Re: [PATCH] elf: Make more functions available for binding during dlclose (bug 30425)

[Andreas Schwab <schwab@suse.de>]

On Mai 22 2023, Florian Weimer via Libc-alpha wrote:

> diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
> index 05f36a2507..c709ac4d33 100644
> --- a/elf/dl-lookup.c
> +++ b/elf/dl-lookup.c
> @@ -366,8 +366,13 @@ do_lookup_x (const char *undef_name, unsigned int new_hash,
>        if ((type_class & ELF_RTYPE_CLASS_COPY) && map->l_type == lt_executable)
>  	continue;
>  
> -      /* Do not look into objects which are going to be removed.  */
> -      if (map->l_removed)
> +      /* Do not look into objects which are going to be removed,
> +	 except when the referencing object itself is being removed.
> +	 The second part covers the situation when an object lazily
> +	 binds to another object while running its destructor, but the
> +	 destructor of the other object has already run, so that
> +	 dlclose has already set l_removed.  */

But if the destructor has been run already, it is no longer safe to call
functions from that object.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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