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* [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)
@ 2020-06-22 18:20 Dan Carpenter
  2020-06-23  2:22 ` Ran Wang
  0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2020-06-22 18:20 UTC (permalink / raw)
  To: kbuild, Nikhil Badola
  Cc: lkp, kbuild-all, linux-kernel, Felipe Balbi, Ran Wang, Peter Chen

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   625d3449788f85569096780592549d0340e9c0c7
commit: 75eaa498c99eebf9f9237656f69469e50197cc0b usb: gadget: Correct NULL pointer checking in fsl gadget
config: arm64-randconfig-m031-20200622 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)

# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=75eaa498c99eebf9f9237656f69469e50197cc0b
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git remote update linus
git checkout 75eaa498c99eebf9f9237656f69469e50197cc0b
vim +1055 drivers/usb/gadget/udc/fsl_udc_core.c

2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1047  static int fsl_ep_fifo_status(struct usb_ep *_ep)
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1048  {
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1049  	struct fsl_ep *ep;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1050  	struct fsl_udc *udc;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1051  	int size = 0;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1052  	u32 bitmask;
6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang            2011-11-23  1053  	struct ep_queue_head *qh;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1054  
75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola      2019-10-21 @1055  	if (!_ep || _ep->desc || !(_ep->desc->bEndpointAddress&0xF))
                                                                                                            ^^^^^^^^^
Reversed NULL test.  This will always return -ENODEV.  (Or possibly
crash.  But I suspect it always returns -ENODEV instead of crashing).

The container_of() macro doesn't dereference anything, btw.  It just
does pointer math.  I think it would be cleaner to use ep_index() like
the original code did.  In other words, perhaps it would look best
written like this:

	ep = container_of(_ep, struct fsl_ep, ep);
	if (!_ep || !_ep->desc || ep_index(ep) == 0)


2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1056  		return -ENODEV;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1057  
75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola      2019-10-21  1058  	ep = container_of(_ep, struct fsl_ep, ep);
75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola      2019-10-21  1059  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1060  	udc = (struct fsl_udc *)ep->udc;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1061  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1062  	if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN)
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1063  		return -ESHUTDOWN;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1064  
6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang            2011-11-23  1065  	qh = get_qh_by_ep(ep);
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1066  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1067  	bitmask = (ep_is_in(ep)) ? (1 << (ep_index(ep) + 16)) :
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1068  	    (1 << (ep_index(ep)));
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1069  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1070  	if (fsl_readl(&dr_regs->endptstatus) & bitmask)
6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang            2011-11-23  1071  		size = (qh->size_ioc_int_sts & DTD_PACKET_SIZE)
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1072  		    >> DTD_LENGTH_BIT_POS;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1073  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1074  	pr_debug("%s %u\n", __func__, size);
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1075  	return size;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1076  }

---
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https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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^ permalink raw reply	[flat|nested] 4+ messages in thread
* RE: [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)
  2020-06-22 18:20 [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055) Dan Carpenter
@ 2020-06-23  2:22 ` Ran Wang
  2020-06-23 10:36   ` Dan Carpenter
  0 siblings, 1 reply; 4+ messages in thread
From: Ran Wang @ 2020-06-23  2:22 UTC (permalink / raw)
  To: Dan Carpenter, kbuild
  Cc: lkp, kbuild-all, linux-kernel, Felipe Balbi, Peter Chen

Hi Dan

On Tuesday, June 23, 2020 2:20 AM, Dan Carpenter wrote:

<snip>

> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> New smatch warnings:
> drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we
> previously assumed '_ep->desc' could be null (see line 1055)
> 

<snip>

> 
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1047  static int fsl_ep_fifo_status(struct usb_ep *_ep)
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1048  {
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1049  	struct fsl_ep *ep;
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1050  	struct fsl_udc *udc;
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1051  	int size = 0;
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1052  	u32 bitmask;
> 6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang
> 2011-11-23  1053  	struct ep_queue_head *qh;
> 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> 2011-04-18  1054
> 75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola
> 2019-10-21 @1055  	if (!_ep || _ep->desc || !(_ep->desc->bEndpointAddress&0xF))
>                                          ^^^^^^^^^ Reversed NULL test.  This will always return -ENODEV.  (Or possibly crash.  But I suspect it always returns -ENODEV instead of crashing).

So the kernel test reports warning in case of '_ep->desc is null', right? 

My understanding is that this judgement would return -ENODEV when
executing '... || _ep-desc ||..' and never execute '_ep->desc->bEndpointAddress' part,
so crash would not happen, am I right?

> The container_of() macro doesn't dereference anything, btw.  It just does
> pointer math.  I think it would be cleaner to use ep_index() like the original
> code did.  In other words, perhaps it would look best written like this:

Yes, I agree using ep_index() would be easier for reading, just feel a little bit
uncomfortable to mix checking on _ep and it's container (ep) in the same line.

