Re: [libvirt] [PATCH 01/11] nodedev: Fix crash in libvirtd on vHBA creation path
On 01/02/2017 09:16 AM, Ján Tomko wrote:
On Fri, Nov 18, 2016 at 09:26:27AM -0500, John Ferlan wrote:
> Providing XML such as:
>
> <device>
> <name>vhba</name>
> <capability type='scsi_host'>
> <capability type='fc_host'>
> </capability>
> </capability>
> </device>
>
> would crash libvirt because the '<parent>' isn't a required field,
but
> for vHBA creation it's expected (day 1 issue - see commit id
'81d0ffbc').
> The nodedev.rng added in commit id '2c22a68c' has this as an optional
> field.
> NB: On normal udev discovery if a parent field wasn't found, it would be
> set to "computer" by udevSetParent, so this is a somewhat unique path.
>
> Signed-off-by: John Ferlan <jferlan(a)redhat.com>
> ---
> src/conf/node_device_conf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/conf/node_device_conf.c b/src/conf/node_device_conf.c
> index 1cd0baf..bf5b22f 100644
> --- a/src/conf/node_device_conf.c
> +++ b/src/conf/node_device_conf.c
> @@ -118,7 +118,7 @@ virNodeDeviceObjPtr
> virNodeDeviceFindByName(virNodeDeviceObjListPtr devs,
>
> for (i = 0; i < devs->count; i++) {
> virNodeDeviceObjLock(devs->objs[i]);
> - if (STREQ(devs->objs[i]->def->name, name))
> + if (STREQ_NULLABLE(devs->objs[i]->def->name, name))
Is this needed after patch 3/11?
Doesn't seem so - perhaps a bit of paranoia kicked in... Cannot remember
for sure since it's been so long...
I presume we do not store objects with NULL names in devs. In that
case
the callers should avoid calling this with NULL name - what is the point
of iterating over the array in that case?
Good assumption as objs[i]->def->name is the key for node devices (they
don't have uuids).
Good question - I have a faint recollection of tripping across this no
parent path based on some historical comment somewhere that said one
doesn't have to provide the parent in the nodedev-create XML... So I
went back, tried again with just this patch applied the create fails with:
error: Failed to create node device from vhba_nodedev.xml
error: internal error: Could not find parent device for 'new device'
Once patch 3 is applied the creation occurs "as advertised" (that is if
you don't supply a parent the code will find "a" parent that this vport
capable.
Whether this ever actually worked I don't recall and didn't chase.
In any case, I'll drop this patch (for now) and can post a followup that
would handle a NULL 'name' better (just return NULL immediately rather
than going through the whole loop needlessly).
John
Jan
> return devs->objs[i];
> virNodeDeviceObjUnlock(devs->objs[i]);
> }