Re: [PATCH] app: fix mbuf_autotest in case of defined RTE_LIBRTE_MBUF_DEBUG

[David Marchand <david.marchand@redhat.com>]

Hello,

On Mon, Mar 13, 2023 at 5:57 PM Pavel Ivashchenko
<pivashchenko@nfware.com> wrote:
>
> How to reproduce:
>
> 1. Define RTE_LIBRTE_MBUF_DEBUG
> 2. MALLOC_PERTURB_=178 DPDK_TEST=mbuf_autotest gdb --args obj-x86_64-linux-gnu/app/test/dpdk-test --file-prefix=mbuf_autotest
>
>    PANIC in rte_mbuf_sanity_check():
>    bad pkt_len
>
>    ...
>    #6  0x00007ffff7d3d4cc in rte_mbuf_sanity_check (m=m@entry=0x17f8c3400, is_header=is_header@entry=1) at ../lib/mbuf/rte_mbuf.c:384
>    #7  0x0000555555653d57 in rte_pktmbuf_free (m=0x17f8c3400) at ../lib/mbuf/rte_mbuf.h:1385
>    #8  0x000055555565c7a6 in test_nb_segs_and_next_reset () at ../app/test/test_mbuf.c:2752
>    #9  test_mbuf () at ../app/test/test_mbuf.c:2967
>    ...
>
>    (gdb) frame 6
>    #6  0x00007ffff7d3d4cc in rte_mbuf_sanity_check (m=m@entry=0x17f8c3400, is_header=is_header@entry=1) at ../lib/mbuf/rte_mbuf.c:384
>    384                  rte_panic("%s\n", reason);
>    (gdb) p/d m->pkt_len
>    $4 = 1500
>
> Fixes: efc6f9104c80 ("mbuf: fix reset on mbuf free")
> Cc: stable@dpdk.org
>
> Signed-off-by: Pavel Ivashchenko <pivashchenko@nfware.com>

LGTM, thanks.
Just a small comment.


> ---
>  app/test/test_mbuf.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
> index 6cbb03b0af..d471a23805 100644
> --- a/app/test/test_mbuf.c
> +++ b/app/test/test_mbuf.c
> @@ -2744,6 +2744,7 @@ test_nb_segs_and_next_reset(void)
>
>         /* split m0 chain in two, between m1 and m2 */
>         m0->nb_segs = 2;
> +       m0->pkt_len -= 500;

m0->pkt_len -= m2->data_len seems more readable and robust to me.

Opinions?


>         m1->next = NULL;
>         m2->nb_segs = 1;
>


-- 
David Marchand