| Message ID | 20200416083120.453718-1-toke@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [bpf,v2] cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled | expand |
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 70f71b154fa5..3fe0b006d2d2 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -469,7 +469,7 @@ static int cpu_map_update_elem(struct bpf_map *map, void *key, void *value, return -EOVERFLOW; /* Make sure CPU is a valid possible cpu */ - if (!cpu_possible(key_cpu)) + if (key_cpu >= nr_cpumask_bits || !cpu_possible(key_cpu)) return -ENODEV; if (qsize == 0) {
When the kernel is built with CONFIG_DEBUG_PER_CPU_MAPS, the cpumap code can trigger a spurious warning if CONFIG_CPUMASK_OFFSTACK is also set. This happens because in this configuration, NR_CPUS can be larger than nr_cpumask_bits, so the initial check in cpu_map_alloc() is not sufficient to guard against hitting the warning in cpumask_check(). Fix this by explicitly checking the supplied key against the nr_cpumask_bits variable before calling cpu_possible(). Fixes: 6710e1126934 ("bpf: introduce new bpf cpu map type BPF_MAP_TYPE_CPUMAP") Cc: Jesper Dangaard Brouer <brouer@redhat.com> Reported-by: Xiumei Mu <xmu@redhat.com> Tested-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> --- v2: - Move check to cpu_map_update_elem() to not affect max size of map kernel/bpf/cpumap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)