[dpdk-users] Segfault while freeing mbuf in the primary process

[Farbod <fshahinfar1@gmail.com>]

Hi,

I am using DPDK multi-processor mode for sending packets from one 
application (secondary) to another application (primary) using rings.
The primary applications role is to just free the packet with 
`rte_pktmbuf_free()`.

I encounter a SEGFAULT error in the line of `rte_pktmbuf_free()`.

My DPDK version is 19.11.1.

```

Signal: 11 (Segmentation fault), si_code: 1 (SEGV_MAPERR: address not 
mapped to object)
Backtrace (recent calls first) ---
(0): (+0x81a1ee) [0x562d35df51ee]
     bucket_enqueue_single at 
---/dpdk-19.11.1/drivers/mempool/bucket/rte_mempool_bucket.c:111 
(discriminator 3)
          108:   addr &= bd->bucket_page_mask;
          109:   hdr = (struct bucket_header *)addr;
110:
       -> 111:   if (likely(hdr->lcore_id == lcore_id)) {
          112:           if (hdr->fill_cnt < bd->obj_per_bucket - 1) {
          113: hdr->fill_cnt++;
          114:           } else {
      (inlined by) bucket_enqueue at 
---/dpdk-19.11.1/drivers/mempool/bucket/rte_mempool_bucket.c:148 
(discriminator 3)
          145:   int rc = 0;
146:
          147:   for (i = 0; i < n; i++) {
       -> 148:           rc = bucket_enqueue_single(bd, obj_table[i]);
          149:           RTE_ASSERT(rc == 0);
          150: }
[0x562d35cd2f8c]
     rte_mempool_ops_enqueue_bulk at 
---/dpdk-19.11.1/build/include/rte_mempool.h:786
       -> 786:   return ops->enqueue(mp, obj_table, n);
      (inlined by) __mempool_generic_put at 
---/dpdk-19.11.1/build/include/rte_mempool.h:1329
       -> 1329:          rte_mempool_ops_enqueue_bulk(mp, 
&cache->objs[cache->size],
      (inlined by) rte_mempool_generic_put at 
---/dpdk-19.11.1/build/include/rte_mempool.h:1365
       -> 1365:  __mempool_generic_put(mp, obj_table, n, cache);
      (inlined by) rte_mempool_put_bulk at 
---/dpdk-19.11.1/build/include/rte_mempool.h:1388
       -> 1388:  rte_mempool_generic_put(mp, obj_table, n, cache);
      (inlined by) rte_mempool_put at 
---/dpdk-19.11.1/build/include/rte_mempool.h:1406
       -> 1406:  rte_mempool_put_bulk(mp, &obj, 1);
      (inlined by) rte_mbuf_raw_free at 
---/dpdk-19.11.1/build/include/rte_mbuf.h:579
       -> 579:   rte_mempool_put(m->pool, m);
      (inlined by) rte_pktmbuf_free_seg at 
---/dpdk-19.11.1/build/include/rte_mbuf.h:1223
       -> 1223:          rte_mbuf_raw_free(m);         151:   if 
(local_stack->top > bd->bucket_stack_thresh) {
        (inlined by) rte_pktmbuf_free at ---/rte_mbuf.h:1244
       -> 1244: rte_pktmbuf_free_seg(m);
      (inlined by) ?? at --- /packet.h:199
       -> 199:     rte_pktmbuf_free(reinterpret_cast<struct rte_mbuf 
*>(pkt));

```

I have made sure that primary and secondary process does not share any 
cpu in common. The packets received in the primary application are valid 
and the information inside them is readable. It only runs in to SEGFAULT 
when I am trying to free the mubf structures.

I would like to mention that the applications are in two different 
projects and are built separately.

Thank you