[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH 1/2] iothread: stash thread ID away

From: Paolo Bonzini
Subject: Re: [Qemu-devel] [PATCH 1/2] iothread: stash thread ID away
Date: Mon, 24 Feb 2014 17:48:13 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0

Il 24/02/2014 16:53, Stefan Hajnoczi ha scritto:
> >+    qemu_cond_destroy(&init_info.init_done_cond);
> >+    qemu_mutex_destroy(&init_info.init_done_lock);
> Destroying the mutex here is racy.  You need to keep it until the
> iothread is destroyed.
I don't think so:

qemu_cond_signal() is called with the mutex held.  Therefore, our
qemu_cond_wait() followed by qemu_mutex_unlock() will only complete once
the thread has released the mutex.

The thread will never touch the mutex again so it is safe to destroy it.
There is no race condition.

Could qemu_mutex_destroy run while the other thread has already released the main thread, but before it returns? As far as I know, the only time when it is safe to destroy the "last" synchronization object (in this case the mutex is the last, the condvar is not) is after pthread_join.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]