
}
Sneaky.
commit 9167304255940e29423517f63d11bdd968d7685e
Author: H.J. Lu <[email protected]>
Date: Fri May 19 15:11:51 2023 -0700
elf: Add elf_backend_add_glibc_version_dependency
When -z mark-plt is used to add DT_X86_64_PLT, DT_X86_64_PLTSZ and
DT_X86_64_PLTENT, the r_addend field of the R_X86_64_JUMP_SLOT relocation
stores the offset of the indirect branch instruction. However, glibc
versions which don't have this commit in glibc 2.36:
commit f8587a61892cbafd98ce599131bf4f103466f084
Author: H.J. Lu <[email protected]>
Date: Fri May 20 19:21:48 2022 -0700
x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
According to x86-64 psABI, r_addend should be ignored for
R_X86_64_GLOB_DAT
and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0,
we
can ignore their r_addends.
Reviewed-by: Fangrui Song <[email protected]>
won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
Although this commit has been backported to glibc 2.33/2.34/2.35 release
branches, it is safer to require glibc 2.36 for such binaries.
Extend the glibc version dependency of GLIBC_ABI_DT_RELR for DT_RELR to
also add GLIBC_2.36 version dependency for -z mark-plt on the shared C
library if it provides a GLIBC_2.XX symbol version.
* elflink.c (elf_find_verdep_info): Moved to ...
* elf-bfd.h (elf_find_verdep_info): Here.
(elf_backend_data): Add elf_backend_add_glibc_version_dependency.
(_bfd_elf_link_add_glibc_version_dependency): New function.
(_bfd_elf_link_add_dt_relr_dependency): Likewise.
* elf64-x86-64.c (elf_x86_64_add_glibc_version_dependency):
Likewise.
(elf_backend_add_glibc_version_dependency): New.
* elflink.c (elf_link_add_dt_relr_dependency): Renamed to ...
(elf_link_add_glibc_verneed): This. Modified to support other
glibc dependencies.
(_bfd_elf_link_add_glibc_version_dependency): Likewise.
(_bfd_elf_link_add_dt_relr_dependency): Likewise.
(bfd_elf_size_dynamic_sections): Call
elf_backend_add_glibc_version_dependency instead of
elf_link_add_dt_relr_dependency.
* elfxx-target.h (elf_backend_add_glibc_version_dependency): New.
(elfNN_bed): Add elf_backend_add_glibc_version_dependency.
ld/
* testsuite/ld-x86-64/mark-plt-1a.rd: New file.
* testsuite/ld-x86-64/mark-plt-1b.rd: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run -z mark-plt test for
GLIBC_2.36 dependency.
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