When a secondary process detects primary process has exited and calls
eal_cleanup a warning message is generated.

Primary: testpmd
# dpdk-testpmd  -l 0-3  --vdev=net_tap0 -- -i

testpmd> start
...
testpmd> quit


Secondary: dumpcap
# dpdk-dumpcap
File: /tmp/dpdk-dumpcap_0_net_tap0_20250722081556.pcapng
Capturing on 'net_tap0'
Packets captured: 34 Primary process is no longer active, exiting...
EAL: failed to send to (/var/run/dpdk/rte/mp_socket) due to No such file or
directory
EAL: Fail to send request /var/run/dpdk/rte/mp_socket:mp_pdump
PDUMP: pdump_prepare_client_request(): client request for pdump enable/disable
failed
EAL: failed to send to (/var/run/dpdk/rte/mp_socket) due to No such file or
directory
EAL: Cannot send message to primary

Dumpcap is doing the right thing and detecing, the problem is internal to EAL.