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From: Markus Armbruster <armbru@redhat.com>
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Date: Tue, 28 Mar 2017 09:31:15 +0200
In-Reply-To: <20170327213407.GJ15423@localhost.localdomain> (Jeff Cody's
	message of "Mon, 27 Mar 2017 17:34:07 -0400")
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Subject: Re: [Qemu-devel] [PATCH RFC v3 for-2.9 02/11] rbd: Fix to cleanly
 reject -drive without pool or image
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To: Jeff Cody <jcody@redhat.com>
Cc: kwolf@redhat.com, jdurgin@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com

Jeff Cody <jcody@redhat.com> writes:

> On Mon, Mar 27, 2017 at 03:26:26PM +0200, Markus Armbruster wrote:
>> qemu_rbd_open() neglects to check pool and image are present.
>> Reproducer:
>> 
>>     $ qemu-system-x86_64 -nodefaults -drive if=none,driver=rbd,pool=p
>>     Segmentation fault (core dumped)
>
> This reproducer is wrong, I think.  Omitting the image should be caught
> earlier, but it is an error caught by the rbd_open() call.

Turns out the crash I observed was an artifact of my testing
instrumentation.

> What doesn't work is omitting the pool name, and that causes an abort()
> from rados_ioctx_create(), e.g.:
>
>
> $ qemu-system-x86_64 -nodefaults -drive driver=rbd,id=rbd,image=i,server.0.port=6789,server.0.host=192.168.15.180
> terminate called after throwing an instance of 'std::logic_error'
>   what():  basic_string::_M_construct null not valid
> Aborted (core dumped)
>
>
>>     $ qemu-system-x86_64 -nodefaults -drive if=none,driver=rbd,image=i
>>     qemu-system-x86_64: -drive if=none,driver=rbd,image=i: error opening pool (null)
>> 
>> Doesn't affect -drive with file=..., because qemu_rbd_parse_filename()
>> always sets both pool and image.
>> 
>> Doesn't affect -blockdev, because pool and image are mandatory in the
>> QAPI schema.
>> 
>> Fix by adding the missing checks.
>> 
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> With an updated commit message:
>
> Reviewed-by: Jeff Cody <jcody@redhat.com>

Thanks!