[PATCH] [PATCH v3] lib/ethdev: fix segfault in secondary process by validating dev_private pointer

[Khadem Ullah]

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.

Secondary application not only breaking on device closing,
but also getting segfault when we do "show device info all" from secondary
after primary closes.

This patch adds safety checks while 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 | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index dd7c00bc94..343e156a4f 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 */
@@ -4307,7 +4314,13 @@ rte_eth_macaddr_get(uint16_t port_id, struct rte_ether_addr *mac_addr)
 			port_id);
 		return -EINVAL;
 	}
-
+	if (rte_eal_process_type() == RTE_PROC_SECONDARY &&
+		(dev->data->mac_addrs == NULL)) {
+			RTE_ETHDEV_LOG_LINE(ERR,
+			"Secondary: dev_private not accessible (primary exited?)");
+			rte_errno = ENODEV;
+			return -rte_errno;
+	}
 	rte_ether_addr_copy(&dev->data->mac_addrs[0], mac_addr);
 
 	rte_eth_trace_macaddr_get(port_id, mac_addr);
-- 
2.43.0