linux.git/tools/testing/selftests/net/lib/py/utils.py, branch v7.2-rc2

selftests: net: bump default cmd() timeout to 20 seconds

2026-06-30T23:54:37+00:00

We always used 5 sec as the default command timeout. But soon after
it was introduced, David effectively made us ignore the timeout
(it was passed to process.communicate() as the wrong argument).
Gal recently fixed that, but turns out the 5 sec is not enough
for a lot of tests and setups. The fix caused regressions.

In particular running reconfig commands (e.g. XDP attach) on mlx5
with 32 rings and 9k MTU, on a heavily-debug-enabled kernel takes
more than 5 sec. The XDP installation command will time out after
5 sec but since the sleeps in the kernel are non interruptible
the command finishes anyway, leaving the XDP program attached,
but with non-zero exit code. defer()ed cleanups are not installed,
breaking the environment for subsequent tests.

Since "install XDP" is a pretty normal command a "point fix"
does not seem appropriate. 32 rings is a fairly reasonable
config, too, so we should just increase the timeout to 20 sec.

There's no real reason behind the value of 20.

Fixes: 1cf270424218 ("net: selftest: add test for netdev netlink queue-get API")
Fixes: f0bd19316663 ("selftests: net: fix timeout passed as positional argument to communicate()")
Reviewed-by: Pavan Chebbi 
Acked-by: Breno Leitao 
Reviewed-by: Nimrod Oren 
Link: https://patch.msgid.link/20260629233348.2145841-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

selftests: drv-net: add userns devmem RX test

2026-06-06T01:10:31+00:00

Add userns_devmem.py, which mirrors nk_devmem.py but places the netkit
guest in a netns whose owning user_ns is non-init. ncdevmem is ran there
via nsenter so the bind-rx call is issued with creds that hold
CAP_NET_ADMIN only in the child user_ns.

Without the preceding GENL_UNS_ADMIN_PERM patch the test fails at
bind-rx with EPERM, but with the patch the transfer completes and tests
pass.

Signed-off-by: Bobby Eshleman 
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260602-nl-prov-v2-2-ad721142c641@meta.com
Signed-off-by: Jakub Kicinski

selftests: net: py: add tc utility

2026-05-06T01:15:29+00:00

Add a wrapper similar to existing ip, ethtool, ... commands.

Tc takes a slightly different syntax. Account for that.

The first user is the next patch in this series, converting so_txtime
to drv-net. Pacing offload is supported by selected qdiscs only.

Signed-off-by: Willem de Bruijn 
Link: https://patch.msgid.link/20260504174056.565319-3-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski

selftests: net: py: support cmd verifying expected failure

2026-05-06T01:15:29+00:00

Support negative tests, where cmd raises an exception if the command
succeeded.

Add optional argument expect_fail to cmd and bkg. Where fail fails the
test on unexpected error, expect_fail fails it on unexpected success.

Both fail on negative return code. Python subprocess may set a
negative return code on process crash or timeout. Those are never
anticipated failures.

Signed-off-by: Willem de Bruijn 
Link: https://patch.msgid.link/20260504174056.565319-2-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski

selftests: net: py: give bpftrace more time to start

2026-03-17T02:26:37+00:00

After commit under Fixes debug runners in the CI hit the following:

  # subprocess.TimeoutExpired: Command '['bpftrace', '-f', 'json', '-q', '-e', 'kprobe:netpoll_poll_dev { @hits = count(); } interval:s:10 { exit(); }']' timed out after 15 seconds
  # # Exception| net.lib.py.ksft.KsftFailEx: bpftrace failed to run!?: {}

in netpoll_basic.py >10% of the time. Let's give bpftool more time
to start, it can take a while on a debug kernel.

Fixes: 82562972b854 ("selftests: net: pass bpftrace timeout to cmd()")
Reviewed-by: Breno Leitao 
Reviewed-by: Petr Machata 
Reviewed-by: Nimrod Oren 
Link: https://patch.msgid.link/20260315160038.3187730-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

selftests: net: fix timeout passed as positional argument to communicate()

2026-03-12T02:11:40+00:00

The cited commit refactored the hardcoded timeout=5 into a parameter,
but dropped the keyword from the communicate() call.
Since Popen.communicate()'s first positional argument is 'input' (not
'timeout'), the timeout value is silently treated as stdin input and the
call never enforces a timeout.

Pass timeout as a keyword argument to restore the intended behavior.

Reviewed-by: Nimrod Oren 
Signed-off-by: Gal Pressman 
Link: https://patch.msgid.link/20260310115803.2521050-3-gal@nvidia.com
Signed-off-by: Jakub Kicinski

selftests: net: pass bpftrace timeout to cmd()

2026-03-12T02:11:36+00:00

The bpftrace() helper configures an interval based exit timer but does
not propagate the timeout to the cmd object, which defaults to 5
seconds. Since the default BPFTRACE_TIMEOUT is 10 seconds, cmd.process()
always raises a TimeoutExpired exception before bpftrace has a chance to
exit gracefully.

Pass timeout+5 to cmd() to allow bpftrace to complete gracefully.

Note: this issue is masked by a bug in the way cmd() passes timeout,
this is fixed in the next commit.

Reviewed-by: Nimrod Oren 
Signed-off-by: Gal Pressman 
Link: https://patch.msgid.link/20260310115803.2521050-2-gal@nvidia.com
Signed-off-by: Jakub Kicinski

selftests: net: py: Add rand_ports helper method

2026-02-26T03:42:02+00:00

Certain tests need a unique set of ports. Successive calls to the
existing rand_port method may return a duplicate port, resulting in test
flakiness. The new helper keeps sockets open while building a list of
ephemeral ports, thus the kernel enforces their uniqueness.

Signed-off-by: Dimitri Daskalakis 
Link: https://patch.msgid.link/20260224224659.1507082-2-dimitri.daskalakis1@gmail.com
Signed-off-by: Jakub Kicinski

selftests: net: py: add cmd info for ksft_wait failure

2026-02-25T02:25:29+00:00

Gal recently complained:

  When [ksft_wait failure] happens, the test fails with a cryptic
  message:
    # Exception| Exception: Did not receive ready message

Let's try to include the stdout/stderr of the command we tried
to start. E.g. for cmd("false", ksft_wait=True):

    # Exception| lib.py.utils.CmdInitFailure: Did not receive ready message
    # Exception| CMD: false
    # Exception|   EXIT: 1

We need to factor out _process_terminate() otherwise the exit
path may try to write to already disconnected self.ksft_term_fd.

Reviewed-by: Petr Machata 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20260223202633.4126087-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski

selftests: net: py: use repr(cmd) for failure exceptions

2026-02-25T02:25:29+00:00

Reuse repr(cmd) instead of manually formatting a similar string.

Before:
  # Exception| lib.py.utils.CmdExitFailure: Command failed: false
  # Exception| STDOUT: b''
  # Exception| STDERR: b''

After:
  # Exception| lib.py.utils.CmdExitFailure: Command failed
  # Exception| CMD: false
  # Exception|   EXIT: 1

Reviewed-by: Petr Machata 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20260223202633.4126087-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski