Here is a little series which helped me identify a multi segment issue. Hope it can help others.
The difference since the RFC patches I sent some time ago is that, rather than force the user to build the dpdk with CONFIG_RTE_LIBRTE_MBUF_DEBUG enabled, it uses rx/tx callbacks to apply checks on the mbufs. This is not perfect, since when an invalid mbuf is detected, we try to free it and a crash is possible at this time (depends on what went wrong). On the rx side, this is better than let this packet go through the application and we end up with harder to identify issues. On the tx side, this is more about validating that the application did not break the mbuf before passing it to the driver. Example: ./testpmd -l 2,14 --socket-mem 2048,0 -w 0000:03:00.0 -w 0000:03:00.1 -- -i [...] testpmd> port stop all testpmd> port config all sanity_check rx+tx testpmd> port config all scatter on testpmd> port start all Configuring Port 0 (socket 0) Port 0: F4:E9:D4:ED:B4:06 Configuring Port 1 (socket 0) Port 1: F4:E9:D4:ED:B4:07 Checking link statuses... Done testpmd> port config mtu 0 9000 testpmd> port config mtu 1 9000 testpmd> start testpmd: invalid rx mbuf on port 1 queue 0: data length too big in mbuf segment testpmd> set verbose 1 Change verbose level from 0 to 1 dump mbuf at 0x7f48db9fa740, iova=2291fa7c0, buf_len=2176 pkt_len=8014, ol_flags=180, nb_segs=4, in_port=1 segment at 0x7f48db9fa740, data=0x7f48db9fa840, data_len=2112 segment at 0x7f48db9fb080, data=0x7f48db9fb180, data_len=2112 segment at 0x7f48db9fb9c0, data=0x7f48db9fbac0, data_len=2112 segment at 0x7f48db9fc300, data=0x7f48db9fc400, data_len=1678 testpmd: invalid rx mbuf on port 1 queue 0: data length too big in mbuf segment -- David Marchand David Marchand (3): mbuf: add sanity checks on segment metadata mbuf: add a non fatal sanity check helper app/testpmd: add sanity checks on received/sent packets app/test-pmd/cmdline.c | 63 ++++++++++++++ app/test-pmd/config.c | 23 +++++ app/test-pmd/parameters.c | 7 ++ app/test-pmd/testpmd.c | 123 +++++++++++++++++++++++++++ app/test-pmd/testpmd.h | 9 ++ lib/librte_mbuf/Makefile | 2 + lib/librte_mbuf/meson.build | 2 + lib/librte_mbuf/rte_mbuf.c | 71 ++++++++++++---- lib/librte_mbuf/rte_mbuf.h | 23 +++++ lib/librte_mbuf/rte_mbuf_version.map | 6 ++ 10 files changed, 312 insertions(+), 17 deletions(-) -- 2.17.1
