Hi,
this series fixes hub_configure() error handling that causes hub->ports[i]
NULL pointer dereferences that were previously reported at:
"[PATCH] Prevent USB hub remove oops"
http://marc.info/?l=linux-kernel&m=136189072520909&w=4
https://bugzilla.redhat.com/show_bug.cgi?id=926907
This bug still exists in 3.11-rc6 and I've got an Oops during startup
caused by hub->ports[i] dereference in hub_quiesce().
The first patch implements what Alan Stern suggested in the
"[PATCH] Prevent USB hub remove oops" thread:
"All of these problems can be fixed in hub_configure by setting
hub->maxchild to the total number of allocated ports (or 0 if hub_ports
can't be allocated)."
http://marc.info/?l=linux-usb&m=136189486922963&w=4
The second patch uses slightly different approach because some
users ignore hub->maxchild and use hub->descriptor->bNbrPorts.
Krzysiek
Krzysztof Mazur (2):
usb: fix cleanup after failure in hub_configure()
usb: fail on usb_hub_create_port_device() errors
drivers/usb/core/hub.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
--
1.8.4.rc1.409.gbd48715
If the hub_configure() fails after setting the hdev->maxchild
the hub->ports might be NULL or point to uninitialized kzallocated
memory causing NULL pointer dereference in hub_quiesce() during cleanup.
Now after such error the hdev->maxchild is set to 0 to avoid cleanup
of uninitialized ports.
Suggested-by: Alan Stern <[email protected]>
Signed-off-by: Krzysztof Mazur <[email protected]>
---
drivers/usb/core/hub.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 558313d..588c3a3 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1339,7 +1339,7 @@ static int hub_configure(struct usb_hub *hub,
GFP_KERNEL);
if (!hub->ports) {
ret = -ENOMEM;
- goto fail;
+ goto fail_maxchild;
}
wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
@@ -1466,7 +1466,7 @@ static int hub_configure(struct usb_hub *hub,
ret = usb_get_status(hdev, USB_RECIP_DEVICE, 0, &hubstatus);
if (ret < 2) {
message = "can't get hub status";
- goto fail;
+ goto fail_maxchild;
}
le16_to_cpus(&hubstatus);
hcd = bus_to_hcd(hdev->bus);
@@ -1512,14 +1512,14 @@ static int hub_configure(struct usb_hub *hub,
&hub->tt, GFP_KERNEL);
if (ret < 0) {
message = "can't update HCD hub info";
- goto fail;
+ goto fail_maxchild;
}
}
ret = hub_hub_status(hub, &hubstatus, &hubchange);
if (ret < 0) {
message = "can't get hub status";
- goto fail;
+ goto fail_maxchild;
}
/* local power status reports aren't always correct */
@@ -1547,7 +1547,7 @@ static int hub_configure(struct usb_hub *hub,
hub->urb = usb_alloc_urb(0, GFP_KERNEL);
if (!hub->urb) {
ret = -ENOMEM;
- goto fail;
+ goto fail_maxchild;
}
usb_fill_int_urb(hub->urb, hdev, pipe, *hub->buffer, maxp, hub_irq,
@@ -1567,6 +1567,8 @@ static int hub_configure(struct usb_hub *hub,
hub_activate(hub, HUB_INIT);
return 0;
+fail_maxchild:
+ hdev->maxchild = 0;
fail:
dev_err (hub_dev, "config failed, %s (err %d)\n",
message, ret);
--
1.8.4.rc1.409.gbd48715
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 <[email protected]>
---
I'm not sure if failing in that case is a good idea, but other solutions
are more complex.
I tried also changing hdev->maxchild and skiping initialization
of later ports, but it didn't work because in some cases
hub->descriptor->bNbrPorts is used instead of hdev->maxchild.
With simulated usb_hub_create_port_device() failure I have an Oops
in hub_power_on().
