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Re: [PATCH] Reinitialize dl_load_write_lock on fork (bug 19282)
On 10/09/2017 01:06 AM, Florian Weimer wrote:
> On 10/09/2017 09:58 AM, Andreas Schwab wrote:
>> So this bug is actually INVALID but for a different reason: in a
>> multi-threaded program the forked child may only call
>> async-signal-safe functions.
>
> I think we really need to support dlopen-after-fork in multi-threaded
> processes as an extension, in the same we way need to support
> malloc-after-fork. I expect that there are quite a few programs
> which do this.
I agree with your sentiment, some of this needs to be supported, but
it will also need a new safety classification in the manual to describe
which interfaces are safe. Until we do this work, I agree with Andreas
that these uses are in theory INVALID. The same issues apply to SR-safety
which we discussed a year or two ago i.e. when is it safe for a function
to re-enter libc e.g. dlopen->malloc->dlopen (happens mostly with interposed
malloc).
--
Cheers,
Carlos.