Re: [PATCH] bcache: Zero initialize bucket in bch_allocator_thread

[Arnd Bergmann]

On Fri, Mar 8, 2019 at 3:11 AM Coly Li <colyli@xxxxxxx> wrote:
> On 2019/3/8 6:10 äå, Nathan Chancellor wrote:
> > When building with -Wsometimes-uninitialized, Clang warns:
> >
> > drivers/md/bcache/alloc.c:333:4: warning: variable 'bucket' is used
> > uninitialized whenever 'if' condition is false
> > [-Wsometimes-uninitialized]
> >
> > fifo_pop expands to a conditional depending on '!fifo_empty(...)', which
> > is the same condition as the while loop. It seems Clang can't piece
> > together that this condition will never been false as long as we are in
> > the while loop because they are the same condition. It's easy enough to
> > silence this warning by just explicitly zero initializing bucket.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/396
> > Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
>
> Hi Nathan,
>
> Nice catch, I will add it to my for-test. Thanks.

I saw the same warning but came up with a nicer (IMHO) fix, see
https://lore.kernel.org/lkml/20190322143507.1256436-1-arnd@xxxxxxxx/T/#u

        Arnd