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

From: David Sterba <[email-masked]>
Date: Fri, 3 May 2019 15:37:46 +0200

On Fri, May 03, 2019 at 10:21:05AM +1000, Stephen Rothwell wrote:
> Hi David,
> 
> After merging the btrfs-kdave tree, today's linux-next build (x86_64
> allmodconfig) produced this warning:
> 
> fs/btrfs/props.c: In function 'inherit_props':
> fs/btrfs/props.c:389:4: warning: 'num_bytes' may be used uninitialized in this function [-Wmaybe-uninitialized]
>     btrfs_block_rsv_release(fs_info, trans->block_rsv,
>     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>       num_bytes);
>       ~~~~~~~~~~
> 
> Probably introduced by commit
> 
>   b835a4a3faec ("btrfs: use the existing reserved items for our first prop for inheritance")
> 
> Looks like a false positive to me.

Agreed and gcc 8.3.1 does not report that. Kbuild bot reported that as
well and it uses 7.x.