Hi,

On 12/28/2015 07:25 AM, changbin...@intel.com wrote:
> From: "Du, Changbin" <changbin...@intel.com>
> 
> acm, ecm, hid, ncm, phonet, rndis and uvc functions all have double
> memory free issue. Set pointers to NULL after freed to avoid this.
> 
> Here explain how it happen on acm function, others has analogical case.
> 
> If acm_bind fails before allocate notification and acm->notify_req is
> not set to NULL after freed last time, double free will happen.
> 
> kernel BUG at mm/slub.c:3392!
> invalid opcode: 0000 [#1] PREEMPT SMP
> EIP is at kfree+0x172/0x180
> Call Trace:
> [<80c0e3b6>] ? usb_ep_autoconfig_ss+0x86/0x170
> [<80c13345>] gs_free_req+0x15/0x30
> [<80c12df1>] acm_bind+0x1c1/0x2d0
> [<80c0e9be>] usb_add_function+0x6e/0x120
> [<80c213cb>] acm_function_bind_config+0x2b/0x90
> 

Looks good to me again :)

Reviewed-by: Robert Baldyga <r.bald...@hackerion.com>

Thanks,
Robert Baldyga

> Signed-off-by: Du, Changbin <changbin...@intel.com>
> ---
> changes from v1: 
>   1. add same fix for ecm, hid, ncm... fucntions
>   2. patch title changed
> ---
>  drivers/usb/gadget/function/f_acm.c    |  8 ++++++--
>  drivers/usb/gadget/function/f_ecm.c    |  2 ++
>  drivers/usb/gadget/function/f_hid.c    |  5 ++++-
>  drivers/usb/gadget/function/f_ncm.c    |  2 ++
>  drivers/usb/gadget/function/f_phonet.c | 11 ++++++++---
>  drivers/usb/gadget/function/f_rndis.c  |  2 ++
>  drivers/usb/gadget/function/f_uvc.c    |  5 ++++-
>  7 files changed, 28 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_acm.c 
> b/drivers/usb/gadget/function/f_acm.c
> index 2fa1e80..e10c8d4 100644
> --- a/drivers/usb/gadget/function/f_acm.c
> +++ b/drivers/usb/gadget/function/f_acm.c
> @@ -699,8 +699,10 @@ acm_bind(struct usb_configuration *c, struct 
> usb_function *f)
>       return 0;
>  
>  fail:
> -     if (acm->notify_req)
> +     if (acm->notify_req) {
>               gs_free_req(acm->notify, acm->notify_req);
> +             acm->notify_req = NULL;
> +     }
>  
>       ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
>  
> @@ -713,8 +715,10 @@ static void acm_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>  
>       acm_string_defs[0].id = 0;
>       usb_free_all_descriptors(f);
> -     if (acm->notify_req)
> +     if (acm->notify_req) {
>               gs_free_req(acm->notify, acm->notify_req);
> +             acm->notify_req = NULL;
> +     }
>  }
>  
>  static void acm_free_func(struct usb_function *f)
> diff --git a/drivers/usb/gadget/function/f_ecm.c 
> b/drivers/usb/gadget/function/f_ecm.c
> index 7ad60ee..23092a2 100644
> --- a/drivers/usb/gadget/function/f_ecm.c
> +++ b/drivers/usb/gadget/function/f_ecm.c
> @@ -809,6 +809,7 @@ fail:
>       if (ecm->notify_req) {
>               kfree(ecm->notify_req->buf);
>               usb_ep_free_request(ecm->notify, ecm->notify_req);
> +             ecm->notify_req = NULL;
>       }
>  
>       ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
> @@ -907,6 +908,7 @@ static void ecm_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>  
>       kfree(ecm->notify_req->buf);
>       usb_ep_free_request(ecm->notify, ecm->notify_req);
> +     ecm->notify_req = NULL;
>  }
>  
>  static struct usb_function *ecm_alloc(struct usb_function_instance *fi)
> diff --git a/drivers/usb/gadget/function/f_hid.c 
> b/drivers/usb/gadget/function/f_hid.c
> index 99285b4..827e385 100644
> --- a/drivers/usb/gadget/function/f_hid.c
> +++ b/drivers/usb/gadget/function/f_hid.c
> @@ -679,8 +679,10 @@ fail:
>       ERROR(f->config->cdev, "hidg_bind FAILED\n");
>       if (hidg->req != NULL) {
>               kfree(hidg->req->buf);
> -             if (hidg->in_ep != NULL)
> +             if (hidg->in_ep != NULL) {
>                       usb_ep_free_request(hidg->in_ep, hidg->req);
> +                     hidg->req = NULL;
> +             }
>       }
>  
>       return status;
> @@ -912,6 +914,7 @@ static void hidg_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>       usb_ep_disable(hidg->in_ep);
>       kfree(hidg->req->buf);
>       usb_ep_free_request(hidg->in_ep, hidg->req);
> +     hidg->req = NULL;
>  
>       usb_free_all_descriptors(f);
>  }
> diff --git a/drivers/usb/gadget/function/f_ncm.c 
> b/drivers/usb/gadget/function/f_ncm.c
> index 7ad798a..510d1d7 100644
> --- a/drivers/usb/gadget/function/f_ncm.c
> +++ b/drivers/usb/gadget/function/f_ncm.c
> @@ -1459,6 +1459,7 @@ fail:
>       if (ncm->notify_req) {
>               kfree(ncm->notify_req->buf);
>               usb_ep_free_request(ncm->notify, ncm->notify_req);
> +             ncm->notify_req = NULL;
>       }
>  
>       ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
> @@ -1561,6 +1562,7 @@ static void ncm_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>  
>       kfree(ncm->notify_req->buf);
>       usb_ep_free_request(ncm->notify, ncm->notify_req);
> +     ncm->notify_req = NULL;
>  }
>  
>  static struct usb_function *ncm_alloc(struct usb_function_instance *fi)
> diff --git a/drivers/usb/gadget/function/f_phonet.c 
> b/drivers/usb/gadget/function/f_phonet.c
> index 157441d..5e146e1 100644
> --- a/drivers/usb/gadget/function/f_phonet.c
> +++ b/drivers/usb/gadget/function/f_phonet.c
> @@ -569,8 +569,10 @@ static int pn_bind(struct usb_configuration *c, struct 
> usb_function *f)
>       return 0;
>  
>  err_req:
> -     for (i = 0; i < phonet_rxq_size && fp->out_reqv[i]; i++)
> +     for (i = 0; i < phonet_rxq_size && fp->out_reqv[i]; i++) {
>               usb_ep_free_request(fp->out_ep, fp->out_reqv[i]);
> +             fp->out_reqv[i] = NULL;
> +     }
>       usb_free_all_descriptors(f);
>  err:
>       ERROR(cdev, "USB CDC Phonet: cannot autoconfigure\n");
> @@ -662,9 +664,12 @@ static void pn_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>       /* We are already disconnected */
>       if (fp->in_req)
>               usb_ep_free_request(fp->in_ep, fp->in_req);
> -     for (i = 0; i < phonet_rxq_size; i++)
> -             if (fp->out_reqv[i])
> +     for (i = 0; i < phonet_rxq_size; i++) {
> +             if (fp->out_reqv[i]) {
>                       usb_ep_free_request(fp->out_ep, fp->out_reqv[i]);
> +                     fp->out_reqv[i] = NULL;
> +             }
> +     }
>  
>       usb_free_all_descriptors(f);
>  }
> diff --git a/drivers/usb/gadget/function/f_rndis.c 
> b/drivers/usb/gadget/function/f_rndis.c
> index e587767..804a717 100644
> --- a/drivers/usb/gadget/function/f_rndis.c
> +++ b/drivers/usb/gadget/function/f_rndis.c
> @@ -821,6 +821,7 @@ fail:
>       if (rndis->notify_req) {
>               kfree(rndis->notify_req->buf);
>               usb_ep_free_request(rndis->notify, rndis->notify_req);
> +             rndis->notify_req = NULL;
>       }
>  
>       ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
> @@ -948,6 +949,7 @@ static void rndis_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>  
>       kfree(rndis->notify_req->buf);
>       usb_ep_free_request(rndis->notify, rndis->notify_req);
> +     rndis->notify_req = NULL;
>  }
>  
>  static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
> diff --git a/drivers/usb/gadget/function/f_uvc.c 
> b/drivers/usb/gadget/function/f_uvc.c
> index 29b41b5..f3a93bb 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -736,8 +736,10 @@ uvc_function_bind(struct usb_configuration *c, struct 
> usb_function *f)
>  error:
>       v4l2_device_unregister(&uvc->v4l2_dev);
>  
> -     if (uvc->control_req)
> +     if (uvc->control_req) {
>               usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
> +             uvc->control_req = NULL;
> +     }
>       kfree(uvc->control_buf);
>  
>       usb_free_all_descriptors(f);
> @@ -864,6 +866,7 @@ static void uvc_unbind(struct usb_configuration *c, 
> struct usb_function *f)
>       v4l2_device_unregister(&uvc->v4l2_dev);
>  
>       usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
> +     uvc->control_req = NULL;
>       kfree(uvc->control_buf);
>  
>       usb_free_all_descriptors(f);
> 


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