> 	ep = container_of(_ep, struct fsl_ep, ep);
> 	if (!_ep || !_ep->desc || ep_index(ep) == 0)
> 
> 

BTW, Nikhil Badola has left NXP (Freesale), so his email address is invalid now.

Thanks & Regards,
Ran

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)
  2020-06-23  2:22 ` Ran Wang
@ 2020-06-23 10:36   ` Dan Carpenter
  0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2020-06-23 10:36 UTC (permalink / raw)
  To: Ran Wang; +Cc: kbuild, lkp, kbuild-all, linux-kernel, Felipe Balbi, Peter Chen

On Tue, Jun 23, 2020 at 02:22:18AM +0000, Ran Wang wrote:
> Hi Dan
> 
> On Tuesday, June 23, 2020 2:20 AM, Dan Carpenter wrote:
> 
> <snip>
> 
> > 
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > New smatch warnings:
> > drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we
> > previously assumed '_ep->desc' could be null (see line 1055)
> > 
> 
> <snip>
> 
> > 
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1047  static int fsl_ep_fifo_status(struct usb_ep *_ep)
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1048  {
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1049  	struct fsl_ep *ep;
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1050  	struct fsl_udc *udc;
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1051  	int size = 0;
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1052  	u32 bitmask;
> > 6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang
> > 2011-11-23  1053  	struct ep_queue_head *qh;
> > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin
> > 2011-04-18  1054
> > 75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola
> > 2019-10-21 @1055  	if (!_ep || _ep->desc || !(_ep->desc->bEndpointAddress&0xF))
> >                                          ^^^^^^^^^ Reversed NULL test.  This will always return -ENODEV.  (Or possibly crash.  But I suspect it always returns -ENODEV instead of crashing).
> 
> So the kernel test reports warning in case of '_ep->desc is null', right? 
> 
> My understanding is that this judgement would return -ENODEV when
> executing '... || _ep-desc ||..' and never execute '_ep->desc->bEndpointAddress' part,
> so crash would not happen, am I right?

Yeah.  I can't imagine how _ep->desc is NULL.  It gets set to non-NULL
in fsl_ep_enable() and then set to NULL in fsl_ep_disable().

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 4+ messages in thread
* [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)
@ 2020-09-01  9:45 Dan Carpenter
  0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2020-09-01  9:45 UTC (permalink / raw)
  To: kbuild, Nikhil Badola
  Cc: lkp, kbuild-all, linux-kernel, Felipe Balbi, Ran Wang, Peter Chen

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master
head:   b51594df17d0ce80b9f9f35394a1f42d7ac94472
commit: 75eaa498c99eebf9f9237656f69469e50197cc0b usb: gadget: Correct NULL pointer checking in fsl gadget
config: powerpc64-randconfig-m031-20200901 (attached as .config)
compiler: powerpc-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)

Old smatch warnings:
drivers/usb/gadget/udc/fsl_udc_core.c:914 fsl_ep_queue() warn: variable dereferenced before check 'req' (see line 877)

# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=75eaa498c99eebf9f9237656f69469e50197cc0b 
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
git fetch --no-tags linus master
git checkout 75eaa498c99eebf9f9237656f69469e50197cc0b
vim +1055 drivers/usb/gadget/udc/fsl_udc_core.c

2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1047  static int fsl_ep_fifo_status(struct usb_ep *_ep)
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1048  {
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1049  	struct fsl_ep *ep;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1050  	struct fsl_udc *udc;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1051  	int size = 0;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1052  	u32 bitmask;
6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang            2011-11-23  1053  	struct ep_queue_head *qh;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1054  
75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola      2019-10-21 @1055  	if (!_ep || _ep->desc || !(_ep->desc->bEndpointAddress&0xF))
                                                                                                            ^^^^^^^^^
Reversed condition.  Missing !.

2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1056  		return -ENODEV;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1057  
75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola      2019-10-21  1058  	ep = container_of(_ep, struct fsl_ep, ep);
75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola      2019-10-21  1059  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1060  	udc = (struct fsl_udc *)ep->udc;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1061  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1062  	if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN)
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1063  		return -ESHUTDOWN;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1064  
6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang            2011-11-23  1065  	qh = get_qh_by_ep(ep);
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1066  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1067  	bitmask = (ep_is_in(ep)) ? (1 << (ep_index(ep) + 16)) :
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1068  	    (1 << (ep_index(ep)));
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1069  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1070  	if (fsl_readl(&dr_regs->endptstatus) & bitmask)
6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c     Li Yang            2011-11-23  1071  		size = (qh->size_ioc_int_sts & DTD_PACKET_SIZE)
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1072  		    >> DTD_LENGTH_BIT_POS;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1073  
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1074  	pr_debug("%s %u\n", __func__, size);
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1075  	return size;
2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c     Anatolij Gustschin 2011-04-18  1076  }

---
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-- links below jump to the message on this page --
2020-06-22 18:20 [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055) Dan Carpenter
2020-06-23  2:22 ` Ran Wang
2020-06-23 10:36   ` Dan Carpenter
2020-09-01  9:45 Dan Carpenter

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