From: Paul Mackerras <paulus@samba.org>
To: Liu Ping Fan <kernelfans@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, Alexander Graf <agraf@suse.de>,
kvm-ppc@vger.kernel.org
Subject: Re: [PATCH 2/3] powerpc/kvm: fix rare but potential deadlock scene
Date: Wed, 6 Nov 2013 16:04:18 +1100 [thread overview]
Message-ID: <20131106050418.GD14842@drongo> (raw)
In-Reply-To: <1383637364-14691-2-git-send-email-pingfank@linux.vnet.ibm.com>
On Tue, Nov 05, 2013 at 03:42:43PM +0800, Liu Ping Fan wrote:
> Since kvmppc_hv_find_lock_hpte() is called from both virtmode and
> realmode, so it can trigger the deadlock.
Good catch, we should have preemption disabled while ever we have a
HPTE locked.
> @@ -474,8 +474,10 @@ static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
> }
>
> /* Find the HPTE in the hash table */
> + preempt_disable();
> index = kvmppc_hv_find_lock_hpte(kvm, eaddr, slb_v,
> HPTE_V_VALID | HPTE_V_ABSENT);
> + preempt_enable();
Which means we need to add the preempt_enable after unlocking the
HPTE, not here.
Regards,
Paul.
next prev parent reply other threads:[~2013-11-06 5:04 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-05 7:42 [PATCH 1/3] powerpc/kvm: simplify the entering logic for secondary thread Liu Ping Fan
2013-11-05 7:42 ` [PATCH 2/3] powerpc/kvm: fix rare but potential deadlock scene Liu Ping Fan
2013-11-06 5:04 ` Paul Mackerras [this message]
2013-11-06 6:02 ` Liu ping fan
2013-11-06 11:18 ` Paul Mackerras
2013-11-07 2:36 ` Liu ping fan
2013-11-05 7:42 ` [PATCH 3/3] powerpc/kvm: remove redundant assignment Liu Ping Fan
2013-11-06 5:04 ` Paul Mackerras
2013-11-06 11:24 ` Alexander Graf
2013-11-06 19:58 ` Benjamin Herrenschmidt
2013-11-07 7:52 ` Alexander Graf
2013-11-07 7:55 ` Benjamin Herrenschmidt
2013-11-07 8:14 ` Alexander Graf
2013-11-07 8:36 ` Benjamin Herrenschmidt
2013-11-06 5:01 ` [PATCH 1/3] powerpc/kvm: simplify the entering logic for secondary thread Paul Mackerras
2013-11-06 7:26 ` Liu ping fan
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