From: Eric Blake <eblake@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: vsementsov@virtuozzo.com, berto@igalia.com,
qemu-devel@nongnu.org, qemu-block@nongnu.org, mreitz@redhat.com
Subject: Re: [PATCH v6 1/6] qcow2: Fix dangling pointer after reopen for 'file'
Date: Thu, 8 Jul 2021 08:26:15 -0500 [thread overview]
Message-ID: <20210708132615.g4hhii4qsxuxq2uz@redhat.com> (raw)
In-Reply-To: <20210708114709.206487-2-kwolf@redhat.com>
On Thu, Jul 08, 2021 at 01:47:04PM +0200, Kevin Wolf wrote:
> Without an external data file, s->data_file is a second pointer with the
> same value as bs->file. When changing bs->file to a different BdrvChild
> and freeing the old BdrvChild, s->data_file must also be updated,
> otherwise it points to freed memory and causes crashes.
>
> This problem was caught by iotests case 245.
>
> Fixes: df2b7086f169239ebad5d150efa29c9bb6d4f820
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
> block/qcow2.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
next prev parent reply other threads:[~2021-07-08 13:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-08 11:47 [PATCH v6 0/6] Make blockdev-reopen stable Kevin Wolf
2021-07-08 11:47 ` [PATCH v6 1/6] qcow2: Fix dangling pointer after reopen for 'file' Kevin Wolf
2021-07-08 13:26 ` Eric Blake [this message]
2021-07-08 13:52 ` Vladimir Sementsov-Ogievskiy
2021-07-08 11:47 ` [PATCH v6 2/6] block: Add bdrv_reopen_queue_free() Kevin Wolf
2021-07-08 11:47 ` [PATCH v6 3/6] block: Acquire AioContexts during bdrv_reopen_multiple() Kevin Wolf
2021-07-08 11:47 ` [PATCH v6 4/6] block: Support multiple reopening with x-blockdev-reopen Kevin Wolf
2021-07-08 11:47 ` [PATCH v6 5/6] iotests: Test reopening multiple devices at the same time Kevin Wolf
2021-07-08 11:47 ` [PATCH v6 6/6] block: Make blockdev-reopen stable API Kevin Wolf
2021-07-08 14:37 ` Eric Blake
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