| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 38/83] cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled | Date | Fri, 1 May 2020 15:23:17 +0200 |
| |
From: Toke Høiland-Jørgensen <toke@redhat.com>
commit bc23d0e3f717ced21fbfacab3ab887d55e5ba367 upstream.
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") Reported-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Xiumei Mu <xmu@redhat.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200416083120.453718-1-toke@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/bpf/cpumap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -486,7 +486,7 @@ static int cpu_map_update_elem(struct bp 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) {
|