Re: [linux-next:master] [net_sched] 29f834aa32: kernel-selftests.net.so_txtime.sh.fail

[Eric Dumazet <edumazet@google.com>]

On Fri, Oct 20, 2023 at 9:18 AM kernel test robot <oliver.sang@intel.com> wrote:
>
>
>
> Hello,
>
> kernel test robot noticed "kernel-selftests.net.so_txtime.sh.fail" on:
>
> commit: 29f834aa326e659ed354c406056e94ea3d29706a ("net_sched: sch_fq: add 3 bands and WRR scheduling")
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>
> [test failed on linux-next/master e3b18f7200f45d66f7141136c25554ac1e82009b]
>
> in testcase: kernel-selftests
> version: kernel-selftests-x86_64-60acb023-1_20230329
> with following parameters:
>
>         group: net
>
>
>
> compiler: gcc-12
> test machine: 36 threads 1 sockets Intel(R) Core(TM) i9-10980XE CPU @ 3.00GHz (Cascade Lake) with 32G memory
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202310201422.a22b0999-oliver.sang@intel.com
>
>
> besides, we also noticed kernel-selftests.net.cmsg_time.sh.fail which does not
> happen on parent.
>
> 5579ee462dfe7682 29f834aa326e659ed354c406056
> ---------------- ---------------------------
>        fail:runs  %reproduction    fail:runs
>            |             |             |
>            :6          100%           6:6     kernel-selftests.net.cmsg_time.sh.fail
>            :6          100%           6:6     kernel-selftests.net.so_txtime.sh.fail
>
>
>
> # timeout set to 1500
> # selftests: net: so_txtime.sh
> #
> # SO_TXTIME ipv4 clock monotonic
> # payload:a delay:296 expected:0 (us)
> #
> # SO_TXTIME ipv6 clock monotonic
> # payload:a delay:279 expected:0 (us)
> #
> # SO_TXTIME ipv6 clock monotonic
> # ./so_txtime: recv: timeout: Resource temporarily unavailable
> not ok 30 selftests: net: so_txtime.sh # exit=1
>
> ....
>
> # timeout set to 1500
> # selftests: net: cmsg_time.sh
> #   Case UDPv4  - TXTIME abs returned '', expected 'OK'
> # FAIL - 1/36 cases failed
> not ok 59 selftests: net: cmsg_time.sh # exit=1
>
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20231020/202310201422.a22b0999-oliver.sang@intel.com
>
>
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>

Silly me....

I will send this fix:

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 8eacdb54e72f4412af1834bfdb2c387d41516349..f6fd0de293e583ad6ba505060ce12c74f349a1a2
100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -651,7 +651,7 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 begin:
        head = fq_pband_head_select(pband);
        if (!head) {
-               while (++retry < FQ_BANDS) {
+               while (++retry <= FQ_BANDS) {
                        if (++q->band_nr == FQ_BANDS)
                                q->band_nr = 0;
                        pband = &q->band_flows[q->band_nr];

Thanks !