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cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled

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commit bc23d0e3f7 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: 6710e11269 ("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>
This commit is contained in:
Toke Høiland-Jørgensen 2020-04-16 10:31:20 +02:00 • committed by Greg Kroah-Hartman
commit 1fc9f6c1b5
1 changed files with 1 additions and 1 deletions
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2
kernel/bpf/cpumap.c
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@ -455,7 +455,7 @@ 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) {