On Fri, Sep 22, 2023 at 10:53 AM Kees Cook <keesc...@chromium.org> wrote: > > Prepare for the coming implementation by GCC and Clang of the __counted_by > attribute. Flexible array members annotated with __counted_by can have > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions). > > As found with Coccinelle[1], add __counted_by for struct > mem_cgroup_threshold_ary. > > [1] > https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci > > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Shakeel Butt <shake...@google.com> > Cc: Roman Gushchin <roman.gushc...@linux.dev> > Cc: Johannes Weiner <han...@cmpxchg.org> > Cc: Michal Hocko <mho...@suse.com> > Cc: "Matthew Wilcox (Oracle)" <wi...@infradead.org> > Signed-off-by: Kees Cook <keesc...@chromium.org> > --- > include/linux/memcontrol.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 45d0c10e86cc..e0cfab58ab71 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -143,7 +143,7 @@ struct mem_cgroup_threshold_ary { > /* Size of entries[] */ > unsigned int size; > /* Array of thresholds */ > - struct mem_cgroup_threshold entries[]; > + struct mem_cgroup_threshold entries[] __counted_by(size);
Does 'size' here have to be a member of the same struct as entries? We have nodeinfo[] in struct mem_cgroup whose size is nr_node_ids which is global. Will __counted_by() work for that?
