From: "Jan Beulich" <JBeulich@suse.com>
To: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Quan Xu <quan.xu@intel.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH v2 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization.
Date: Wed, 09 Mar 2016 06:55:51 -0700 [thread overview]
Message-ID: <56E0397702000078000DADA4@prv-mh.provo.novell.com> (raw)
In-Reply-To: <945CA011AD5F084CBEA3E851C0AB28894B85F359@SHSMSX101.ccr.corp.intel.com>
>>> On 09.03.16 at 14:46, <quan.xu@intel.com> wrote:
> Now I am still not clear for this point- "this inconsistency might lead to
> deadlock".
> I think it is similar to 'mixing interrupt disabled and enabled spinlocks is
> something we disallow'.
> I hope you can give me an example about how to lead to deadlock.
The implication from disabling interrupts while acquiring a lock
is that the lock is also being acquired by some interrupt
handler. If you mix acquire types, the one not disabling
interrupts is prone to be interrupted, and the interrupt trying
to get hold of the lock the same CPU already owns.
Jan
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next prev parent reply other threads:[~2016-03-09 13:55 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 3:08 [PATCH v2 0/2] Make the pcidevs_lock a recursive one Quan Xu
2016-03-09 3:08 ` [PATCH v2 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization Quan Xu
2016-03-09 5:19 ` Tian, Kevin
2016-03-09 7:31 ` Xu, Quan
2016-03-09 10:09 ` Jan Beulich
2016-03-09 10:24 ` Dario Faggioli
2016-03-09 12:52 ` Xu, Quan
2016-03-09 13:19 ` Dario Faggioli
2016-03-09 13:46 ` Xu, Quan
2016-03-09 13:55 ` Jan Beulich [this message]
2016-03-09 14:45 ` Dario Faggioli
2016-03-10 5:36 ` Xu, Quan
2016-03-10 3:21 ` Xu, Quan
2016-03-09 3:08 ` [PATCH v2 2/2] IOMMU/spinlock: Make the pcidevs_lock a recursive one Quan Xu
2016-03-09 5:21 ` Tian, Kevin
2016-03-09 5:50 ` Xu, Quan
2016-03-09 12:18 [PATCH v2 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization Xu, Quan
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