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

On Thu, Aug 26, 2021 at 06:00:42PM +1000, Stephen Rothwell wrote:

Hi all,

After merging the kspp tree, today's linux-next build (arm
multi_v7_defconfig) produced these warnings:

In file included from ./arch/arm/include/generated/asm/rwonce.h:1,
                 from include/linux/compiler.h:264,
                 from include/uapi/linux/swab.h:6,
                 from include/linux/swab.h:5,
                 from arch/arm/include/asm/opcodes.h:86,
                 from arch/arm/include/asm/bug.h:7,
                 from include/linux/bug.h:5,
                 from include/linux/thread_info.h:13,
                 from include/asm-generic/current.h:5,
                 from ./arch/arm/include/generated/asm/current.h:1,
                 from include/linux/sched.h:12,
                 from include/linux/cgroup.h:12,
                 from kernel/cgroup/cgroup-internal.h:5,
                 from kernel/cgroup/cgroup.c:31:
kernel/cgroup/cgroup.c: In function 'of_css':
kernel/cgroup/cgroup.c:651:42: warning: array subscript '<unknown>' is outside the bounds of an interior zero-length array 'struct cgroup_subsys_state *[0]' [-Wzero-length-bounds]
  651 |   return rcu_dereference_raw(cgrp->subsys[cft->ss->id]);

Oh, that's cute. That's "with cgroups but no cgroup subsystems". :P I
will get this fixed.

[...]
Introduced by commit

  7d8aac16a0a8 ("Makefile: Enable -Wzero-length-bounds")

-- 
Cheers,
Stephen Rothwell

-- 
Kees Cook