[PATCH v2] lib/ethdev: fix segfault in secondary process by validating dev_private pointer

[Ivan Malov]

Hi Khadem,

On Wed, 23 Jul 2025, Khadem Ullah wrote:

> Please check v3 of this patch.

Checked. In the meantime, you're not overlooking to mark previous versions [1]
with status 'SUPERSEDED' in DPDK Patchwork, are you?

[1] https://patches.dpdk.org/project/dpdk/patch/20250723045022.1580829-1-14pwcse1224@uetpeshawar.edu.pk/

> 
> On Wed, Jul 23, 2025 at 5:19 PM Khadem Ullah <14pwcse1224 at uetpeshawar.edu.pk> wrote:
> 
> Secondary application not only breaking on device closing,
> it's also getting segfault when we do "show device info all" from secondary
> after primary closes:
> testpmd> show device info all
> ********************* Infos for device 0000:03:00.0 *********************
> Bus name: pci
> Bus information: vendor_id=15b3, device_id=101d
> Driver name: mlx5_pci
> Devargs:
> Connect to socket: 0
> Segmentation fault (core dumped)
> This patch prevents these crashes and it seems that these fixes should be in PMD along with the ethdev layer. Some more checks will be added in the next version to prevent "show device i
> nfo all" crash.
> 
> 
> On Wed, Jul 23, 2025 at 9:50 AM Khadem Ullah <14pwcse1224 at uetpeshawar.edu.pk> wrote:
>       In secondary processes, directly accessing 'dev->data->dev_private' can
>       cause a segmentation fault if the primary process has exited or if the
>       shared memory is no longer accessible.
>
>       This patch adds a safety check using rte_mem_virt2phy(), with an
>       unlikely() branch hint to minimize performance impact in the fast path.
>       This ensures 'dev_private' is still valid before accessing it.
>
>       Fixes: bdad90d12ec8 ("ethdev: change device info get callback to return int")
>       Cc: stable at dpdk.org
>
>       Signed-off-by: Khadem Ullah <14pwcse1224 at uetpeshawar.edu.pk>
>       ---
>        lib/ethdev/rte_ethdev.c | 7 +++++++
>        1 file changed, 7 insertions(+)
>
>       diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
>       index dd7c00bc94..ef5dc55f2e 100644
>       --- a/lib/ethdev/rte_ethdev.c
>       +++ b/lib/ethdev/rte_ethdev.c
>       @@ -4079,6 +4079,13 @@ rte_eth_dev_info_get(uint16_t port_id, struct rte_eth_dev_info *dev_info)
>
>               if (dev->dev_ops->dev_infos_get == NULL)
>                       return -ENOTSUP;
>       +       if (rte_eal_process_type() == RTE_PROC_SECONDARY &&
>       +               unlikely(rte_mem_virt2phy(dev->data->dev_private) == RTE_BAD_PHYS_ADDR)) {
>       +                       RTE_ETHDEV_LOG_LINE(ERR,
>       +                       "Secondary: dev_private not accessible (primary exited?)");
>       +                       rte_errno = ENODEV;
>       +                       return -rte_errno;
>       +       }
>               diag = dev->dev_ops->dev_infos_get(dev, dev_info);
>               if (diag != 0) {
>                       /* Cleanup already filled in device information */
>       --
>       2.43.0
> 
> 
> 
> --
> Engr. Khadem Ullah,
> Software Engineer,
> Dreambig Semiconductor Inc
> https://dreambigsemi.com/
> 
> 
> 
> --
> Engr. Khadem Ullah,
> Software Engineer,
> Dreambig Semiconductor Inc
> https://dreambigsemi.com/
> 
>