This is a note to let you know that I've just added the patch titled cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled to the 5.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cpumap-avoid-warning-when-config_debug_per_cpu_maps-is-enabled.patch and it can be found in the queue-5.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bc23d0e3f717ced21fbfacab3ab887d55e5ba367 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@xxxxxxxxxx> Date: Thu, 16 Apr 2020 10:31:20 +0200 Subject: cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Tested-by: Xiumei Mu <xmu@xxxxxxxxxx> Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> Acked-by: Song Liu <songliubraving@xxxxxx> Link: https://lore.kernel.org/bpf/20200416083120.453718-1-toke@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/bpf/cpumap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -469,7 +469,7 @@ 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) { Patches currently in stable-queue which might be from toke@xxxxxxxxxx are queue-5.6/bpf-propagate-expected_attach_type-when-verifying-freplace-programs.patch queue-5.6/cpumap-avoid-warning-when-config_debug_per_cpu_maps-is-enabled.patch