From: Carlos O'Donell <email@example.com>
To: firstname.lastname@example.org, Florian Weimer <email@example.com>,
Rich Felker <firstname.lastname@example.org>
Cc: Alexey Izbyshev <email@example.com>
Subject: Re: [musl] vfork()-based posix_spawn() has more failure modes than fork()-based one
Date: Mon, 2 May 2022 17:31:53 -0400 [thread overview]
Message-ID: <firstname.lastname@example.org> (raw)
On 5/2/22 17:25, Florian Weimer wrote:
> * Rich Felker:
>> I'm trying to understand how this comes to be. The child should
>> inherit the namespaces of the parent and thus should not be in a
>> different namespace that precludes spawn. I'm guessing this is some
>> oddity where unshare doesn't affect the process itself, only its
>> children? If so, it seems like a bug that it doesn't affect the
>> process itself after execve (after unshare(1) runs your test program),
>> but that probably can't be fixed now on the Linux side for stability
>> reasons. :(
> It's about fundamentally conflicting requirements.
> The vDSO data mapping needs to store the time offset, so it has to be
> distinct from the original namespace. vfork preserves the VM sharing.
> It's not possible to do both things at the same time.
> unshare(CLONE_NEWTIME) should have been specified to only take effect
> after execve, when the vDSO is remapped anyway.
Can we ask some kernel developers for an opinion?
next prev parent reply other threads:[~2022-05-02 21:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-02 19:26 Alexey Izbyshev
2022-05-02 20:49 ` Carlos O'Donell
2022-05-02 21:18 ` Rich Felker
2022-05-02 21:25 ` Florian Weimer
2022-05-02 21:31 ` Rich Felker
2023-02-22 22:04 ` Alexey Izbyshev
2022-05-02 21:31 ` Carlos O'Donell [this message]
2022-05-02 21:49 ` Alexey Izbyshev
2022-05-02 21:56 ` Alexey Izbyshev
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