Re: linux-next: build warnings after merge of the block tree

[Olof Johansson]

On Mon, Nov 25, 2013 at 7:35 PM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> Hi all,
>
> On Tue, 26 Nov 2013 13:29:46 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>>
>> After merging the block tree, today's linux-next build (arm
>> multi_v7_defconfig) produced these warnings:
>>
>> block/blk-merge.c: In function 'blk_rq_map_sg':
>> block/blk-merge.c:133:8: warning: 'bvprv.bv_len' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:171:23: note: 'bvprv.bv_len' was declared here
>> block/blk-merge.c:133:8: warning: 'bvprv.bv_page' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:171:23: note: 'bvprv.bv_page' was declared here
>> block/blk-merge.c:133:8: warning: 'bvprv.bv_offset' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:171:23: note: 'bvprv.bv_offset' was declared here
>> block/blk-merge.c: In function 'blk_bio_map_sg':
>> block/blk-merge.c:133:8: warning: 'bvprv.bv_len' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:233:23: note: 'bvprv.bv_len' was declared here
>> block/blk-merge.c:133:8: warning: 'bvprv.bv_offset' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:233:23: note: 'bvprv.bv_offset' was declared here
>> block/blk-merge.c:133:8: warning: 'bvprv.bv_page' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:233:23: note: 'bvprv.bv_page' was declared here
>> block/blk-merge.c: In function 'attempt_merge':
>> block/blk-merge.c:108:7: warning: 'end_bv.bv_offset' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:89:17: note: 'end_bv.bv_offset' was declared here
>> block/blk-merge.c:108:7: warning: 'end_bv.bv_page' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:89:17: note: 'end_bv.bv_page' was declared here
>> block/blk-merge.c:108:7: warning: 'end_bv.bv_len' may be used uninitialized in this function [-Wuninitialized]
>> block/blk-merge.c:89:17: note: 'end_bv.bv_len' was declared here
>>
>> arm has its own definition of BIOVEC_PHYS_MERGEABLE() if that is relevant.
>
> For an easier test case, the i386 defcongig does this as well.

I just noticed that i see this with gcc 4.7.0, but 4.8.1 does not warn.


-Olof
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