On Mon, Sep 9, 2024 at 12:14 AM Tao Chen <chen.dylane@xxxxxxxxx> wrote: > > Percpu map is often used, but the map value size limit often ignored, > like issue: https://github.com/iovisor/bcc/issues/2519. Actually, > percpu map value size is bound by PCPU_MIN_UNIT_SIZE, so we > can check the value size whether it exceeds PCPU_MIN_UNIT_SIZE first, > like percpu map of local_storage. Maybe the error message seems clearer > compared with "cannot allocate memory". > > Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx> > Signed-off-by: jinke han <jinkehan@xxxxxxxxxxxxxx> names in SOB should be capitalized the check is useful, so: Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > --- > kernel/bpf/arraymap.c | 3 +++ > kernel/bpf/hashtab.c | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c > index a43e62e2a8bb..79660e3fca4c 100644 > --- a/kernel/bpf/arraymap.c > +++ b/kernel/bpf/arraymap.c > @@ -73,6 +73,9 @@ int array_map_alloc_check(union bpf_attr *attr) > /* avoid overflow on round_up(map->value_size) */ > if (attr->value_size > INT_MAX) > return -E2BIG; > + /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */ > + if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE) > + return -E2BIG; > > return 0; > } > diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c > index 45c7195b65ba..b14b87463ee0 100644 > --- a/kernel/bpf/hashtab.c > +++ b/kernel/bpf/hashtab.c > @@ -462,6 +462,9 @@ static int htab_map_alloc_check(union bpf_attr *attr) > * kmalloc-able later in htab_map_update_elem() > */ > return -E2BIG; > + /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */ > + if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE) > + return -E2BIG; > > return 0; > } > -- > 2.25.1 >
