On 11/23/22 5:52 AM, David Vernet wrote:
In commit fda01efc6160 ("bpf: Enable cgroups to be used as kptrs"), I added an 'int idx' variable to kfunc_init() which was meant to dynamically set the index of the btf id entries of the 'generic_dtor_ids' array. This was done to make the code slightly less brittle as the struct cgroup * kptr kfuncs such as bpf_cgroup_aquire() are compiled out if CONFIG_CGROUPS is not defined. This, however, causes an lkp build warning:kernel/bpf/helpers.c:2005:40: warning: multiple unsequencedmodifications to 'idx' [-Wunsequenced] .btf_id = generic_dtor_ids[idx++], Fix the warning by just hard-coding the indices. Fixes: fda01efc6160 ("bpf: Enable cgroups to be used as kptrs") Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: David Vernet <void@xxxxxxxxxxxxx>
I hit the same issue with clang build and used the same workaround below. Acked-by: Yonghong Song <yhs@xxxxxx>
--- kernel/bpf/helpers.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index e4e9db301db5..da2681ebb7c3 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2019,16 +2019,16 @@ static const struct btf_kfunc_id_set common_kfunc_set = {static int __init kfunc_init(void){ - int ret, idx = 0; + int ret; const struct btf_id_dtor_kfunc generic_dtors[] = { { - .btf_id = generic_dtor_ids[idx++], - .kfunc_btf_id = generic_dtor_ids[idx++] + .btf_id = generic_dtor_ids[0], + .kfunc_btf_id = generic_dtor_ids[1] }, #ifdef CONFIG_CGROUPS { - .btf_id = generic_dtor_ids[idx++], - .kfunc_btf_id = generic_dtor_ids[idx++] + .btf_id = generic_dtor_ids[2], + .kfunc_btf_id = generic_dtor_ids[3] }, #endif };
