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List:       linux-stable-commits
Subject:    Patch "cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled" has been added to the 5.6-st
From:       <gregkh () linuxfoundation ! org>
Date:       2020-04-30 15:09:46
Message-ID: 1588259386179204 () kroah ! com
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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@vger.kernel.org> know about it.


From bc23d0e3f717ced21fbfacab3ab887d55e5ba367 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Toke Høiland-Jørgensen?= <toke@redhat.com>
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@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
@@ -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@redhat.com 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
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