* [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit
@ 2017-09-26 11:39 Jonathan Liu
2017-09-26 11:42 ` Jonathan Liu
2017-10-09 14:23 ` Bin Liu
0 siblings, 2 replies; 6+ messages in thread
From: Jonathan Liu @ 2017-09-26 11:39 UTC (permalink / raw)
To: linux-arm-kernel
This fixes a kernel oops when unloading the driver due to usb_put_phy
being called after usb_phy_generic_unregister when the device is
detached. Calling usb_phy_generic_unregister causes x->dev->driver to
be NULL in usb_put_phy and results in a NULL pointer dereference.
As we are now explicitly managing the lifetime of usb_phy,
devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
the probe error path.
Cc: stable at vger.kernel.org # v4.3+
Signed-off-by: Jonathan Liu <net147@gmail.com>
---
drivers/usb/musb/sunxi.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
index c9a09b5bb6e5..8eed61042103 100644
--- a/drivers/usb/musb/sunxi.c
+++ b/drivers/usb/musb/sunxi.c
@@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
sunxi_sram_release(musb->controller->parent);
+ usb_put_phy(glue->xceiv);
+
return 0;
}
@@ -781,7 +783,7 @@ static int sunxi_musb_probe(struct platform_device *pdev)
return PTR_ERR(glue->usb_phy);
}
- glue->xceiv = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
+ glue->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
if (IS_ERR(glue->xceiv)) {
ret = PTR_ERR(glue->xceiv);
dev_err(&pdev->dev, "Error getting usb-phy %d\n", ret);
@@ -803,11 +805,13 @@ static int sunxi_musb_probe(struct platform_device *pdev)
if (IS_ERR(glue->musb_pdev)) {
ret = PTR_ERR(glue->musb_pdev);
dev_err(&pdev->dev, "Error registering musb dev: %d\n", ret);
- goto err_unregister_usb_phy;
+ goto err_put_usb_phy;
}
return 0;
+err_put_usb_phy:
+ usb_put_phy(glue->xceiv);
err_unregister_usb_phy:
usb_phy_generic_unregister(glue->usb_phy);
return ret;
--
2.13.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit
2017-09-26 11:39 [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit Jonathan Liu
@ 2017-09-26 11:42 ` Jonathan Liu
2017-10-09 14:23 ` Bin Liu
1 sibling, 0 replies; 6+ messages in thread
From: Jonathan Liu @ 2017-09-26 11:42 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
On 26 September 2017 at 21:39, Jonathan Liu <net147@gmail.com> wrote:
> This fixes a kernel oops when unloading the driver due to usb_put_phy
> being called after usb_phy_generic_unregister when the device is
> detached. Calling usb_phy_generic_unregister causes x->dev->driver to
> be NULL in usb_put_phy and results in a NULL pointer dereference.
>
> As we are now explicitly managing the lifetime of usb_phy,
> devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
> the probe error path.
>
> Cc: stable at vger.kernel.org # v4.3+
> Signed-off-by: Jonathan Liu <net147@gmail.com>
> ---
> drivers/usb/musb/sunxi.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
> index c9a09b5bb6e5..8eed61042103 100644
> --- a/drivers/usb/musb/sunxi.c
> +++ b/drivers/usb/musb/sunxi.c
> @@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
> if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
> sunxi_sram_release(musb->controller->parent);
>
> + usb_put_phy(glue->xceiv);
> +
> return 0;
> }
>
> @@ -781,7 +783,7 @@ static int sunxi_musb_probe(struct platform_device *pdev)
> return PTR_ERR(glue->usb_phy);
> }
>
> - glue->xceiv = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
> + glue->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
> if (IS_ERR(glue->xceiv)) {
> ret = PTR_ERR(glue->xceiv);
> dev_err(&pdev->dev, "Error getting usb-phy %d\n", ret);
> @@ -803,11 +805,13 @@ static int sunxi_musb_probe(struct platform_device *pdev)
> if (IS_ERR(glue->musb_pdev)) {
> ret = PTR_ERR(glue->musb_pdev);
> dev_err(&pdev->dev, "Error registering musb dev: %d\n", ret);
> - goto err_unregister_usb_phy;
> + goto err_put_usb_phy;
> }
>
> return 0;
>
> +err_put_usb_phy:
> + usb_put_phy(glue->xceiv);
> err_unregister_usb_phy:
> usb_phy_generic_unregister(glue->usb_phy);
> return ret;
> --
> 2.13.2
>
Another way I could fix this would be to check if x->dev->driver is
NULL before dereferencing in usb_put_phy but I am not sure if this
breaks any expectations in the USB subsystem...
Regards,
Jonathan
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit
2017-09-26 11:39 [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit Jonathan Liu
2017-09-26 11:42 ` Jonathan Liu
@ 2017-10-09 14:23 ` Bin Liu
2017-10-09 21:17 ` Jonathan Liu
1 sibling, 1 reply; 6+ messages in thread
From: Bin Liu @ 2017-10-09 14:23 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
On Tue, Sep 26, 2017 at 09:39:23PM +1000, Jonathan Liu wrote:
> This fixes a kernel oops when unloading the driver due to usb_put_phy
> being called after usb_phy_generic_unregister when the device is
> detached. Calling usb_phy_generic_unregister causes x->dev->driver to
> be NULL in usb_put_phy and results in a NULL pointer dereference.
