On Fri, Jun 08, 2018 at 03:33:28PM +0300, Dan Carpenter wrote:
> Hello Raed Salem,
>
> The patch ebb6796bd397: "IB/uverbs: Add read counters support" from
> May 31, 2018, leads to the following static checker warning:
>
> drivers/infiniband/core/uverbs_std_types_counters.c:105 ib_uverbs_handler_UVERBS_METHOD_COUNTERS_READ()
> error: 'uattr' dereferencing possible ERR_PTR()
>
> drivers/infiniband/core/uverbs_std_types_counters.c
> 83 static int UVERBS_HANDLER(UVERBS_METHOD_COUNTERS_READ)(struct ib_device *ib_dev,
> 84 struct ib_uverbs_file *file,
> 85 struct uverbs_attr_bundle *attrs)
> 86 {
> 87 struct ib_counters_read_attr read_attr = {};
> 88 const struct uverbs_attr *uattr;
> 89 struct ib_counters *counters =
> 90 uverbs_attr_get_obj(attrs, UVERBS_ATTR_READ_COUNTERS_HANDLE);
> 91 int ret;
> 92
> 93 if (!ib_dev->read_counters)
> 94 return -EOPNOTSUPP;
> 95
> 96 if (!atomic_read(&counters->usecnt))
> 97 return -EINVAL;
> 98
> 99 ret = uverbs_copy_from(&read_attr.flags, attrs,
> 100 UVERBS_ATTR_READ_COUNTERS_FLAGS);
> 101 if (ret)
> 102 return ret;
> 103
> 104 uattr = uverbs_attr_get(attrs, UVERBS_ATTR_READ_COUNTERS_BUFF);
> ^^^^^^^^^^^^^^^^^^^^^^^
> Does this require error handling?
It is the same as before, uverbs_attr_get cannot fail here.
We still need to do something sneaky to show to the compiler when it
can and cannot fail.. I have some work already toward this goal but got
distracted.
Jason
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