From: Meng Xu <mengxu@cis.upenn.edu>
To: Quan Xu <quan.xu@intel.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Jan Beulich <jbeulich@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH v3 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization
Date: Thu, 10 Mar 2016 22:24:41 -0500 [thread overview]
Message-ID: <CAENZ-+=zh-fEC7kx+7S4P86izSJ+ivqnEgkaFeP1oVdajm36CQ@mail.gmail.com> (raw)
In-Reply-To: <1457529455-38314-2-git-send-email-quan.xu@intel.com>
Hi Quan,
Can I ask a dumb question?
On Wed, Mar 9, 2016 at 8:17 AM, Quan Xu <quan.xu@intel.com> wrote:
> pcidevs_lock should be held with interrupt enabled. However there remains
> an exception in AMD IOMMU code, where the lock is acquired with interrupt
> disabled. This inconsistency might lead to deadlock.
Why will this inconsistency lead to deadlock?
I understand the difference between spin_lock_irqsave(), which disable
interrupt, and spin_lock(), which allows interrupt, however, I didn't
get why misuse the spin_lock_irqsave() at the place of spin_lock()
could potentially lead to a deadlock?
Would you minding pointing me to somewhere I can find the reason or
enlighten me?
Thank you very much!
Best,
Meng
-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/
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next prev parent reply other threads:[~2016-03-11 3:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 13:17 [PATCH v3 0/2] Make the pcidevs_lock a recursive one Quan Xu
2016-03-09 13:17 ` [PATCH v3 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization Quan Xu
2016-03-09 14:59 ` Dario Faggioli
2016-03-10 6:12 ` Xu, Quan
2016-03-11 3:24 ` Meng Xu [this message]
2016-03-11 6:54 ` Xu, Quan
2016-03-11 10:35 ` Dario Faggioli
2016-03-11 12:36 ` Xu, Quan
2016-03-11 13:58 ` Dario Faggioli
2016-03-11 14:49 ` Meng Xu
2016-03-11 15:55 ` Dario Faggioli
2016-03-11 17:17 ` Meng Xu
2016-03-11 14:41 ` Meng Xu
2016-03-11 16:12 ` Dario Faggioli
2016-03-09 13:17 ` [PATCH v3 2/2] IOMMU/spinlock: Make the pcidevs_lock a recursive one Quan Xu
2016-03-09 17:45 ` Dario Faggioli
2016-03-10 1:21 ` Xu, Quan
2016-03-10 9:52 ` Jan Beulich
2016-03-10 11:27 ` Xu, Quan
2016-03-10 13:06 ` Jan Beulich
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