Merge branch 'selftests-rds-log-collection-tap-compliance-and-cleanups'

Allison Henderson says:

====================
selftests: rds: Log collection, TAP compliance and cleanups

This series is a set of bug fixes and improvements for the rds
selftests.

Patch 1 bumps the kselftest timeout from 400s to 800s. The original
limit was developed against a lean config, but the kselftest harness
counts boot time and gcov log collection against the limit, so a
default config with gcov enabled needs more headroom.

Patch 2 corrects some typos in the run.sh USAGE string and removes an
unused "-g" flag.

Patch 3 silences a handful of pylint warnings in test.py: it adds a
module docstring, suppresses the warnings tied to the sys.path.append
import trick, marks the long lived tcpdump Popen with disable-next
consider-using-with, and drops unused exception variables from two
BlockingIOError except clauses.

Patch 4 adds a -t flag to run.sh so the timeout can be overridden
if needed.

Patch 5 adds a RDS_LOG_DIR environment variable that specifies where
logs should be stored, or skips log collection if left unset

Patch 6 adds a SUDO_USER environment variable that sets the user
for tcpdump --relinquish-privileges.  This avoid the permissions
drop that would leave pcaps empty on 9pfs since 9p does not
support chown

Patch 7 removes the initial tmp tcpdumps and instead saves the pcaps
directly to the logdir if it is set.

Patch 8 hoists the tcpdump shutdown into a helper and calls it from the
timeout signal handler so that the processes are properly terminated
and dumps are flushed

Patch 9 fixes gcov collection by ensuring debugfs is mounted, and
specifying the --root folder so that gcov can still find the kernel
source when it is run from the ksft test directory.

Patch 10 makes the test output TAP compliant so the kselftest runner
parses results correctly.
====================

Link: https://patch.msgid.link/20260504054143.4027538-1-achender@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>