From: Tao Chen <chen.dylane@xxxxxxxxx> [ Upstream commit 1d244784be6b01162b732a5a7d637dfc024c3203 ] 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: Jinke Han <jinkehan@xxxxxxxxxxxxxx> Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20240910144111.1464912-2-chen.dylane@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@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 c76870bfd8167..2788da290c216 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -74,6 +74,9 @@ int array_map_alloc_check(union bpf_attr *attr) * access the elements. */ 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 f53b4f04b935c..d08fe64e0e453 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -464,6 +464,9 @@ 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; } -- 2.43.0
