[PATCH] jffs, clang: avoid some warnings of used uninitialized ptr

[Sebastian Huber]

On 05/10/2018 09:38, Daniel Hellstrom wrote:
>
> On 2018-10-05 09:34, Sebastian Huber wrote:
>> On 05/10/2018 09:25, Daniel Hellstrom wrote:
>>> On 2018-10-05 09:12, Sebastian Huber wrote:
>>>> On 05/10/2018 08:57, Daniel Hellstrom wrote:
>>>>> This fixes the following test failures on LEON3 UP/SMP when
>>>>> built using clang compiler:
>>>>>   * fsjffs2gc01
>>>>>   * jffs2_fserror
>>>>>   * jffs2_fspermission
>>>>>   * jffs2_fsrdwr
>>>>>   * jffs2_fstime
>>>>
>>>> The problem is probably in the 
>>>> rbtree_postorder_for_each_entry_safe(). Coverity Scan has also an 
>>>> issue with this macro. It is on my todo list. Please do not check 
>>>> in this patch.
>>> Ok I will not push it. Yes I was also thinking so. To use offsetof() 
>>> macro could be an option maybe, however the node type input is not 
>>> known to the rbtree_postorder_for_each_entry_safe() function even 
>>> though it only used from jffs2 code. 
>>
>> The Linux code uses typeof. We could do this also:
>>
>> diff --git a/cpukit/include/linux/rbtree.h 
>> b/cpukit/include/linux/rbtree.h
>> index 53c777e8c1..8fc575240f 100644
>> --- a/cpukit/include/linux/rbtree.h
>> +++ b/cpukit/include/linux/rbtree.h
>> @@ -126,12 +126,12 @@ static inline struct rb_node *rb_parent( struct 
>> rb_node *node )
>>    for ( \
>>      node = _RBTree_Postorder_first( \
>>        (RBTree_Control *) root, \
>> -      (size_t) ( (char *) &node->field - (char *) node ) \
>> +      offsetof( __typeof__( *node ), field ) \
>>      ); \
>>      node != NULL && ( \
>>        next = _RBTree_Postorder_next( \
>>          &node->field, \
>> -        (size_t) ( (char *) &node->field - (char *) node ) \
>> +        offsetof( __typeof__( *node ), field ) \
>>        ), \
>>        node != NULL \
>>      ); \
>>
>> It shouldn't be a big problem since at least GCC and clang supports 
>> it. It is also a standard C++ operator. It is already used in
>>
>> cpukit/libfs/src/jffs2/include/linux/list.h
>
> Ok, I will give it a try.
>

Thanks, please try this patch:

https://lists.rtems.org/pipermail/devel/2018-October/023181.html

-- 
Sebastian Huber, embedded brains GmbH

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