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iser-target: Add iSCSI Extensions for RDMA (iSER) target driver

DISCUSSION Dan Carpenter 4 participants 5 messages Jan 4, 2016 – Jan 7, 2016 1 message not in the archive

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InfiniBand iSCSI extensions for RDMA (iSER) target
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Dan Carpenter

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#0 lore raw

Hello Nicholas Bellinger,

The patch b8d26b3be8b3: "iser-target: Add iSCSI Extensions for RDMA (iSER) target driver" from Mar 7, 2013, leads to the following static checker warning:

drivers/infiniband/ulp/isert/ib_isert.c:423 isert_device_get()
error: passing non negative 1 to ERR_PTR

drivers/infiniband/ulp/isert/ib_isert.c
417

   418          device->ib_device = cma_id->device;
   419          ret = isert_create_device_ib_res(device);
   420          if (ret) {
   421                  kfree(device);
   422                  mutex_unlock(&device_list_mutex);
   423                  return ERR_PTR(ret);

The warning here is because isert_create_device_ib_res() returns either a negative error code, zero or one. The documentation is not clear what that means. AHAHAHAHAHAHAHAH. I joke. There is no documentation.

Anyway, it's definitely a bug and it leads to a NULL dereference in the caller.

   424          }
   425  
   426          device->refcount++;
   427          list_add_tail(&device->dev_node, &device_list);
   428          isert_info("Created a new iser device %p refcount %d\n",
   429                     device, device->refcount);
   430          mutex_unlock(&device_list_mutex);
   431  
   432          return device;
   433  }

regards,
dan carpenter
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#1 lore raw

Hi Dan,

(Adding Sagi CC')

Quoted 25 lines · Dan Carpenter

Hello Nicholas Bellinger,

The patch b8d26b3be8b3: "iser-target: Add iSCSI Extensions for RDMA (iSER) target driver" from Mar 7, 2013, leads to the following static checker warning:

drivers/infiniband/ulp/isert/ib_isert.c:423 isert_device_get()
error: passing non negative 1 to ERR_PTR

drivers/infiniband/ulp/isert/ib_isert.c
417

   418          device->ib_device = cma_id->device;
   419          ret = isert_create_device_ib_res(device);
   420          if (ret) {
   421                  kfree(device);
   422                  mutex_unlock(&device_list_mutex);
   423                  return ERR_PTR(ret);

The warning here is because isert_create_device_ib_res() returns either a negative error code, zero or one. The documentation is not clear what that means. AHAHAHAHAHAHAHAH. I joke. There is no documentation.

Anyway, it's definitely a bug and it leads to a NULL dereference in the caller.

Quoted 11 lines
   424          }
   425  
   426          device->refcount++;
   427          list_add_tail(&device->dev_node, &device_list);
   428          isert_info("Created a new iser device %p refcount %d\n",
   429                     device, device->refcount);
   430          mutex_unlock(&device_list_mutex);
   431  
   432          return device;
   433  }

Looking at the current code, AFAICT isert_alloc_comps() -> ib_req_notify_cq() is the one case where this can happen, right..?

Here's a quick patch that I'm applying to target-pending/for-next, that always returns negative upon isert_create_device_ib_res() failure.

Thanks Dan!

drivers/infiniband/ulp/isert/ib_isert.c +5 -2
index 91eb22c..8954e12 100644
@@ -356,7 +356,7 @@ isert_create_device_ib_res(struct isert_device *device)
        dev_attr = &device->dev_attr;
        ret = isert_query_device(device->ib_device, dev_attr);
        if (ret)
-               return ret;
+               goto out;
 
        /* asign function handlers */
        if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS &&

@@ -372,7 +372,7 @@ isert_create_device_ib_res(struct isert_device *device)
 
        ret = isert_alloc_comps(device, dev_attr);
        if (ret)
-               return ret;
+               goto out;
 
        device->pd = ib_alloc_pd(device->ib_device);
        if (IS_ERR(device->pd)) {

@@ -390,6 +390,9 @@ isert_create_device_ib_res(struct isert_device *device)
 
 out_cq:
        isert_free_comps(device);
+out:
+       if (ret > 0)
+               ret = -EINVAL;
        return ret;
 }

A message that is not in the archive (sent off-list or not yet received): 1452104665.26125.22.camel-XoQW25Eq2zviZyQQd+hFbcojREIfoBdhmpATvIKMPHk@public.gmane.org

Acked-by
#3 lore raw
Quoted 24 lines
drivers/infiniband/ulp/isert/ib_isert.c +2 -2
index 91eb22c..8954e12 100644
@@ -356,7 +356,7 @@ isert_create_device_ib_res(struct isert_device *device)
         dev_attr = &device->dev_attr;
         ret = isert_query_device(device->ib_device, dev_attr);
         if (ret)
-               return ret;
+               goto out;
 
         /* asign function handlers */
         if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS &&

@@ -372,7 +372,7 @@ isert_create_device_ib_res(struct isert_device *device)
 
         ret = isert_alloc_comps(device, dev_attr);
         if (ret)
-               return ret;
+               goto out;
 
         device->pd = ib_alloc_pd(device->ib_device);
         if (IS_ERR(device->pd)) {

drivers/infiniband/ulp/isert/ib_isert.c isert_create_device_ib_res(struct isert_device *device)

Quoted 10 lines
drivers/infiniband/ulp/isert/ib_isert.c +3 -1
@@ -390,6 +390,9 @@ isert_create_device_ib_res(struct isert_device *device)
 
  out_cq:
         isert_free_comps(device);
+out:
+       if (ret > 0)
+               ret = -EINVAL;
         return ret;
  }
 
--

Looks fine,

Acked-by Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/[email protected]>

Thanks Nic, and thanks Dan for reporting!
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#5 lore raw

I see now that there is documentation in ib_req_notify_cq().

regards,
dan carpenter