Linux-USB Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH] [v2] usb: musb: Fix runtime PM imbalance on error
@ 2020-05-22  2:59 Dinghao Liu
  2020-05-22  5:12 ` Greg Kroah-Hartman
  0 siblings, 1 reply; 4+ messages in thread
From: Dinghao Liu @ 2020-05-22  2:59 UTC (permalink / raw)
  To: dinghao.liu, kjlu; +Cc: Bin Liu, Greg Kroah-Hartman, linux-usb, linux-kernel

When copy_from_user() returns an error code, there
is a runtime PM usage counter imbalance.

Fix this by moving copy_from_user() to the beginning
of this function.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
---
 drivers/usb/musb/musb_debugfs.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/musb/musb_debugfs.c b/drivers/usb/musb/musb_debugfs.c
index 7b6281ab62ed..30a89aa8a3e7 100644
--- a/drivers/usb/musb/musb_debugfs.c
+++ b/drivers/usb/musb/musb_debugfs.c
@@ -168,6 +168,11 @@ static ssize_t musb_test_mode_write(struct file *file,
 	u8			test;
 	char			buf[24];
 
+	memset(buf, 0x00, sizeof(buf));
+
+	if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
 	pm_runtime_get_sync(musb->controller);
 	test = musb_readb(musb->mregs, MUSB_TESTMODE);
 	if (test) {
@@ -176,11 +181,6 @@ static ssize_t musb_test_mode_write(struct file *file,
 		goto ret;
 	}
 
-	memset(buf, 0x00, sizeof(buf));
-
-	if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
-		return -EFAULT;
-
 	if (strstarts(buf, "force host full-speed"))
 		test = MUSB_TEST_FORCE_HOST | MUSB_TEST_FORCE_FS;
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] [v2] usb: musb: Fix runtime PM imbalance on error
  2020-05-22  2:59 [PATCH] [v2] usb: musb: Fix runtime PM imbalance on error Dinghao Liu
@ 2020-05-22  5:12 ` Greg Kroah-Hartman
  2020-05-22  5:22   ` dinghao.liu
  0 siblings, 1 reply; 4+ messages in thread
From: Greg Kroah-Hartman @ 2020-05-22  5:12 UTC (permalink / raw)
  To: Dinghao Liu; +Cc: kjlu, Bin Liu, linux-usb, linux-kernel

On Fri, May 22, 2020 at 10:59:02AM +0800, Dinghao Liu wrote:
> When copy_from_user() returns an error code, there
> is a runtime PM usage counter imbalance.
> 
> Fix this by moving copy_from_user() to the beginning
> of this function.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>  drivers/usb/musb/musb_debugfs.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)

What changed from v1?  Always show that below the --- line as the
documentation says to.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Re: [PATCH] [v2] usb: musb: Fix runtime PM imbalance on error
  2020-05-22  5:12 ` Greg Kroah-Hartman
@ 2020-05-22  5:22   ` dinghao.liu
  2020-05-22  5:32     ` Greg Kroah-Hartman
  0 siblings, 1 reply; 4+ messages in thread
From: dinghao.liu @ 2020-05-22  5:22 UTC (permalink / raw)
  To: Greg Kroah-Hartman; +Cc: kjlu, Bin Liu, linux-usb, linux-kernel

Sorry, it's my carelessness. In v1 I added pm_runtime_put_autosuspend()
after copy_from_user() to fix this problem. Since copy_from_user() is
moved to the beginning now, we need not to add PM decrement. 

Regards,
Dinghao

> On Fri, May 22, 2020 at 10:59:02AM +0800, Dinghao Liu wrote:
> > When copy_from_user() returns an error code, there
> > is a runtime PM usage counter imbalance.
> > 
> > Fix this by moving copy_from_user() to the beginning
> > of this function.
> > 
> > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> > ---
> >  drivers/usb/musb/musb_debugfs.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> What changed from v1?  Always show that below the --- line as the
> documentation says to.
> 
> thanks,
> 
> greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Re: [PATCH] [v2] usb: musb: Fix runtime PM imbalance on error
  2020-05-22  5:22   ` dinghao.liu
@ 2020-05-22  5:32     ` Greg Kroah-Hartman
  0 siblings, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2020-05-22  5:32 UTC (permalink / raw)
  To: dinghao.liu; +Cc: kjlu, Bin Liu, linux-usb, linux-kernel

On Fri, May 22, 2020 at 01:22:24PM +0800, dinghao.liu@zju.edu.cn wrote:
> Sorry, it's my carelessness. In v1 I added pm_runtime_put_autosuspend()
> after copy_from_user() to fix this problem. Since copy_from_user() is
> moved to the beginning now, we need not to add PM decrement. 

THat's fine, please put that information in a v3 and resend it.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, back to index

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-22  2:59 [PATCH] [v2] usb: musb: Fix runtime PM imbalance on error Dinghao Liu
2020-05-22  5:12 ` Greg Kroah-Hartman
2020-05-22  5:22   ` dinghao.liu
2020-05-22  5:32     ` Greg Kroah-Hartman

Linux-USB Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-usb/0 linux-usb/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-usb linux-usb/ https://lore.kernel.org/linux-usb \
		linux-usb@vger.kernel.org
	public-inbox-index linux-usb

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-usb


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git