From: Paolo Bonzini <pbonzini@redhat.com>
To: Alex Williamson <alex.williamson@redhat.com>,
"Dong, Chuanxiao" <chuanxiao.dong@intel.com>
Cc: "kwankhede@nvidia.com" <kwankhede@nvidia.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
'Zhenyu Wang' <zhenyuw@linux.intel.com>
Subject: Re: possible recursive locking issue
Date: Fri, 7 Jul 2017 09:54:13 +0200 [thread overview]
Message-ID: <02294617-08c8-5a32-8fb1-9a8ef95ea2c3@redhat.com> (raw)
In-Reply-To: <20170706151005.41085524@w520.home>
On 06/07/2017 23:10, Alex Williamson wrote:
> vfio_unpin_pages() also takes a read-lock on
> the same. Why is this a problem? We should be able to nest
> read-locks.
rwsem is fair in that it blocks out new readers if a writer is waiting.
In this case nesting causes a deadlock, because the outer read-lock will
never be released.
Paolo
next prev parent reply other threads:[~2017-07-07 7:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-06 9:39 possible recursive locking issue Dong, Chuanxiao
2017-07-06 21:10 ` Alex Williamson
2017-07-07 2:42 ` Dong, Chuanxiao
2017-07-07 7:54 ` Paolo Bonzini [this message]
2017-07-07 15:50 ` Alex Williamson
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