Re: [dpdk-dev] Getting crash in rte_pktmbuf_alloc with 16.11 DPDK

[Olivier Matz <olivier.matz@6wind.com>]

Hi,

On Fri, 17 Mar 2017 13:09:17 +0800, Yuanhan Liu <yuanhan.liu@linux.intel.com> wrote:
> On Fri, Mar 17, 2017 at 03:46:53AM +0000, Dey, Souvik wrote:
> > Hi ,
> >               I am trying to do rte_pktmbuf_alloc from a mempool within a secondary process after doing a rte_mempool_lookup for the same mempool. But the rte_pktmbuf_alloc crashes with the below backtrace  
> 
> I believe it's yet another "accessing a local process pointer in a shared
> memory" issue in the multiple process model. Here is a similar issue I have
> just fixed for virtio pmd in last release.
> 
>     commit 6d890f8ab51295045a53f41c4d2654bb1f01cf38
>     Author: Yuanhan Liu <yuanhan.liu@linux.intel.com>
>     Date:   Fri Jan 6 18:16:19 2017 +0800
>     
>         net/virtio: fix multiple process support
>     

Another idea is that your 2 processes (primary and secondary) do not
have the same configuration or build system. This was discussed a bit
here:

http://dpdk.org/dev/patchwork/patch/16868/

Can you provide a minimal example application that reproduces the
issue?

Regards,
Olivier


> 
> 	--yliu
> > 
> > #0  0x0000000000000000 in ?? ()
> > #1  0x0000000000423da2 in rte_mempool_ops_dequeue_bulk (n=1, obj_table=0x7fffffffd8e0, mp=0x7fe910fbd540) at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/dist
> > #2  __mempool_generic_get (flags=<optimized out>, cache=<optimized out>, n=<optimized out>, obj_table=<optimized out>, mp=<optimized out>)
> >     at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/distrib_upd/x86_64-native-linuxapp-gcc/include/rte_mempool.h:1296
> > #3  rte_mempool_generic_get (flags=<optimized out>, cache=<optimized out>, n=<optimized out>, obj_table=<optimized out>, mp=<optimized out>)
> >     at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/distrib_upd/x86_64-native-linuxapp-gcc/include/rte_mempool.h:1334
> > #4  rte_mempool_get_bulk (n=1, obj_table=0x7fffffffd8e0, mp=0x7fe910fbd540) at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/distrib_upd/x86_64-native-linuxapp
> > #5  rte_mempool_get (obj_p=0x7fffffffd8e0, mp=0x7fe910fbd540) at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/distrib_upd/x86_64-native-linuxapp-gcc/include/r
> > #6  rte_mbuf_raw_alloc (mp=0x7fe910fbd540) at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/distrib_upd/x86_64-native-linuxapp-gcc/include/rte_mbuf.h:761
> > #7  rte_pktmbuf_alloc (mp=0x7fe910fbd540) at /sonus/p4/ws/sodey/cmn_thirdparty.cloud_dev_5_1/Intel/DPDK/distrib_upd/x86_64-native-linuxapp-gcc/include/rte_mbuf.h:1046
> >   
> > >From the trace it looks like that the ops->dequeue is failing as the ops is not set properly.  
> > In the primary process I have done a rte_mempool_create with the flags passed as 0 (indicating mp_mc option). This should have taken care of setting the ops properly. Also the rte_pktmbuf_alloc calls in the primary does not give any issues.
> > Both the primary and secondary DPDK app code was working fine with 2.1 DPDK, but now when I am trying to link to the newer DPDK versions like 16.07/16.11, it is crashing. There is no changes done in the app code.
> > I do see that the complete rte_mempool code has been changed between 2.1 to 16.07 but could not  find any obvious reasons of the crash. Is my usage wrong or do we need to pass any new flag to make this work.
> > 
> > Did anyone faced similar issue or any help in this will be great for my debugging. Thanks in advance for the help.
> > 
> > --
> > Regards,
> > Souvik