From: Peter Maydell <peter.maydell@linaro.org>
To: Max Filippov <jcmvbkbc@gmail.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>,
Laurent Vivier <laurent@vivier.eu>
Subject: Re: [Qemu-devel] [PATCH] linux-user: do setrlimit selectively
Date: Tue, 4 Sep 2018 23:55:15 +0100 [thread overview]
Message-ID: <CAFEAcA9LtXdP7MYEf4X3SkJjnpQaSDRNaFh3rYVcWeaUgKBoew@mail.gmail.com> (raw)
In-Reply-To: <CAMo8Bf+bV9wAX_ctyy2pftLnyb+_7ukiVkD5sEENX94=nQmMfw@mail.gmail.com>
On 4 September 2018 at 23:26, Max Filippov <jcmvbkbc@gmail.com> wrote:
> On Tue, Sep 4, 2018 at 3:10 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
>> On 4 September 2018 at 23:02, Max Filippov <jcmvbkbc@gmail.com> wrote:
>> You could make a case for always ignoring setrlimit calls: if we
>> ever hit the limit it's as likely to be by failing a QEMU internal
>> allocation as a guest one, so not to imposing the limit at all
>> would avoid QEMU failing then. But that would apply in both the
>> 32-on-64 and also 32-on-32 and 64-on-64 cases too.
>
> That's what I did initially, but it feels somewhat unsafe in 64-on-64 case.
> My expectation is that limits set by 64-bit guest should be somewhat
> suitable for the 64-bit host, is it wrong?
It doesn't matter what the limit the guest sets is -- the
problem is that if we hit it then chances are good it'll cause
a QEMU allocation to fail and then we'll deadlock. The limit
might be entirely reasonable for the guest program (which
presumably has a plan for handling the failure) but QEMU
itself can't cope with hitting the limit.
https://bugs.launchpad.net/qemu/+bug/1163034 is the bug I
mentioned in my earlier email, by the way.
thanks
-- PMM
next prev parent reply other threads:[~2018-09-04 22:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-04 21:00 [Qemu-devel] [PATCH] linux-user: do setrlimit selectively Max Filippov
2018-09-04 21:13 ` Peter Maydell
2018-09-04 22:02 ` Max Filippov
2018-09-04 22:10 ` Peter Maydell
2018-09-04 22:26 ` Max Filippov
2018-09-04 22:55 ` Peter Maydell [this message]
2018-09-05 0:08 ` Max Filippov
2018-09-05 1:40 ` Peter Maydell
2018-09-05 1:51 ` Max Filippov
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