Another possible solution is allowing for uninitialized ports and
checking for hub->ports[i] == NULL.
drivers/usb/core/hub.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 588c3a3..afd334b 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;
+ }
+ }
usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
--
1.8.4.rc1.409.gbd48715
On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
> If the hub_configure() fails after setting the hdev->maxchild
> the hub->ports might be NULL or point to uninitialized kzallocated
> memory causing NULL pointer dereference in hub_quiesce() during cleanup.
>
> Now after such error the hdev->maxchild is set to 0 to avoid cleanup
> of uninitialized ports.
The idea is good, but the implementation is a little silly...
> Suggested-by: Alan Stern <[email protected]>
> Signed-off-by: Krzysztof Mazur <[email protected]>
> ---
> drivers/usb/core/hub.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 558313d..588c3a3 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1339,7 +1339,7 @@ static int hub_configure(struct usb_hub *hub,
> GFP_KERNEL);
> if (!hub->ports) {
> ret = -ENOMEM;
> - goto fail;
> + goto fail_maxchild;
> }
>
> wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
> @@ -1567,6 +1567,8 @@ static int hub_configure(struct usb_hub *hub,
> hub_activate(hub, HUB_INIT);
> return 0;
>
> +fail_maxchild:
> + hdev->maxchild = 0;
> fail:
> dev_err (hub_dev, "config failed, %s (err %d)\n",
> message, ret);
Why bother with a separate jump label? Just set maxchild to 0 whenever
a failure occurs.
Alan Stern
On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
> 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 <[email protected]>
> ---
> I'm not sure if failing in that case is a good idea, but other solutions
> are more complex.
>
> I tried also changing hdev->maxchild and skiping initialization
> of later ports, but it didn't work because in some cases
> hub->descriptor->bNbrPorts is used instead of hdev->maxchild.
> With simulated usb_hub_create_port_device() failure I have an Oops
> in hub_power_on().
I think this patch is correct. However, we also should change the
other places that refer to bNbrPorts; make them use maxchild instead.
> Another possible solution is allowing for uninitialized ports and
> checking for hub->ports[i] == NULL.
No, if we can't allocate memory for all the ports then the whole thing
should fail.
Alan Stern
On Tue, Aug 20, 2013 at 02:14:42PM -0400, Alan Stern wrote:
> On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
>
> > If the hub_configure() fails after setting the hdev->maxchild
> > the hub->ports might be NULL or point to uninitialized kzallocated
> > memory causing NULL pointer dereference in hub_quiesce() during cleanup.
> >
> > Now after such error the hdev->maxchild is set to 0 to avoid cleanup
> > of uninitialized ports.
>
> The idea is good, but the implementation is a little silly...
>
> > Suggested-by: Alan Stern <[email protected]>
> > Signed-off-by: Krzysztof Mazur <[email protected]>
> > ---
> > drivers/usb/core/hub.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index 558313d..588c3a3 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -1339,7 +1339,7 @@ static int hub_configure(struct usb_hub *hub,
> > GFP_KERNEL);
> > if (!hub->ports) {
> > ret = -ENOMEM;
> > - goto fail;
> > + goto fail_maxchild;
> > }
> >
> > wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
>
> > @@ -1567,6 +1567,8 @@ static int hub_configure(struct usb_hub *hub,
> > hub_activate(hub, HUB_INIT);
> > return 0;
> >
> > +fail_maxchild:
> > + hdev->maxchild = 0;
> > fail:
> > dev_err (hub_dev, "config failed, %s (err %d)\n",
> > message, ret);
>
> 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.
Thanks,
Krzysiek
-- >8 --
Subject: [PATCH 1/2 v2] usb: fix cleanup after failure in hub_configure()
If the hub_configure() fails after setting the hdev->maxchild
the hub->ports might be NULL or point to uninitialized kzallocated
memory causing NULL pointer dereference in hub_quiesce() during cleanup.
