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