* [PATCH] elf: Initialize GLRO(dl_lazy) before relocating libc in dynamic startup
@ 2023-12-08 9:12 Florian Weimer
2023-12-08 13:26 ` Carlos O'Donell
0 siblings, 1 reply; 2+ messages in thread
From: Florian Weimer @ 2023-12-08 9:12 UTC (permalink / raw)
To: libc-alpha
GLRO(dl_lazy) is used to set the parameters for the early
_dl_relocate_object call, so the consider_profiling setting has to
be applied before the call.
Fixes commit 78ca44da0160a0b442f0ca1f253e3360f044b2ec ("elf: Relocate
libc.so early during startup and dlmopen (bug 31083)").
---
elf/rtld.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/elf/rtld.c b/elf/rtld.c
index f0b0f3328d..326286f3b2 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2278,14 +2278,14 @@ dl_main (const ElfW(Phdr) *phdr,
int consider_profiling = GLRO(dl_profile) != NULL;
+ /* If we are profiling we also must do lazy reloaction. */
+ GLRO(dl_lazy) |= consider_profiling;
+
if (GL(dl_ns)[LM_ID_BASE].libc_map != NULL)
_dl_relocate_object (GL(dl_ns)[LM_ID_BASE].libc_map,
GL(dl_ns)[LM_ID_BASE].libc_map->l_scope,
GLRO(dl_lazy) ? RTLD_LAZY : 0, consider_profiling);
- /* If we are profiling we also must do lazy reloaction. */
- GLRO(dl_lazy) |= consider_profiling;
-
RTLD_TIMING_VAR (start);
rtld_timer_start (&start);
{
base-commit: 958478889c6a7a12b35b857b9788b7ad8706a01e
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] elf: Initialize GLRO(dl_lazy) before relocating libc in dynamic startup
2023-12-08 9:12 [PATCH] elf: Initialize GLRO(dl_lazy) before relocating libc in dynamic startup Florian Weimer
@ 2023-12-08 13:26 ` Carlos O'Donell
0 siblings, 0 replies; 2+ messages in thread
From: Carlos O'Donell @ 2023-12-08 13:26 UTC (permalink / raw)
To: Florian Weimer, libc-alpha
On 12/8/23 04:12, Florian Weimer wrote:
> GLRO(dl_lazy) is used to set the parameters for the early
> _dl_relocate_object call, so the consider_profiling setting has to
> be applied before the call.
Yes, GLRO(dl_lazy) must be set early enough for this to work for relocation,
and it should turn on if profiling is enabled. In the old code this wasn't
a problem because we only did the relocation later in a loop, but with early
init we need to set this earlier too.
>
> Fixes commit 78ca44da0160a0b442f0ca1f253e3360f044b2ec ("elf: Relocate
> libc.so early during startup and dlmopen (bug 31083)").
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> elf/rtld.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/elf/rtld.c b/elf/rtld.c
> index f0b0f3328d..326286f3b2 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -2278,14 +2278,14 @@ dl_main (const ElfW(Phdr) *phdr,
>
> int consider_profiling = GLRO(dl_profile) != NULL;
>
> + /* If we are profiling we also must do lazy reloaction. */
> + GLRO(dl_lazy) |= consider_profiling;
OK. Agreed, this needs to move ahead of the *first* call to _dl_relocate_object().
> +
> if (GL(dl_ns)[LM_ID_BASE].libc_map != NULL)
> _dl_relocate_object (GL(dl_ns)[LM_ID_BASE].libc_map,
> GL(dl_ns)[LM_ID_BASE].libc_map->l_scope,
> GLRO(dl_lazy) ? RTLD_LAZY : 0, consider_profiling);
>
> - /* If we are profiling we also must do lazy reloaction. */
> - GLRO(dl_lazy) |= consider_profiling;
> -
OK.
> RTLD_TIMING_VAR (start);
> rtld_timer_start (&start);
> {
>
> base-commit: 958478889c6a7a12b35b857b9788b7ad8706a01e
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 2+ messages in thread
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