Now after such error the hdev->maxchild is set to 0 to avoid cleanup
of uninitialized ports.
Signed-off-by: Krzysztof Mazur <[email protected]>
---
drivers/usb/core/hub.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 558313d..affed11 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1568,6 +1568,7 @@ static int hub_configure(struct usb_hub *hub,
return 0;
fail:
+ hdev->maxchild = 0;
dev_err (hub_dev, "config failed, %s (err %d)\n",
message, ret);
/* hub_disconnect() frees urb and descriptor */
--
1.8.4.rc1.409.gbd48715
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
On Tue, Aug 20, 2013 at 02:18:57PM -0400, Alan Stern wrote:
> On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
>
> > 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 <[email protected]>
> > ---
> > I'm not sure if failing in that case is a good idea, but other solutions
> > are more complex.
> >
> > I tried also changing hdev->maxchild and skiping initialization
> > of later ports, but it didn't work because in some cases
> > hub->descriptor->bNbrPorts is used instead of hdev->maxchild.
> > With simulated usb_hub_create_port_device() failure I have an Oops
> > in hub_power_on().
>
> I think this patch is correct. However, we also should change the
> other places that refer to bNbrPorts; make them use maxchild instead.
Ok, I can try to catch all such cases and fix problems with
maxchild < bNBrPorts, but I think that changing bNBrPorts to maxchild
might be not enough. For instance:
for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
if (hub->ports[port1 - 1]->power_is_on)
set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
else
usb_clear_port_feature(hub->hdev, port1,
USB_PORT_FEAT_POWER);
in hub_power_on() should be probably changed to something like:
for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
if (hub->ports[port1 - 1] && hub->ports[port1 - 1]->power_is_on)
set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
else
usb_clear_port_feature(hub->hdev, port1,
USB_PORT_FEAT_POWER);
to disable uninitialized ports.
>
> > Another possible solution is allowing for uninitialized ports and
> > checking for hub->ports[i] == NULL.
>
> No, if we can't allocate memory for all the ports then the whole thing
> should fail.
The usb_hub_create_port_device() might fail also in case of device_add()
error.
>
> Alan Stern
Thanks,
Krzysiek
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 <[email protected]>
---
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
On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
> On Tue, Aug 20, 2013 at 02:18:57PM -0400, Alan Stern wrote:
> > On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
> >
> > > 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 <[email protected]>
> > > ---
> > > I'm not sure if failing in that case is a good idea, but other solutions
> > > are more complex.
> > >
> > > I tried also changing hdev->maxchild and skiping initialization
> > > of later ports, but it didn't work because in some cases
> > > hub->descriptor->bNbrPorts is used instead of hdev->maxchild.
> > > With simulated usb_hub_create_port_device() failure I have an Oops
> > > in hub_power_on().
> >
> > I think this patch is correct. However, we also should change the
> > other places that refer to bNbrPorts; make them use maxchild instead.
>
> Ok, I can try to catch all such cases and fix problems with
> maxchild < bNBrPorts, but I think that changing bNBrPorts to maxchild
> might be not enough. For instance:
We should never have maxchild < bNbrPorts (unless maxchild is 0). But
just in case we do, changing the code is a good idea.
Besides, "hub->maxchild" is shorter and easier to read than
"hub->descriptor->bNbrPorts". :-)
> for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
> if (hub->ports[port1 - 1]->power_is_on)
> set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
> else
> usb_clear_port_feature(hub->hdev, port1,
> USB_PORT_FEAT_POWER);
>
> in hub_power_on() should be probably changed to something like:
>
> for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
> if (hub->ports[port1 - 1] && hub->ports[port1 - 1]->power_is_on)
> set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
> else
> usb_clear_port_feature(hub->hdev, port1,
> USB_PORT_FEAT_POWER);
>
> to disable uninitialized ports.
No. The ports above maxchild aren't merely uninitialized; they are
completely unused. We should ignore them altogether. Just replace
descriptor->bNbrPorts with maxchild.
