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Date: Mon, 6 Jul 2020 18:00:25 -0400
From: Rich Felker <dalias@...c.org>
To: Hydro Flask <hydroflask@...mail.com>
Cc: musl@...ts.openwall.com
Subject: Re: Potential deadlock in pthread_kill()

On Tue, Jun 30, 2020 at 02:00:13PM -0700, Hydro Flask wrote:
> On 2020-06-30 12:54, Rich Felker wrote:
> >Note that for fixing this issue, it won't suffice just to make
> >pthread_kill block signals. The other places that use the killlock
> >also need to block signals, to make the lock fully AS-safe.
> 
> Rich did you see the issue I was talking about in the example in my
> previous email? Does it make sense?
> 
> I do not mind submitting a patch for this issue if you don't
> currently have the spare cycles, just let me know if we are in
> agreement in terms of understanding the issue and I can submit a
> patch that blocks "app signals" in every place that uses the
> killlock.
> 
> Probably could also remove the pthread_self() special case that you
> referenced earlier in the thread but that would be a second patch.

Yes, I see it clearly now. Sorry it took a while. I have prepared the
attached patch which I'll push soon if there are no problems.

Rich

View attachment "0001-make-thread-killlock-async-signal-safe-for-pthread_k.patch" of type "text/plain" (4225 bytes)

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