Re: [Emacs-diffs] master 8ba156f: Attempt to avoid crashes in plist-member

[David Kastrup]

Eli Zaretskii <address@hidden> writes:

>> From: David Kastrup <address@hidden>
>> Cc: Paul Eggert <address@hidden>, address@hidden,
>> address@hidden
>> Date: Tue, 13 Oct 2015 17:08:52 +0200
>> 
>> CONSP only checks some bits on a pointer.  It does not verify that
>> the pointer can be dereferenced into an existing cons cell.  So there is
>> absolutely no need to modify anything between having a true CONSP test
>> and a crashing XCAR.
>
> Yes, well...  I didn't have such a serious calamity in mind.

Shrug.  An accidental collection when the value is currently in a local
variable clearly having to end up in the stack frame seems less likely
to me than an accidental collection at a time when the value was not in
active use but likely only stored in some heap data structure.  Who
marks the structures in those?

If the calamity is indeed premature collection rather than a random
value that was never valid to start with.

-- 
David Kastrup