On Okt 31 2017, Eli Zaretskii <eliz@gnu.org> wrote:
>> I also checked the following works, and seems better to me (stop having dangling pointers, instead of being
>> careful with them):
>>
>> diff --git a/src/alloc.c b/src/alloc.c
>> index da0c3ad4b3..44dfa95cf5 100644
>> --- a/src/alloc.c
>> +++ b/src/alloc.c
>> @@ -7030,8 +7030,10 @@ sweep_symbols (void)
>> {
>> if (!sym->s.gcmarkbit)
>> {
>> - if (sym->s.redirect == SYMBOL_LOCALIZED)
>> + if (sym->s.redirect == SYMBOL_LOCALIZED) {
>> xfree (SYMBOL_BLV (&sym->s));
>> + sym->s.val.blv = NULL;
>> + }
>
> That was my first attempt, but various macros like SYMBOL_BLV and
> SET_SYMBOL_BLV insist on val.blv being non-NULL.
SET_SYMBOL_BLV doesn't. And calling SYMBOL_BLV with a freed symbol is a
bug anyway.