Files
glibc/elf/tst-ifunc-fault-dep-bindnow.c
Adhemerval Zanella 2f2e9bae40 elf: Honour skip_ifunc for cross-object IFUNC relocations [BZ #34428]
Commit 63b31c05a8 ("elf: Defer all IRELATIVE relocations until after PLT
setup") dropped the skip_ifunc argument from elf_dynamic_do_Rel, assuming
the new deferred elf_dynamic_do_Rel_irelative pass handles every relocation
that may run an IFUNC resolver.  That only holds for IFUNC symbols defined
in the object being relocated: a reference to an IFUNC in another object is
an ordinary JMP_SLOT or GLOB_DAT against an undefined symbol, and its IFUNC
nature is only known after symbol resolution inside elf_machine_rel.  Those
relocations stay in the regular pass, which no longer propagated
skip_ifunc, so __RTLD_NOIFUNC was ignored for them.

ldd -u forces non-lazy binding (GLRO(dl_lazy) = 0 for DL_DEBUG_UNUSED), so
the resolver was called and the diagnostic emitted:

  $ ldd -u /bin/ls
  /bin/ls: Relink `' with `/usr/lib64/libc.so.6' for IFUNC symbol `__mempcpy_chk'

ldd -r with LD_BIND_NOW is affected in the same way.

Restore the skip_ifunc parameter and thread it through _ELF_DYNAMIC_DO_RELOC.

This new semantic shows that ELF_DYNAMIC_RELOCATE_NOIFUNC naming is misleading
(it reads as "do not process IFUNC", yet it takes a skip_ifunc
argument). Replace it to:

  DL_RELOC_BOTH     -> DL_RELOC_ALL
  DL_RELOC_NOIFUNC  -> DL_RELOC_NORMAL
  DL_RELOC_IFUNC    -> DL_RELOC_IRELATIVE

ELF_DYNAMIC_RELOCATE_NOIFUNC and ELF_DYNAMIC_RELOCATE_IFUNC become a single
ELF_DYNAMIC_RELOCATE_PASS taking the pass as its first argument, and
ELF_DYNAMIC_DO_REL/ELF_DYNAMIC_DO_RELA take the pass instead of having three
near-identical variants each.

Checked on x86_64-linux-gnu, and built for all supported architectures.

Reviewed-by: Sam James <sam@gentoo.org>
2026-08-08 10:00:50 -03:00

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C

/* Program calling an IFUNC defined in a dependency. BIND_NOW variant.
Copyright (C) 2026 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include "tst-ifunc-fault-dep-lazy.c"