Re: linux-next: build warning after merge of the btrfs-kdave tree

From: Stephen Rothwell
Date: Tue Dec 06 2016 - 17:38:25 EST


Hi David,

On Mon, 28 Nov 2016 11:02:30 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> After merging the btrfs-kdave tree, today's linux-next build (powerpc
> ppc64_defconfig) produced this warning:
>
> fs/btrfs/inode.c: In function 'run_delalloc_range':
> fs/btrfs/inode.c:1219:9: warning: 'cur_end' may be used uninitialized in this function [-Wmaybe-uninitialized]
> start = cur_end + 1;
> ^
> fs/btrfs/inode.c:1172:6: note: 'cur_end' was declared here
> u64 cur_end;
> ^
>
> Introduced by commit
>
> cow_file_range_async ("btrfs: Introduce COMPRESS reserve type to fix false enospc for compression")
>
> Presumably a false positive because ASSERT(0) panics?

Actually it does not if CONFIG_BTRFS_ASSERT is not set (which it isn't
for the above build), so this is not a false positive. I am still
seeing this.

--
Cheers,
Stephen Rothwell