From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
kvm@vger.kernel.org
Subject: Re: [BUG] kvm: dereference srcu-protected pointer without srcu_read_lock() held
Date: Mon, 19 Apr 2010 22:45:04 -0300 [thread overview]
Message-ID: <20100420014504.GB17981@amt.cnet> (raw)
In-Reply-To: <4BCC2B9D.8050008@redhat.com>
On Mon, Apr 19, 2010 at 01:08:29PM +0300, Avi Kivity wrote:
> On 04/19/2010 12:58 PM, Lai Jiangshan wrote:
> >Applied the patch I just sent and let CONFIG_PROVE_RCU=y,
> >we can got the following dmesg. And we found that it is
> >because some codes in KVM dereferences srcu-protected pointer without
> >srcu_read_lock() held or update-side lock held.
> >
> >It is not hard to fix, the problem is that:
> >Where is the most proper place to put a srcu_read_lock()?
> >
> >I can not determine the answer, so I report this bug
> >instead of fixing it.
> >
>
> I think the else branch in complete_pio() should work. Marcelo?
>
> Longer term I'd like to see the lock taken at the high levels
> (ioctls, in virt/kvm) and dropped only for guest entry and when we
> explicitly sleep (hlt emulation).
>
> Note: complete_pio() is gone in the current code.
Yes, this was fixed by 7fb2ea1e6.
next prev parent reply other threads:[~2010-04-20 1:45 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-19 9:41 [PATCH] kvm: use the correct RCU API Lai Jiangshan
2010-04-19 9:49 ` Avi Kivity
2010-04-19 23:35 ` Paul E. McKenney
2010-04-20 2:09 ` Lai Jiangshan
2010-04-20 18:42 ` Paul E. McKenney
2010-04-19 9:58 ` [BUG] kvm: dereference srcu-protected pointer without srcu_read_lock() held Lai Jiangshan
2010-04-19 10:08 ` Avi Kivity
2010-04-20 1:45 ` Marcelo Tosatti [this message]
2010-04-20 6:29 ` Lai Jiangshan
2010-04-20 22:21 ` Paul E. McKenney
2010-04-21 8:17 ` Avi Kivity
2010-04-21 14:36 ` Paul E. McKenney
2010-04-20 21:55 ` [PATCH] kvm: use the correct RCU API Paul E. McKenney
2010-04-21 8:22 ` Avi Kivity
2010-04-21 8:22 ` Avi Kivity
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