Issue with Packet Memory Allocation – Double Allocation Without Freeing

Issue with Packet Memory Allocation – Double Allocation Without Freeing

[Jaiswal, Adesh]

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Hello everyone,

We are using memory allocation for packets in our DPDK-based application. However, we are observing a de-sync issue where, during debugging, we see logs indicating that a packet is allocated twice without being freed in between.
To diagnose the issue, we added logging at both the time of allocation and deallocation. From the logs, we noticed:

  *   The same memory address is allocated/shared twice without a corresponding free operation.
  *   This is causing inconsistencies in packet handling.
Our Questions:

  1.  Is this a known issue in DPDK 18.08?
  2.  Is there any existing patch or workaround available for this problem?
  3.  What could cause a scenario where a packet is allocated twice without freeing?
  4.  What debugging approaches or tools would you recommend for tracking such memory allocation inconsistencies?
Additional Details:

  *   DPDK version: DPDK 18.08.0 version 16
Would appreciate any insights or debugging tips from the community!

Thanks,
Adesh


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Re: Issue with Packet Memory Allocation – Double Allocation Without Freeing

[Stephen Hemminger]

On Wed, 26 Mar 2025 16:51:39 +0000
"Jaiswal, Adesh" <adesh.jaiswal@rakuten.com> wrote:

> Hello everyone,
> 
> We are using memory allocation for packets in our DPDK-based application. However, we are observing a de-sync issue where, during debugging, we see logs indicating that a packet is allocated twice without being freed in between.
> To diagnose the issue, we added logging at both the time of allocation and deallocation. From the logs, we noticed:
> 
>   *   The same memory address is allocated/shared twice without a corresponding free operation.
>   *   This is causing inconsistencies in packet handling.
> Our Questions:
> 
>   1.  Is this a known issue in DPDK 18.08?
>   2.  Is there any existing patch or workaround available for this problem?
>   3.  What could cause a scenario where a packet is allocated twice without freeing?
>   4.  What debugging approaches or tools would you recommend for tracking such memory allocation inconsistencies?
> Additional Details:
> 
>   *   DPDK version: DPDK 18.08.0 version 16
> Would appreciate any insights or debugging tips from the community!
> 
> Thanks,
> Adesh
> 

In the past, these have always been application not DPDK internal bugs.
Build with RTE_LIBRTE_MBUF_DEBUG and RTE_LIBRTE_ETHDEV_DEBUG might find something.

Remember mbuf's have ref counts.