>
> As we are now explicitly managing the lifetime of usb_phy,
> devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
> the probe error path.
>
> Cc: stable at vger.kernel.org # v4.3+
> Signed-off-by: Jonathan Liu <net147@gmail.com>
> ---
> drivers/usb/musb/sunxi.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
> index c9a09b5bb6e5..8eed61042103 100644
> --- a/drivers/usb/musb/sunxi.c
> +++ b/drivers/usb/musb/sunxi.c
> @@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
> if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
> sunxi_sram_release(musb->controller->parent);
>
> + usb_put_phy(glue->xceiv);
Will devm_usb_put_phy() solve the issue too? Then you don't need the
changes in sunxi_musb_probe() below.
> +
> return 0;
> }
>
> @@ -781,7 +783,7 @@ static int sunxi_musb_probe(struct platform_device *pdev)
> return PTR_ERR(glue->usb_phy);
> }
>
> - glue->xceiv = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
> + glue->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
> if (IS_ERR(glue->xceiv)) {
> ret = PTR_ERR(glue->xceiv);
> dev_err(&pdev->dev, "Error getting usb-phy %d\n", ret);
> @@ -803,11 +805,13 @@ static int sunxi_musb_probe(struct platform_device *pdev)
> if (IS_ERR(glue->musb_pdev)) {
> ret = PTR_ERR(glue->musb_pdev);
> dev_err(&pdev->dev, "Error registering musb dev: %d\n", ret);
> - goto err_unregister_usb_phy;
> + goto err_put_usb_phy;
> }
>
> return 0;
>
> +err_put_usb_phy:
> + usb_put_phy(glue->xceiv);
> err_unregister_usb_phy:
> usb_phy_generic_unregister(glue->usb_phy);
> return ret;
> --
> 2.13.2
Regards,
-Bin.
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit
2017-10-09 14:23 ` Bin Liu
@ 2017-10-09 21:17 ` Jonathan Liu
2017-10-10 2:14 ` Bin Liu
0 siblings, 1 reply; 6+ messages in thread
From: Jonathan Liu @ 2017-10-09 21:17 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
On 10 October 2017 at 01:23, Bin Liu <b-liu@ti.com> wrote:
> Hi,
>
> On Tue, Sep 26, 2017 at 09:39:23PM +1000, Jonathan Liu wrote:
>> This fixes a kernel oops when unloading the driver due to usb_put_phy
>> being called after usb_phy_generic_unregister when the device is
>> detached. Calling usb_phy_generic_unregister causes x->dev->driver to
>> be NULL in usb_put_phy and results in a NULL pointer dereference.
>>
>> As we are now explicitly managing the lifetime of usb_phy,
>> devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
>> the probe error path.
>>
>> Cc: stable at vger.kernel.org # v4.3+
>> Signed-off-by: Jonathan Liu <net147@gmail.com>
>> ---
>> drivers/usb/musb/sunxi.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
>> index c9a09b5bb6e5..8eed61042103 100644
>> --- a/drivers/usb/musb/sunxi.c
>> +++ b/drivers/usb/musb/sunxi.c
>> @@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
>> if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
>> sunxi_sram_release(musb->controller->parent);
>>
>> + usb_put_phy(glue->xceiv);
>
> Will devm_usb_put_phy() solve the issue too? Then you don't need the
> changes in sunxi_musb_probe() below.
>
devm_usb_put_phy does solve the issue without changes in
sunxi_musb_probe but I think it is clearer that the lifetime is
explicitly managed if we don't mix implicit and explicit freeing of
resources.
>> +
>> return 0;
>> }
>>
>> @@ -781,7 +783,7 @@ static int sunxi_musb_probe(struct platform_device *pdev)
>> return PTR_ERR(glue->usb_phy);
>> }
>>
>> - glue->xceiv = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
>> + glue->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
>> if (IS_ERR(glue->xceiv)) {
>> ret = PTR_ERR(glue->xceiv);
>> dev_err(&pdev->dev, "Error getting usb-phy %d\n", ret);
>> @@ -803,11 +805,13 @@ static int sunxi_musb_probe(struct platform_device *pdev)
>> if (IS_ERR(glue->musb_pdev)) {
>> ret = PTR_ERR(glue->musb_pdev);
>> dev_err(&pdev->dev, "Error registering musb dev: %d\n", ret);
>> - goto err_unregister_usb_phy;
>> + goto err_put_usb_phy;
>> }
>>
>> return 0;
>>
>> +err_put_usb_phy:
>> + usb_put_phy(glue->xceiv);
>> err_unregister_usb_phy:
>> usb_phy_generic_unregister(glue->usb_phy);
>> return ret;
>> --
>> 2.13.2
>
> Regards,
> -Bin.
