From: Tao Chen chen.dylane@gmail.com
[ 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@didiglobal.com Signed-off-by: Tao Chen chen.dylane@gmail.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20240910144111.1464912-2-chen.dylane@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 c04e69f34e4d5..50b9bf57a4e3e 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 0c74cc9012d5c..dae9ed02a75be 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -455,6 +455,9 @@ 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; }