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

[Andreas Schwab]

Eli Zaretskii <address@hidden> writes:

>> From: Stefan Monnier <address@hidden>
>> Cc: Eli Zaretskii <address@hidden>
>> Date: Mon, 12 Oct 2015 21:07:00 -0400
>> 
>> >     Attempt to avoid crashes in plist-member
>>     
>> >     * src/fns.c (Fplist_member): Don't call QUIT between a CONSP test
>> >     and a call to XCDR.  (Bug#21655)
>> 
>> I have no objection to the patch itself, but I must say that I wonder
>> how it can avoid crashes.  IOW why would calling QUIT between a CONSP test
>> and a call to XCDR be dangerous?
>
> QUIT could call some Lisp.
>
> How else would you explain a segfault in that loop?

The only chance I see if garbage collection mistakenly collects the
referenced cell.  But that wouldn't be cured by the change.

Andreas.

-- 
Andreas Schwab, SUSE Labs, address@hidden
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