From: Paolo Bonzini <pbonzini@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
"Shergill, Gurinder" <gurinder.shergill@hp.com>,
"Vinod, Chegu" <chegu_vinod@hp.com>,
qemu-devel@nongnu.org, Luiz Capitulino <lcapitulino@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 1/2] iothread: stash thread ID away
Date: Tue, 25 Feb 2014 17:27:08 +0100 [thread overview]
Message-ID: <530CC45C.8010604@redhat.com> (raw)
In-Reply-To: <20140225161738.GD2374@stefanha-thinkpad.redhat.com>
Il 25/02/2014 17:17, Stefan Hajnoczi ha scritto:
> For the default mutex type (PTHREAD_MUTEX_TIMED_NP) glibc looks safe to
> me. The other mutex types are trickier and I haven't audited them.
It also depends on the low-level lock implementation. I looked at the C
one and it's not safe, the x86-optimized one is hard to follow.
I think I was looking at a different race, namely cases where the
locking thread uses a fast path, while the unlocking thread plays it
safe and uses the slow path instead. Then the slow path can run
"asynchronously" from the locking thread, and the locking thread has
time to unlock and destroy the mutex. See the other message.
Paolo
next prev parent reply other threads:[~2014-02-25 16:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-21 14:51 [Qemu-devel] [PATCH 0/2] dataplane: add query-iothreads QMP command Stefan Hajnoczi
2014-02-21 14:51 ` [Qemu-devel] [PATCH 1/2] iothread: stash thread ID away Stefan Hajnoczi
2014-02-21 15:18 ` Paolo Bonzini
2014-02-24 15:53 ` Stefan Hajnoczi
2014-02-24 16:48 ` Paolo Bonzini
2014-02-25 15:42 ` Stefan Hajnoczi
2014-02-25 16:10 ` Paolo Bonzini
2014-02-25 16:17 ` Stefan Hajnoczi
2014-02-25 16:27 ` Paolo Bonzini [this message]
2014-02-21 14:51 ` [Qemu-devel] [PATCH 2/2] qmp: add query-iothreads command Stefan Hajnoczi
2014-02-21 15:27 ` Eric Blake
2014-02-24 15:54 ` Stefan Hajnoczi
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