cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled

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: 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

parent 05ae98547a

commit 6cfb8c2ada

1 changed files with 1 additions and 1 deletions

									
										2

kernel/bpf/cpumap.c

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				@ -486,7 +486,7 @@ 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) {

cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled

2 kernel/bpf/cpumap.c Unescape Escape View File

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kernel/bpf/cpumap.c

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