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From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed
Date: Thu, 18 Sep 2014 13:26:46 +1000	[thread overview]
Message-ID: <541A50F6.4060703@ozlabs.ru> (raw)
In-Reply-To: <CAJSP0QViqHU-dtPzEe8xcF47Yj73qm0Bn48OD+wcmAwxt6jL7g@mail.gmail.com>

On 09/18/2014 01:07 AM, Stefan Hajnoczi wrote:
> On Wed, Sep 17, 2014 at 2:44 PM, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>> On 09/17/2014 07:25 PM, Paolo Bonzini wrote:
>> btw any better idea of a hack to try? Testers are pushing me - they want to
>> upgrade the broken setup and I am blocking them :) Thanks!
> 
> Paolo's qemu_co_mutex_lock(&s->lock) idea in qcow2_invalidate_cache()
> is good.  Have you tried that patch?


Yes, did not help.

> 
> I haven't checked the qcow2 code whether that works properly across
> bdrv_close() (is the lock freed?) but in principle that's how you
> protect against concurrent I/O.

I thought we have to avoid qemu_coroutine_yield() in this particular case.
I fail to see how the locks may help if we still do yeild. But the whole
thing is already way behind of my understanding :) For example - how many
BlockDriverState things are layered here? NBD -> QCOW2 -> RAW?



-- 
Alexey

  reply	other threads:[~2014-09-18  3:27 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-15 10:50 [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed Alexey Kardashevskiy
2014-09-16 12:02 ` Alexey Kardashevskiy
2014-09-16 12:10   ` Paolo Bonzini
2014-09-16 12:34     ` Kevin Wolf
2014-09-16 12:35       ` Paolo Bonzini
2014-09-16 12:52         ` Kevin Wolf
2014-09-16 12:59           ` Paolo Bonzini
2014-09-19  8:47             ` Kevin Wolf
2014-09-23  8:47               ` [Qemu-devel] [RFC PATCH] qcow2: Fix race in cache invalidation Alexey Kardashevskiy
2014-09-24  7:30                 ` Alexey Kardashevskiy
2014-09-24  9:48                 ` Kevin Wolf
2014-09-25  8:41                   ` Alexey Kardashevskiy
2014-09-25  8:57                     ` Kevin Wolf
2014-09-25  9:55                       ` Alexey Kardashevskiy
2014-09-25 10:20                         ` Kevin Wolf
2014-09-25 12:29                           ` Alexey Kardashevskiy
2014-09-25 12:39                             ` Kevin Wolf
2014-09-25 14:05                               ` Alexey Kardashevskiy
2014-09-28 11:14                                 ` Alexey Kardashevskiy
2014-09-17  6:46       ` [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed Alexey Kardashevskiy
2014-09-16 14:52     ` Alexey Kardashevskiy
2014-09-17  9:06     ` Stefan Hajnoczi
2014-09-17  9:25       ` Paolo Bonzini
2014-09-17 13:44         ` Alexey Kardashevskiy
2014-09-17 15:07           ` Stefan Hajnoczi
2014-09-18  3:26             ` Alexey Kardashevskiy [this message]
2014-09-18  9:56               ` Paolo Bonzini
2014-09-19  8:23                 ` Alexey Kardashevskiy
2014-09-17 15:04         ` Stefan Hajnoczi
2014-09-17 15:17           ` Eric Blake
2014-09-17 15:53           ` Paolo Bonzini

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