Re: [PATCH] DWZ aborted "write_types: Assertion `ref && ref->die_dup == NULL'"

[Mark Wielaard <mark@klomp.org>]

Hi Alok,

On Fri, 2021-02-05 at 06:09 +0000, Sharma, Alok Kumar via Dwz wrote:
> Would you please review the attached patch containing modification of
> assert condition.
> It was required to fix an abort which seem to be incorrect.
> 
> There is an assert condition as "ref && ref->die_dup == NULL".
> As per definition of "struct dw_die", the structure fields starting
> from 'die_dup' are present only if 'die_toplevel' is 1. In line with
> this at multiple places in code, full/paritial memory is allocated for
> pointer of type dw_die.
> Ex.  die = pool_alloc (dw_die, offsetof (struct dw_die, die_dup));
> Due to this, since memory is not allocated for field die_dup onwards,
> it may contain junk values. Macro 'die_safe_dupe' must be used in place
> of directly accessing 'die_dup' field whenever required.
> 
>       * dwz.c (write_types): Use 'die_safe_dup' to access field 'die_dup'.

I think you analysis and the code fix are correct. Thanks.

This was probably missed before because -fdebug-types-section isn't the
default, so we are not seeing many DWARF files with debug types.

Do you have an example where this triggers?

Thanks,

Mark