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Dan Carpenter

2020-Jun-02 09:42 UTC

[PATCH] vdpa: bypass waking up vhost_woker for vdpa vq kick

Hi Zhu,

url:   
https://github.com/0day-ci/linux/commits/Zhu-Lingshan/vdpa-bypass-waking-up-vhost_woker-for-vdpa-vq-kick/20200526-133819
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: x86_64-randconfig-m001-20200529 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-13) 9.3.0

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

smatch warnings:
drivers/vhost/vdpa.c:348 vhost_vdpa_set_vring_kick() error: uninitialized symbol
'r'.

#
https://github.com/0day-ci/linux/commit/a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d
vim +/r +348 drivers/vhost/vdpa.c

a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  316  static long
vhost_vdpa_set_vring_kick(struct vhost_virtqueue *vq,
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  317  				      void __user *argp)
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  318  {
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  319  	bool pollstart = false, pollstop =
false;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  320  	struct file *eventfp, *filep =
NULL;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  321  	struct vhost_vring_file f;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  322  	long r;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  323  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  324  	if (copy_from_user(&f, argp,
sizeof(f)))
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  325  		return -EFAULT;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  326  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  327  	eventfp = f.fd == -1 ? NULL :
eventfd_fget(f.fd);
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  328  	if (IS_ERR(eventfp)) {
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  329  		r = PTR_ERR(eventfp);
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  330  		return r;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  331  	}
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  332  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  333  	if (eventfp != vq->kick) {
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  334  		pollstop = (filep = vq->kick)
!= NULL;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  335  		pollstart = (vq->kick =
eventfp) != NULL;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  336  	} else
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  337  		filep = eventfp;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  338  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  339  	if (pollstop &&
vq->handle_kick)
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  340  		vhost_vdpa_poll_stop(vq);
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  341  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  342  	if (filep)
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  343  		fput(filep);
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  344  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  345  	if (pollstart &&
vq->handle_kick)
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  346  		r = vhost_vdpa_poll_start(vq);

"r" not initialized on else path.

a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  347  
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26 @348  	return r;
a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  349  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org
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Jason Wang

2020-Jun-02 10:16 UTC

head link

[PATCH] vdpa: bypass waking up vhost_woker for vdpa vq kick

On 2020/6/2 ??5:42, Dan Carpenter wrote:> Hi Zhu,
>
> url:   
https://github.com/0day-ci/linux/commits/Zhu-Lingshan/vdpa-bypass-waking-up-vhost_woker-for-vdpa-vq-kick/20200526-133819
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git
linux-next
> config: x86_64-randconfig-m001-20200529 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-13) 9.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kbuild test robot <lkp at intel.com>
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
>
> smatch warnings:
> drivers/vhost/vdpa.c:348 vhost_vdpa_set_vring_kick() error: uninitialized
symbol 'r'.
>
> #
https://github.com/0day-ci/linux/commit/a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d
> git remote add linux-review https://github.com/0day-ci/linux
> git remote update linux-review
> git checkout a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d
> vim +/r +348 drivers/vhost/vdpa.c
>
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  316  static long
vhost_vdpa_set_vring_kick(struct vhost_virtqueue *vq,
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  317  				      void __user *argp)
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  318  {
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  319  	bool pollstart = false,
pollstop = false;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  320  	struct file *eventfp, *filep
= NULL;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  321  	struct vhost_vring_file f;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  322  	long r;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  323
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  324  	if (copy_from_user(&f,
argp, sizeof(f)))
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  325  		return -EFAULT;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  326
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  327  	eventfp = f.fd == -1 ? NULL :
eventfd_fget(f.fd);
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  328  	if (IS_ERR(eventfp)) {
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  329  		r = PTR_ERR(eventfp);
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  330  		return r;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  331  	}
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  332
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  333  	if (eventfp != vq->kick) {
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  334  		pollstop = (filep =
vq->kick) != NULL;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  335  		pollstart = (vq->kick =
eventfp) != NULL;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  336  	} else
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  337  		filep = eventfp;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  338
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  339  	if (pollstop &&
vq->handle_kick)
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  340  		vhost_vdpa_poll_stop(vq);
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  341
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  342  	if (filep)
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  343  		fput(filep);
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  344
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  345  	if (pollstart &&
vq->handle_kick)
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  346  		r =
vhost_vdpa_poll_start(vq);
>
> "r" not initialized on else path.
>
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  347
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26 @348  	return r;
> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  349  }

Will fix.

Thanks

> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org

Jason Wang

2020-Jun-02 11:10 UTC

head link

[PATCH] vdpa: bypass waking up vhost_woker for vdpa vq kick

On 2020/6/2 ??6:16, Jason Wang wrote:>
> On 2020/6/2 ??5:42, Dan Carpenter wrote:
>> Hi Zhu,
>>
>> url: 
>>
https://github.com/0day-ci/linux/commits/Zhu-Lingshan/vdpa-bypass-waking-up-vhost_woker-for-vdpa-vq-kick/20200526-133819
>>
>> base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git 
>> linux-next
>> config: x86_64-randconfig-m001-20200529 (attached as .config)
>> compiler: gcc-9 (Debian 9.3.0-13) 9.3.0
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kbuild test robot <lkp at intel.com>
>> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
>>
>> smatch warnings:
>> drivers/vhost/vdpa.c:348 vhost_vdpa_set_vring_kick() error: 
>> uninitialized symbol 'r'.
>>
>> # 
>>
https://github.com/0day-ci/linux/commit/a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d
>>
>> git remote add linux-review https://github.com/0day-ci/linux
>> git remote update linux-review
>> git checkout a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d
>> vim +/r +348 drivers/vhost/vdpa.c
>>
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 316? static long 
>> vhost_vdpa_set_vring_kick(struct vhost_virtqueue *vq,
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26 317??????????????????????? 
>> void __user *argp)
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 318? {
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 319????? bool pollstart = 
>> false, pollstop = false;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 320????? struct file 
>> *eventfp, *filep = NULL;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 321????? struct 
>> vhost_vring_file f;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 322????? long r;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 323
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 324????? if 
>> (copy_from_user(&f, argp, sizeof(f)))
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 325????????? return -EFAULT;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 326
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 327????? eventfp = f.fd == -1 
>> ? NULL : eventfd_fget(f.fd);
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 328????? if (IS_ERR(eventfp)) {
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 329????????? r = 
>> PTR_ERR(eventfp);
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 330????????? return r;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 331????? }
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 332
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 333????? if (eventfp != 
>> vq->kick) {
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 334????????? pollstop = 
>> (filep = vq->kick) != NULL;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 335????????? pollstart = 
>> (vq->kick = eventfp) != NULL;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 336????? } else
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 337????????? filep = eventfp;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 338
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 339????? if (pollstop
&&
>> vq->handle_kick)
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 340 vhost_vdpa_poll_stop(vq);
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 341
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 342????? if (filep)
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 343 fput(filep);
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 344
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 345????? if (pollstart
&&
>> vq->handle_kick)
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 346????????? r = 
>> vhost_vdpa_poll_start(vq);
>>
>> "r" not initialized on else path.
>>
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 347
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26 @348????? return r;
>> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26? 349? }
>
>
> Will fix.
>
> Thanks 

Lingshan reminds me that we've posted V2 which reuses the vhost.c 
implementation for polling.

So there's no need for the fix.

Thanks

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