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Date:   Wed, 26 Oct 2022 12:03:12 +0200
From:   Florian Lehner <dev@der-flo.net>
To:     bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next] bpf: check max_entries before allocating memory
Message-ID: <Y1kF4D4/19DOb/SS@der-flo.net>
References: <20221026085053.76561-1-dev@der-flo.net>
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On Wed, Oct 26, 2022 at 10:50:53AM +0200, Florian Lehner wrote:
> For maps of type BPF_MAP_TYPE_CPUMAP memory is allocated first before
> checking the max_entries argument. If then max_entries is greater than
> NR_CPUS additional work needs to be done to free allocated memory before
> an error is returned.
> This changes moves the check on max_entries before the allocation
> happens.
> 
> Signed-off-by: Florian Lehner <dev@der-flo.net>

I did have a look at the failing CI tests:

Running bpftool checks...
  Comparing /tmp/work/bpf/bpf/tools/include/uapi/linux/bpf.h (bpf_map_type)
  and /tmp/work/bpf/bpf/tools/bpf/bpftool/map.c (do_help() TYPE):
  {'cgroup_storage', 'cgroup_storage_deprecated'}
  Comparing /tmp/work/bpf/bpf/tools/include/uapi/linux/bpf.h (bpf_map_type)
  and /tmp/work/bpf/bpf/tools/bpf/bpftool/Documentation/bpftool-map.rst (TYPE):
  {'cgroup_storage', 'cgroup_storage_deprecated'}
  bpftool checks returned 1.

It looks to me these were introduced with commit
a48b4bf994296a380f9c79620ad4ee7bad4511e1 and are not related to this
proposed change.