Re: [PATCH v3 0/9] net/memif: lifecycle fixes and unit test

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 16 Oct 2026 16:15:48 +0200
Sriram Yagnaraman <sriram.yagnaraman@ericsson.com> wrote:

> This series fixes a set of error-path and lifecycle bugs in the memif
> PMD and adds a unit test for the driver.
> 
> The first eight patches are fixes:
> 
>  - guard eth_memif_tx() against an empty burst (nb_pkts == 0);
>  - close file descriptor 0 instead of leaking it;
>  - do not close the EAL-owned memseg fd in zero-copy mode;
>  - free the MAC address allocated during probe on failure;
>  - unwind a partially-created device on create failure;
>  - refuse connections on a stopped server so it does not come up on a
>    stopped port;
>  - disconnect on close so a stopped server's control channel is not
>    leaked, and make memif_disconnect() safe on a never-started device;
>  - fix eth_memif_tx_zc() returning 65535 on an invalid interrupt fd.
> 
> The last patch adds a memif PMD unit test (app/test, memif_pmd_autotest):
> a server/client vdev pair over a loopback socket covering dev_info, link
> state, stats, single-segment loopback (slow and fast path), multi-segment
> loopback across a ring wrap, stop/start reconnect, empty Tx burst, close
> without stop, and a stopped server refusing a peer.
> 
> Verified: memif_pmd_autotest passes 11/11; each commit builds with
> -Dwerror=true; check-git-log and checkpatch are clean.
> 
> Thanks to Stephen Hemminger and the ai-code-review bot for the reviews
> that shaped this series.
> 
> v3:
>  - Rebase on main, picking up rte_intr_fd_close() from
>    d9191f684c ("interrupts: add helpers to close FD"): patch 2 keeps
>    only the owned-fd ">= 0" fixes not superseded by that helper, and
>    patch 7 keeps the NULL-queue guards above the rte_intr_fd_close()
>    calls.
>  - New patch 6: refuse connections on a stopped server. The started-
>    then-stopped case is the actual trigger for the control-channel
>    leak; dev_stop now sets ETH_MEMIF_FLAG_DISABLED. (v2 patch 6/7
>    described this as never-started, which was wrong.)
>  - Patch 7 (disconnect on close): reword to the real trigger and keep
>    the close-time disconnect as a backstop.
>  - Patch 3 (memseg fd): also stop closing the EAL-owned fd in
>    memif_connect(), not only memif_free_regions().
>  - Test: new test_memif_stopped_server_rejects_peer covering patch 6
>    (fails without it); reword close-without-stop to what it actually
>    covers (the NULL-queue skip); verify the full fast-path payload.
> 
> v2:
>  - P1: correct Fixes tag (Tx fast path, not original driver); move the
>    empty-burst check after the ring == NULL block.
>  - P2: split the memseg-fd change into its own patch rather than
>    widening the check to ">= 0".
>  - P4 (MAC leak): document the secondary -1 -> -ENOMEM change.
>  - P5 (unwind): add Fixes: multi-process support.
>  - New patch: fix eth_memif_tx_zc() bogus Tx count on invalid fd.
>  - Test: add to MAINTAINERS; return TEST_FAILED (not SKIPPED) on probe
>    failure; add a default-bsize pair to cover the Tx fast path; set
>    ring size via rsize and fix the stale comments.
> 
> Sriram Yagnaraman (9):
>   net/memif: guard against empty Tx burst
>   net/memif: close file descriptor zero
>   net/memif: do not close EAL-owned memseg file descriptor
>   net/memif: fix MAC address leak on probe failure
>   net/memif: unwind partial device on create failure
>   net/memif: refuse connection on stopped device
>   net/memif: disconnect on device close
>   net/memif: fix bogus Tx count on invalid interrupt FD
>   test/memif: add memif PMD unit test
> 
>  MAINTAINERS                       |   1 +
>  app/test/meson.build              |   1 +
>  app/test/test_pmd_memif.c         | 751 ++++++++++++++++++++++++++++++
>  drivers/net/memif/memif_socket.c  |  10 +-
>  drivers/net/memif/rte_eth_memif.c |  76 ++-
>  5 files changed, 812 insertions(+), 27 deletions(-)
>  create mode 100644 app/test/test_pmd_memif.c
> 


Still see warnings from AI

v3 applies to main (26.11-rc1) and every commit builds with
-Dwerror=true. Not run. The v2 comments are addressed. 6/9 fixes the
stopped-server case at the source, and the close test now covers what
its comment says.


[PATCH v3 7/9] net/memif: disconnect on device close

Info: the commit message describes the tree before 6/9. With 6/9
applied first, dev_stop does set ETH_MEMIF_FLAG_DISABLED, so "dev_stop
does not set it again ... memif_msg_receive_init() still accepts a
peer" is no longer true at this commit. Suggest:

  Before the previous patch, a server that was started and then
  stopped still accepted a peer and held a live pmd->cc at close.
  Call memif_disconnect() from close as a backstop for an init that
  races with stop.


[PATCH v3 9/9] test/memif: add memif PMD unit test

Warning: test_memif_stopped_server_rejects_peer() passes only by
timing out, so it always burns the full wait_for_link_pair() window
(CONNECT_TRIES * CONNECT_DELAY_US = 5s). memif_pmd_autotest is a fast
test with a 10s meson timeout, and that budget also has to cover EAL
init and the other handshakes, under ASan too. Use a short window for
the negative check:

	static int
	wait_for_link_pair_tries(int p0, int p1, int tries)
	...

	#define REJECT_TRIES 10	/* 1s */

	ret = wait_for_link_pair_tries(sport, cport, REJECT_TRIES);

Info: the commit message does not list the fast-path loopback or the
stopped-server test.