> > > Another possible solution is allowing for uninitialized ports and
> > > checking for hub->ports[i] == NULL.
> >
> > No, if we can't allocate memory for all the ports then the whole thing
> > should fail.
>
> The usb_hub_create_port_device() might fail also in case of device_add()
> error.
The main reason for errors in device_add() is memory allocation
failure.
Regardless, if the port structures can't be initialized then let's
fail.
Alan Stern
On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
> > 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 <[email protected]>
> ---
> 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 */
Much better.
Alan Stern
On Tue, Aug 20, 2013 at 03:50:37PM -0400, Alan Stern wrote:
> On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
>
> > On Tue, Aug 20, 2013 at 02:18:57PM -0400, Alan Stern wrote:
> > > On Tue, 20 Aug 2013, Krzysztof Mazur wrote:
> > >
> > > > 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 <[email protected]>
> > > > ---
> > > > I'm not sure if failing in that case is a good idea, but other solutions
> > > > are more complex.
> > > >
> > > > I tried also changing hdev->maxchild and skiping initialization
> > > > of later ports, but it didn't work because in some cases
> > > > hub->descriptor->bNbrPorts is used instead of hdev->maxchild.
> > > > With simulated usb_hub_create_port_device() failure I have an Oops
> > > > in hub_power_on().
> > >
> > > I think this patch is correct. However, we also should change the
> > > other places that refer to bNbrPorts; make them use maxchild instead.
> >
> > Ok, I can try to catch all such cases and fix problems with
> > maxchild < bNBrPorts, but I think that changing bNBrPorts to maxchild
> > might be not enough. For instance:
>
> We should never have maxchild < bNbrPorts (unless maxchild is 0). But
> just in case we do, changing the code is a good idea.
>
> Besides, "hub->maxchild" is shorter and easier to read than
> "hub->descriptor->bNbrPorts". :-)
>
It's "hub->hdev->maxchild", but it's still shorter and
in many places it's just "hdev->maxchild" :)
I tested that with maxchild < bNbrPorts and there are no NULL pointer
dereferences anymore.
Krzysiek
-- >8 --
Subject: [PATCH 3/2] usb: don't use bNbrPorts after initialization
After successful initialization hub->descriptor->bNbrPorts and
hub->hdev->maxchild are equal, but using hub->hdev->maxchild is
preferred because that value is explicitly used for initialization
of hub->ports[].
Signed-off-by: Krzysztof Mazur <[email protected]>
---
drivers/usb/core/hub.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 292ffa8..86e353f 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -451,7 +451,7 @@ static void led_work (struct work_struct *work)
if (hdev->state != USB_STATE_CONFIGURED || hub->quiescing)
return;
- for (i = 0; i < hub->descriptor->bNbrPorts; i++) {
+ for (i = 0; i < hdev->maxchild; i++) {
unsigned selector, mode;
/* 30%-50% duty cycle */
@@ -500,7 +500,7 @@ static void led_work (struct work_struct *work)
}
if (!changed && blinkenlights) {
cursor++;
- cursor %= hub->descriptor->bNbrPorts;
+ cursor %= hdev->maxchild;
set_port_led(hub, cursor + 1, HUB_LED_GREEN);
hub->indicator[cursor] = INDICATOR_CYCLE;
changed++;
@@ -826,7 +826,7 @@ static unsigned hub_power_on(struct usb_hub *hub, bool do_delay)
else
dev_dbg(hub->intfdev, "trying to enable port power on "
"non-switchable hub\n");
- for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
+ for (port1 = 1; port1 <= hub->hdev->maxchild; port1++)
if (hub->ports[port1 - 1]->power_is_on)
set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
else
@@ -4655,9 +4655,7 @@ static void hub_events(void)
hub_dev = hub->intfdev;
intf = to_usb_interface(hub_dev);
dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
- hdev->state, hub->descriptor
- ? hub->descriptor->bNbrPorts
- : 0,
+ hdev->state, hdev->maxchild,
/* NOTE: expects max 15 ports... */
(u16) hub->change_bits[0],
(u16) hub->event_bits[0]);
@@ -4702,7 +4700,7 @@ static void hub_events(void)
}
/* deal with port status changes */
- for (i = 1; i <= hub->descriptor->bNbrPorts; i++) {
+ for (i = 1; i <= hdev->maxchild; i++) {
if (test_bit(i, hub->busy_bits))
continue;
connect_change = test_bit(i, hub->change_bits);
--
1.8.4.rc4.527.g303b16c
On Wed, 21 Aug 2013, Krzysztof Mazur wrote:
> > We should never have maxchild < bNbrPorts (unless maxchild is 0). But
> > just in case we do, changing the code is a good idea.
