From: Kevin Wolf <kwolf@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
Michael Tokarev <mjt@tls.msk.ru>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] coroutine-ucontext broken for x86-32
Date: Wed, 09 May 2012 12:11:55 +0200 [thread overview]
Message-ID: <4FAA42EB.2080407@redhat.com> (raw)
In-Reply-To: <4FA97596.4000807@siemens.com>
Am 08.05.2012 21:35, schrieb Jan Kiszka:
> Hi,
>
> I hunted down a fairly subtle corruption of the VCPU thread signal mask
> in KVM mode when using the ucontext version of coroutines:
>
> coroutine_new calls getcontext, makecontext, swapcontext. Those
> functions get/set also the signal mask of the caller. Unfortunately,
> they only use the sigprocmask syscall on i386, not the rt_sigprocmask
> version. So they do not properly save/restore the blocked RT signals,
> namely our SIG_IPI - it becomes unblocke this way.
If other coroutine backends work (sigaltstack?), we could try to detect
the situation in configure and set the right default. Not sure what the
condition is, glibc + i386?
Kevin
next prev parent reply other threads:[~2012-05-09 10:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-08 19:35 [Qemu-devel] coroutine-ucontext broken for x86-32 Jan Kiszka
2012-05-09 7:32 ` Michael Tokarev
2012-05-09 11:12 ` Jan Kiszka
2012-05-09 10:11 ` Kevin Wolf [this message]
2012-05-09 10:55 ` Jan Kiszka
2012-05-09 11:15 ` Peter Maydell
2012-05-09 11:38 ` Jan Kiszka
2012-05-09 17:17 ` Anthony Liguori
2012-05-09 17:25 ` Jan Kiszka
2012-05-09 17:31 ` Anthony Liguori
2012-05-09 18:21 ` Jan Kiszka
2012-05-09 14:37 ` Avi Kivity
2012-05-09 18:05 ` Michael Tokarev
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