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From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	Max Reitz <mreitz@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed
Date: Tue, 16 Sep 2014 14:35:58 +0200	[thread overview]
Message-ID: <54182EAE.4000802@redhat.com> (raw)
In-Reply-To: <20140916123431.GB4886@noname.str.redhat.com>

Il 16/09/2014 14:34, Kevin Wolf ha scritto:
> I think bdrv_invalidate_cache() really needs to call bdrv_drain_all()
> before starting to reopen stuff. There could be requests in flight
> without holding the lock and if you can indeed reopen their BDS under
> their feet without breaking things (I doubt it), that would be pure
> luck.

But even that's not enough without a lock if .bdrv_invalidate_cache (the
callback) is called from a coroutine.  As soon as it yields, another
request can come in, for example from the NBD server.

Paolo

  reply	other threads:[~2014-09-16 12:36 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 [this message]
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
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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