> >
> > Besides, "hub->maxchild" is shorter and easier to read than
> > "hub->descriptor->bNbrPorts". :-)
> >
>
> It's "hub->hdev->maxchild", but it's still shorter and
> in many places it's just "hdev->maxchild" :)
>
> I tested that with maxchild < bNbrPorts and there are no NULL pointer
> dereferences anymore.
>
> Krzysiek
> -- >8 --
> Subject: [PATCH 3/2] usb: don't use bNbrPorts after initialization
>
> After successful initialization hub->descriptor->bNbrPorts and
> hub->hdev->maxchild are equal, but using hub->hdev->maxchild is
> preferred because that value is explicitly used for initialization
> of hub->ports[].
>
> Signed-off-by: Krzysztof Mazur <[email protected]>
> ---
> drivers/usb/core/hub.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 292ffa8..86e353f 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -451,7 +451,7 @@ static void led_work (struct work_struct *work)
> if (hdev->state != USB_STATE_CONFIGURED || hub->quiescing)
> return;
>
> - for (i = 0; i < hub->descriptor->bNbrPorts; i++) {
> + for (i = 0; i < hdev->maxchild; i++) {
> unsigned selector, mode;
>
> /* 30%-50% duty cycle */
> @@ -500,7 +500,7 @@ static void led_work (struct work_struct *work)
> }
> if (!changed && blinkenlights) {
> cursor++;
> - cursor %= hub->descriptor->bNbrPorts;
> + cursor %= hdev->maxchild;
> set_port_led(hub, cursor + 1, HUB_LED_GREEN);
> hub->indicator[cursor] = INDICATOR_CYCLE;
> changed++;
> @@ -826,7 +826,7 @@ static unsigned hub_power_on(struct usb_hub *hub, bool do_delay)
> else
> dev_dbg(hub->intfdev, "trying to enable port power on "
> "non-switchable hub\n");
> - for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
> + for (port1 = 1; port1 <= hub->hdev->maxchild; port1++)
> if (hub->ports[port1 - 1]->power_is_on)
> set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
> else
> @@ -4655,9 +4655,7 @@ static void hub_events(void)
> hub_dev = hub->intfdev;
> intf = to_usb_interface(hub_dev);
> dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
> - hdev->state, hub->descriptor
> - ? hub->descriptor->bNbrPorts
> - : 0,
> + hdev->state, hdev->maxchild,
> /* NOTE: expects max 15 ports... */
> (u16) hub->change_bits[0],
> (u16) hub->event_bits[0]);
> @@ -4702,7 +4700,7 @@ static void hub_events(void)
> }
>
> /* deal with port status changes */
> - for (i = 1; i <= hub->descriptor->bNbrPorts; i++) {
> + for (i = 1; i <= hdev->maxchild; i++) {
> if (test_bit(i, hub->busy_bits))
> continue;
> connect_change = test_bit(i, hub->change_bits);
>
This is good. Combined with your other changes, it should fix all
the problems you described. You can add my Acked-by to these patches
now.
Alan Stern