| Message ID | 311bc6d30b23427420133602c2833308310b7fcb.1610595364.git.Thinh.Nguyen@synopsys.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] usb: udc: core: Use lock when write to soft_connect | expand |
On Wed, Jan 13, 2021 at 07:38:28PM -0800, Thinh Nguyen wrote: ... > @@ -1543,10 +1546,12 @@ static ssize_t soft_connect_store(struct device *dev, > usb_gadget_udc_stop(udc); > } else { > dev_err(dev, "unsupported command '%s'\n", buf); > - return -EINVAL; > + ret = -EINVAL; > } > > - return n; > +out: > + mutex_unlock(&udc_lock); > + return ret; > } This is *very* tricky: the return value will be easily broken if someone adds any code later after the else body and before the "out" label.
Andy Shevchenko wrote: > > > On Thursday, January 14, 2021, Ahmed S. Darwish > <a.darwish@linutronix.de <mailto:a.darwish@linutronix.de>> wrote: > > On Wed, Jan 13, 2021 at 07:38:28PM -0800, Thinh Nguyen wrote: > ... > > @@ -1543,10 +1546,12 @@ static ssize_t soft_connect_store(struct > device *dev, > > usb_gadget_udc_stop(udc); > > } else { > > dev_err(dev, "unsupported command '%s'\n", buf); > > - return -EINVAL; > > + ret = -EINVAL; > > } > > > > - return n; > > > > Should be ret = n; here. > > > > +out: > > + mutex_unlock(&udc_lock); > > + return ret; > > } > > This is *very* tricky: the return value will be easily broken if > someone > adds any code later after the else body and before the "out" label. > > > > +1 and it’s not good pattern to assign return value at the definition > time (see comment above ). > > > -- > With Best Regards, > Andy Shevchenko > > Good point. I didn't think about that. Thanks guys. Thinh
Thinh Nguyen <Thinh.Nguyen@synopsys.com> writes: > Use lock to guard against concurrent access for soft-connect/disconnect > operations when writing to soft_connect sysfs. > > Cc: stable@vger.kernel.org > Fixes: 2ccea03a8f7e ("usb: gadget: introduce UDC Class") > Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com> Acked-by: Felipe Balbi <balbi@kernel.org>
On Thu, Jan 14, 2021 at 09:03:53AM +0200, Andy Shevchenko wrote: > On Thursday, January 14, 2021, Ahmed S. Darwish <a.darwish@linutronix.de> > wrote: > > > On Wed, Jan 13, 2021 at 07:38:28PM -0800, Thinh Nguyen wrote: > > ... > > > @@ -1543,10 +1546,12 @@ static ssize_t soft_connect_store(struct device > > *dev, > > > usb_gadget_udc_stop(udc); > > > } else { > > > dev_err(dev, "unsupported command '%s'\n", buf); > > > - return -EINVAL; > > > + ret = -EINVAL; > > > } > > > > > > - return n; > > > > Should be ret = n; here. Why? That happened higher up in the patch. thanks, greg k-h
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 6a62bbd01324..3363f5c282f1 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -1529,10 +1529,13 @@ static ssize_t soft_connect_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) { struct usb_udc *udc = container_of(dev, struct usb_udc, dev); + ssize_t ret = n; + mutex_lock(&udc_lock); if (!udc->driver) { dev_err(dev, "soft-connect without a gadget driver\n"); - return -EOPNOTSUPP; + ret = -EOPNOTSUPP; + goto out; } if (sysfs_streq(buf, "connect")) { @@ -1543,10 +1546,12 @@ static ssize_t soft_connect_store(struct device *dev, usb_gadget_udc_stop(udc); } else { dev_err(dev, "unsupported command '%s'\n", buf); - return -EINVAL; + ret = -EINVAL; } - return n; +out: + mutex_unlock(&udc_lock); + return ret; } static DEVICE_ATTR_WO(soft_connect);
Use lock to guard against concurrent access for soft-connect/disconnect operations when writing to soft_connect sysfs. Cc: stable@vger.kernel.org Fixes: 2ccea03a8f7e ("usb: gadget: introduce UDC Class") Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com> --- Changes in v2: - Consolidate mutex_unlock to a single place using "goto out" drivers/usb/gadget/udc/core.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) base-commit: 4e0dcf62ab4cf917d0cbe751b8bf229a065248d4