[libvirt] [PATCH] conf: fix crash when match a network iscsi hostdev with a host iscsi hostdev

[John Ferlan]

On 12/14/2014 10:09 PM, Luyao Huang wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1174053
> 
> When we use attach-device to coldplug a network iscsi hostdev,
> libvirt will check if there is already a device in XML. But if
> the 'b' is a host iscsi hostdev and 'a' is a network iscsi hostdev
> , libvirtd will crash in virDomainHostdevMatchSubsysSCSIiSCSI,
> because 'b' doesn't have a hostname.
> 
> Add a check in virDomainHostdevMatchSubsys, if the a's protocol
> and b's protocol is not the same.
> 
> backtrace like this:
> 
> 0  0x00007f850d6bc307 in virDomainHostdevMatchSubsysSCSIiSCSI at conf/domain_conf.c:10889
> 1  virDomainHostdevMatchSubsys at conf/domain_conf.c:10911
> 2  virDomainHostdevMatch at conf/domain_conf.c:10973
> 3  virDomainHostdevFind at conf/domain_conf.c:10998
> 4  0x00007f84f6a10560 in qemuDomainAttachDeviceConfig at qemu/qemu_driver.c:7223
> 5  qemuDomainAttachDeviceFlags at qemu/qemu_driver.c:7554
> 
> Signed-off-by: Luyao Huang <lhuang at redhat.com>
> ---
>  src/conf/domain_conf.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 5cf0b1a..eb63c93 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -11184,7 +11184,9 @@ static int
>  virDomainHostdevMatchSubsys(virDomainHostdevDefPtr a,
>                              virDomainHostdevDefPtr b)
>  {
> -    if (a->source.subsys.type != b->source.subsys.type)
> +    if (a->source.subsys.type != b->source.subsys.type ||
> +        (a->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI &&
> +         a->source.subsys.u.scsi.protocol != b->source.subsys.u.scsi.protocol))

While the check works - it's in the wrong place. It should be in the
subsequent switch.  I'll clean it up a bit and also reference the commit
id that introduced the issue as part of the commit message

John

>          return 0;
>  
>      switch (a->source.subsys.type) {
>