On Tue, Aug 20, 2013 at 02:59:18PM -0400, Alan Stern wrote:
> On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
>
> > > Why bother with a separate jump label? Just set maxchild to 0 whenever
> > > a failure occurs.
> > >
> >
> > Initially I had just straightforward "dev->maxchild = 0;" after fail,
> > but I changed that to simplify the second patch and be able to
> > use goto fail:
> >
> > ret = usb_hub_create_port_device(hub, i + 1);
> > if (ret < 0) {
> > dev_err(hub->intfdev,
> > "couldn't create port%d device.\n", i + 1);
> > hdev->maxchild = i;
> > goto fail;
> > }
> >
> > and avoid "return ret" here or something like
> >
> > if (hdev->maxchild == hub->descriptor->bNbrPorts)
> > hdev->maxchild = 0;
> >
> > in the fail path.
>
> The second patch can either clean up the port devices by hand, or else
> jump to a new label after the line that sets maxchild to 0.
> Alan Stern
I think that new label is better, it's equivalent to previous version
except for ugly rename of original fail label.
Thanks,
Krzysiek
-- >8 --
Subject: [PATCH 2/2 v2] usb: fail on usb_hub_create_port_device() errors
Ignoring usb_hub_create_port_device() errors cause later NULL pointer
deference when uninitialized hub->ports[i] entries are dereferenced
after port memory allocation error.
Signed-off-by: Krzysztof Mazur <krzys...@podlesie.net>
---
drivers/usb/core/hub.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index affed11..292ffa8 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1557,10 +1557,15 @@ static int hub_configure(struct usb_hub *hub,
if (hub->has_indicators && blinkenlights)
hub->indicator [0] = INDICATOR_CYCLE;
- for (i = 0; i < hdev->maxchild; i++)
- if (usb_hub_create_port_device(hub, i + 1) < 0)
+ for (i = 0; i < hdev->maxchild; i++) {
+ ret = usb_hub_create_port_device(hub, i + 1);
+ if (ret < 0) {
dev_err(hub->intfdev,
"couldn't create port%d device.\n", i + 1);
+ hdev->maxchild = i;
+ goto fail_keep_maxchild;
+ }
+ }
usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
@@ -1569,6 +1574,7 @@ static int hub_configure(struct usb_hub *hub,
fail:
hdev->maxchild = 0;
+fail_keep_maxchild:
dev_err (hub_dev, "config failed, %s (err %d)\n",
message, ret);
/* hub_disconnect() frees urb and descriptor */
--
1.8.4.rc1.409.gbd48715
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