2020-05-21 07:39:57

by Dinghao Liu

Subject: [PATCH] usb: musb: Fix runtime PM imbalance on error

When copy_from_user() returns an error code, a pairing
runtime PM usage counter decrement is needed to keep
the counter balanced.

Signed-off-by: Dinghao Liu <[email protected]>
---
drivers/usb/musb/musb_debugfs.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_debugfs.c b/drivers/usb/musb/musb_debugfs.c
index 7b6281ab62ed..837c38a5e4ef 100644
--- a/drivers/usb/musb/musb_debugfs.c
+++ b/drivers/usb/musb/musb_debugfs.c
@@ -178,8 +178,11 @@ static ssize_t musb_test_mode_write(struct file *file,

memset(buf, 0x00, sizeof(buf));

- if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+ if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) {
+ pm_runtime_mark_last_busy(musb->controller);
+ pm_runtime_put_autosuspend(musb->controller);
return -EFAULT;
+ }

if (strstarts(buf, "force host full-speed"))
test = MUSB_TEST_FORCE_HOST | MUSB_TEST_FORCE_FS;
--
2.17.1

2020-05-21 20:39:48

by Bin Liu

Subject: Re: [PATCH] usb: musb: Fix runtime PM imbalance on error

Hi,

On Thu, May 21, 2020 at 03:35:47PM +0800, Dinghao Liu wrote:
> When copy_from_user() returns an error code, a pairing
> runtime PM usage counter decrement is needed to keep
> the counter balanced.
>
> Signed-off-by: Dinghao Liu <[email protected]>
> ---
> drivers/usb/musb/musb_debugfs.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/musb/musb_debugfs.c b/drivers/usb/musb/musb_debugfs.c
> index 7b6281ab62ed..837c38a5e4ef 100644
> --- a/drivers/usb/musb/musb_debugfs.c
> +++ b/drivers/usb/musb/musb_debugfs.c
> @@ -178,8 +178,11 @@ static ssize_t musb_test_mode_write(struct file *file,
>
> memset(buf, 0x00, sizeof(buf));
>
> - if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> + if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) {
> + pm_runtime_mark_last_busy(musb->controller);
> + pm_runtime_put_autosuspend(musb->controller);
> return -EFAULT;
> + }

Thanks for catching the bug. Can you please instead move these lines to
the beginning of this function so that pm_runtime_get_sync() is not
called if copy_from_user() failed?

-Bin.

2020-05-22 01:24:52

by Dinghao Liu

Subject: Re: Re: [PATCH] usb: musb: Fix runtime PM imbalance on error

Sure.

Regards,
Dinghao

> Hi,
>
> On Thu, May 21, 2020 at 03:35:47PM +0800, Dinghao Liu wrote:
> > When copy_from_user() returns an error code, a pairing
> > runtime PM usage counter decrement is needed to keep
> > the counter balanced.
> >
> > Signed-off-by: Dinghao Liu <[email protected]>
> > ---
> > drivers/usb/musb/musb_debugfs.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/musb/musb_debugfs.c b/drivers/usb/musb/musb_debugfs.c
> > index 7b6281ab62ed..837c38a5e4ef 100644
> > --- a/drivers/usb/musb/musb_debugfs.c
> > +++ b/drivers/usb/musb/musb_debugfs.c
> > @@ -178,8 +178,11 @@ static ssize_t musb_test_mode_write(struct file *file,
> >
> > memset(buf, 0x00, sizeof(buf));
> >
> > - if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> > + if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) {
> > + pm_runtime_mark_last_busy(musb->controller);
> > + pm_runtime_put_autosuspend(musb->controller);
> > return -EFAULT;
> > + }
>
> Thanks for catching the bug. Can you please instead move these lines to
> the beginning of this function so that pm_runtime_get_sync() is not
> called if copy_from_user() failed?
>
> -Bin.