From: Jakub Kicinski kuba@kernel.org
[ Upstream commit ee3ae27721fb994ac0b4705b5806ce68a5a74c73 ]
The test currently modifies the HDS settings and doesn't restore them. This may cause subsequent tests to fail (or pass when they should not). Add defer()ed reset handling.
Link: https://patch.msgid.link/20250825175939.2249165-1-kuba@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
YES
- Fixes a real bug in the selftest: The test was mutating device HDS settings and not restoring them, which can make subsequent tests fail or pass incorrectly. The commit adds a robust, deferred cleanup to restore both HDS mode and threshold to their original values, directly addressing the issue described in the commit message.
- Adds targeted, low-risk cleanup helpers: - Introduces `_hds_reset()` to restore original settings captured before modification. It first tries resetting `tcp-data-split` to `"unknown"` (auto) and, if that doesn’t match the prior value, falls back to the exact original value; it also restores `hds-thresh` if it changed. See `tools/testing/selftests/drivers/net/hds.py:63`–81. - Adds `_defer_reset_hds()` which captures the current ring settings (if supported) and schedules `_hds_reset()` using the existing deferred cleanup mechanism. See `tools/testing/selftests/drivers/net/hds.py:84`–90. - This follows existing patterns used elsewhere in the selftests (e.g., explicit defers in iou-zcrx), increasing consistency across tests (cf. `tools/testing/selftests/drivers/net/hw/iou- zcrx.py:50`–54, 81–85, 112–116).
- Ensures cleanup runs even on failures: The selftest framework flushes the global defer queue after each subtest, so scheduled resets will execute regardless of exceptions or skips. See `tools/testing/selftests/net/lib/py/ksft.py:271`.
- Minimal, contained changes: Only test code is touched (no kernel or driver changes). The changes are small and localized to `tools/testing/selftests/drivers/net/hds.py`.
- Defensive behavior and broad compatibility: - `_defer_reset_hds()` only schedules a reset if the device reports `hds-thresh` or `tcp-data-split` support and quietly ignores `NlError` exceptions (graceful on older kernels/drivers that don’t support these attributes), see `tools/testing/selftests/drivers/net/hds.py:84`–90. - Individual setters still check capabilities and skip when features aren’t supported (e.g., `get_hds`, `get_hds_thresh`), maintaining current skip behavior.
- Systematic application at mutation points: The new `_defer_reset_hds()` is invoked at the start of each function that modifies HDS-related state: - `set_hds_enable()` at `tools/testing/selftests/drivers/net/hds.py:93`–99. - `set_hds_disable()` at `tools/testing/selftests/drivers/net/hds.py:111`–119. - `set_hds_thresh_zero()` at `tools/testing/selftests/drivers/net/hds.py:129`–137. - `set_hds_thresh_random()` at `tools/testing/selftests/drivers/net/hds.py:147`–156`. - `set_hds_thresh_max()` at `tools/testing/selftests/drivers/net/hds.py:178`–186`. - `set_hds_thresh_gt()` at `tools/testing/selftests/drivers/net/hds.py:196`–205`. - `set_xdp()` when it changes `tcp-data-split` from `'enabled'` to `'unknown'` at `tools/testing/selftests/drivers/net/hds.py:217`–223`. - Existing explicit defer in `enabled_set_xdp()` remains (restores `'unknown'`), see `tools/testing/selftests/drivers/net/hds.py:235`–239.
- No architectural or behavioral risk to the kernel: The change affects only Python selftests, improving test isolation and reliability. It does not introduce new features or alter kernel behavior.
Given it is a clear test fix that prevents cross-test contamination, is self-contained, low-risk, and improves the reliability of the selftest suite, it meets stable backport criteria.
tools/testing/selftests/drivers/net/hds.py | 39 ++++++++++++++++++++++ 1 file changed, 39 insertions(+)
diff --git a/tools/testing/selftests/drivers/net/hds.py b/tools/testing/selftests/drivers/net/hds.py index 7c90a040ce45a..a2011474e6255 100755 --- a/tools/testing/selftests/drivers/net/hds.py +++ b/tools/testing/selftests/drivers/net/hds.py @@ -3,6 +3,7 @@
import errno import os +from typing import Union from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_raises, KsftSkipEx from lib.py import CmdExitFailure, EthtoolFamily, NlError from lib.py import NetDrvEnv @@ -58,7 +59,39 @@ def get_hds_thresh(cfg, netnl) -> None: if 'hds-thresh' not in rings: raise KsftSkipEx('hds-thresh not supported by device')
+ +def _hds_reset(cfg, netnl, rings) -> None: + cur = netnl.rings_get({'header': {'dev-index': cfg.ifindex}}) + + arg = {'header': {'dev-index': cfg.ifindex}} + if cur.get('tcp-data-split') != rings.get('tcp-data-split'): + # Try to reset to "unknown" first, we don't know if the setting + # was the default or user chose it. Default seems more likely. + arg['tcp-data-split'] = "unknown" + netnl.rings_set(arg) + cur = netnl.rings_get({'header': {'dev-index': cfg.ifindex}}) + if cur['tcp-data-split'] == rings['tcp-data-split']: + del arg['tcp-data-split'] + else: + # Try the explicit setting + arg['tcp-data-split'] = rings['tcp-data-split'] + if cur.get('hds-thresh') != rings.get('hds-thresh'): + arg['hds-thresh'] = rings['hds-thresh'] + if len(arg) > 1: + netnl.rings_set(arg) + + +def _defer_reset_hds(cfg, netnl) -> Union[dict, None]: + try: + rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}}) + if 'hds-thresh' in rings or 'tcp-data-split' in rings: + defer(_hds_reset, cfg, netnl, rings) + except NlError as e: + pass + + def set_hds_enable(cfg, netnl) -> None: + _defer_reset_hds(cfg, netnl) try: netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'enabled'}) except NlError as e: @@ -76,6 +109,7 @@ def set_hds_enable(cfg, netnl) -> None: ksft_eq('enabled', rings['tcp-data-split'])
def set_hds_disable(cfg, netnl) -> None: + _defer_reset_hds(cfg, netnl) try: netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'disabled'}) except NlError as e: @@ -93,6 +127,7 @@ def set_hds_disable(cfg, netnl) -> None: ksft_eq('disabled', rings['tcp-data-split'])
def set_hds_thresh_zero(cfg, netnl) -> None: + _defer_reset_hds(cfg, netnl) try: netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': 0}) except NlError as e: @@ -110,6 +145,7 @@ def set_hds_thresh_zero(cfg, netnl) -> None: ksft_eq(0, rings['hds-thresh'])
def set_hds_thresh_random(cfg, netnl) -> None: + _defer_reset_hds(cfg, netnl) try: rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}}) except NlError as e: @@ -140,6 +176,7 @@ def set_hds_thresh_random(cfg, netnl) -> None: ksft_eq(hds_thresh, rings['hds-thresh'])
def set_hds_thresh_max(cfg, netnl) -> None: + _defer_reset_hds(cfg, netnl) try: rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}}) except NlError as e: @@ -157,6 +194,7 @@ def set_hds_thresh_max(cfg, netnl) -> None: ksft_eq(rings['hds-thresh'], rings['hds-thresh-max'])
def set_hds_thresh_gt(cfg, netnl) -> None: + _defer_reset_hds(cfg, netnl) try: rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}}) except NlError as e: @@ -178,6 +216,7 @@ def set_xdp(cfg, netnl) -> None: """ mode = _get_hds_mode(cfg, netnl) if mode == 'enabled': + _defer_reset_hds(cfg, netnl) netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'unknown'})