From: Paolo Bonzini <pbonzini@redhat.com>
To: 陈梁 <chenliang0016@icloud.com>
Cc: "kwolf@redhat.com" <kwolf@redhat.com>,
ChenLiang <chenliang88@huawei.com>,
"Huangweidong (C)" <weidong.huang@huawei.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Gonglei (Arei)" <arei.gonglei@huawei.com>,
"stefanha@redhat.com" <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] ide: fix double free
Date: Wed, 02 Jul 2014 15:09:37 +0200 [thread overview]
Message-ID: <53B40491.4000405@redhat.com> (raw)
In-Reply-To: <30F7BCE3-5A87-4AA0-86CA-E467842FE3A5@icloud.com>
Il 02/07/2014 14:54, 陈梁 ha scritto:
>> > The second call should have happened within dma_aio_cancel's call to
>> > bdrv_aio_cancel. This is the real bug.
> IMO, the second need not happened within dma_aio_cancel's call to bdrv_aio_cancel.
> The double free will be happened if dam_aio_cancel is called.
The callback must not be invoked after bdrv_aio_cancel. This is the
fundamental invariant of bdrv_aio_cancel. All implementations of AIOCB
must respect it, or bugs like this one happen.
Here, either bdrv_aio_cancel was not invoked, or the invariant was broken.
The other invariant, this time in dma-helpers.c, is that dma_bdrv_cb
either exits with no pending AIOCB, or it exits with a non-NULL
dbs->acb. If bdrv_aio_cancel was not invoked, this invariant was broken
because there is a pending AIOCB but it is not in dbs->acb.
Paolo
next prev parent reply other threads:[~2014-07-02 13:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-02 8:50 [Qemu-devel] [PATCH] ide: fix double free arei.gonglei
2014-07-02 9:04 ` Paolo Bonzini
2014-07-02 9:24 ` ChenLiang
2014-07-02 9:25 ` Paolo Bonzini
2014-07-02 9:46 ` Gonglei (Arei)
2014-07-02 10:16 ` Paolo Bonzini
2014-07-02 11:12 ` ChenLiang
2014-07-02 11:24 ` Paolo Bonzini
2014-07-02 11:33 ` ChenLiang
2014-07-02 11:40 ` Paolo Bonzini
2014-07-02 11:57 ` ChenLiang
2014-07-02 12:19 ` Paolo Bonzini
2014-07-02 12:46 ` 陈梁
2014-07-02 12:54 ` 陈梁
2014-07-02 13:09 ` Paolo Bonzini [this message]
2014-07-03 2:23 ` ChenLiang
2014-07-03 10:41 ` Paolo Bonzini
2014-07-07 8:12 ` ChenLiang
2014-07-07 12:38 ` Paolo Bonzini
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