Regards,
Jonathan
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit
2017-10-09 21:17 ` Jonathan Liu
@ 2017-10-10 2:14 ` Bin Liu
2017-10-10 2:43 ` Jonathan Liu
0 siblings, 1 reply; 6+ messages in thread
From: Bin Liu @ 2017-10-10 2:14 UTC (permalink / raw)
To: linux-arm-kernel
On Tue, Oct 10, 2017 at 08:17:34AM +1100, Jonathan Liu wrote:
> Hi,
>
> On 10 October 2017 at 01:23, Bin Liu <b-liu@ti.com> wrote:
> > Hi,
> >
> > On Tue, Sep 26, 2017 at 09:39:23PM +1000, Jonathan Liu wrote:
> >> This fixes a kernel oops when unloading the driver due to usb_put_phy
> >> being called after usb_phy_generic_unregister when the device is
> >> detached. Calling usb_phy_generic_unregister causes x->dev->driver to
> >> be NULL in usb_put_phy and results in a NULL pointer dereference.
> >>
> >> As we are now explicitly managing the lifetime of usb_phy,
> >> devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
> >> the probe error path.
> >>
> >> Cc: stable at vger.kernel.org # v4.3+
> >> Signed-off-by: Jonathan Liu <net147@gmail.com>
> >> ---
> >> drivers/usb/musb/sunxi.c | 8 ++++++--
> >> 1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
> >> index c9a09b5bb6e5..8eed61042103 100644
> >> --- a/drivers/usb/musb/sunxi.c
> >> +++ b/drivers/usb/musb/sunxi.c
> >> @@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
> >> if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
> >> sunxi_sram_release(musb->controller->parent);
> >>
> >> + usb_put_phy(glue->xceiv);
> >
> > Will devm_usb_put_phy() solve the issue too? Then you don't need the
> > changes in sunxi_musb_probe() below.
> >
>
> devm_usb_put_phy does solve the issue without changes in
> sunxi_musb_probe but I think it is clearer that the lifetime is
> explicitly managed if we don't mix implicit and explicit freeing of
> resources.
Then what is the purpose of the devm_* API?
The original bug was that devm_usb_get_phy() is called in _probe, but
devm_usb_put_phy() was never called, which caused the device ref count
unbalanced. It is not related to implicit/explicit resource management.
devm_* is recommended whenever applicable.
Regards,
-Bin.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit
2017-10-10 2:14 ` Bin Liu
@ 2017-10-10 2:43 ` Jonathan Liu
0 siblings, 0 replies; 6+ messages in thread
From: Jonathan Liu @ 2017-10-10 2:43 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
On 10 October 2017 at 13:14, Bin Liu <b-liu@ti.com> wrote:
> On Tue, Oct 10, 2017 at 08:17:34AM +1100, Jonathan Liu wrote:
>> Hi,
>>
>> On 10 October 2017 at 01:23, Bin Liu <b-liu@ti.com> wrote:
>> > Hi,
>> >
>> > On Tue, Sep 26, 2017 at 09:39:23PM +1000, Jonathan Liu wrote:
>> >> This fixes a kernel oops when unloading the driver due to usb_put_phy
>> >> being called after usb_phy_generic_unregister when the device is
>> >> detached. Calling usb_phy_generic_unregister causes x->dev->driver to
>> >> be NULL in usb_put_phy and results in a NULL pointer dereference.
>> >>
>> >> As we are now explicitly managing the lifetime of usb_phy,
>> >> devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
>> >> the probe error path.
>> >>
>> >> Cc: stable at vger.kernel.org # v4.3+
>> >> Signed-off-by: Jonathan Liu <net147@gmail.com>
>> >> ---
>> >> drivers/usb/musb/sunxi.c | 8 ++++++--
>> >> 1 file changed, 6 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
>> >> index c9a09b5bb6e5..8eed61042103 100644
>> >> --- a/drivers/usb/musb/sunxi.c
>> >> +++ b/drivers/usb/musb/sunxi.c
>> >> @@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
>> >> if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
>> >> sunxi_sram_release(musb->controller->parent);
>> >>
>> >> + usb_put_phy(glue->xceiv);
>> >
>> > Will devm_usb_put_phy() solve the issue too? Then you don't need the
>> > changes in sunxi_musb_probe() below.
>> >
>>
>> devm_usb_put_phy does solve the issue without changes in
>> sunxi_musb_probe but I think it is clearer that the lifetime is
>> explicitly managed if we don't mix implicit and explicit freeing of
>> resources.
>
> Then what is the purpose of the devm_* API?
>
> The original bug was that devm_usb_get_phy() is called in _probe, but
> devm_usb_put_phy() was never called, which caused the device ref count
> unbalanced. It is not related to implicit/explicit resource management.
>
> devm_* is recommended whenever applicable.
>
Ok. Will use devm_usb_put_phy in v2 patch.
> Regards,
> -Bin.
>
Regards,
Jonathan
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-10-10 2:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2017-09-26 11:39 [PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit Jonathan Liu
2017-09-26 11:42 ` Jonathan Liu
2017-10-09 14:23 ` Bin Liu
2017-10-09 21:17 ` Jonathan Liu
2017-10-10 2:14 ` Bin Liu
2017-10-10 2:43 ` Jonathan Liu
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