From 8319dadcbd8121d94f72332ab926de7f69d9b801 Mon Sep 17 00:00:00 2001 From: Kunwu Chan Date: Mon, 29 Jun 2026 07:46:44 -0700 Subject: [PATCH] selftests/damon: prevent cross-context state pollution in DamonCtx Patch series "selftests/damon: misc fixes for test bugs", v3. This series fixes several bugs in the DAMON selftests. Most are trivial but makes test output wrong or even silently pass the one test case for 'avail_operation' file existence check. Patch 1 fixes mutable default arguments in DamonCtx.__init__() that cause state to leak between test instances. Patch 2 fixes wrong operator precedence and join TypeError in damos_tried_regions.py. Patch 3 fixes several wrong strings that produce dead elif branches, skipped file existence checks, and broken dict key lookups. This patch (of 3): DamonCtx.__init__() uses mutable default values for monitoring_attrs, targets, and schemes. In Python these are evaluated once at function definition time, so multiple DamonCtx instances can unintentionally share the same lists and DamonAttrs instance. Replace the mutable defaults with None sentinels and initialize the objects when needed. Link: https://lore.kernel.org/20260629144648.134092-1-sj@kernel.org Link: https://lore.kernel.org/20260601032314.424013-2-kunwu.chan@linux.dev Link: https://lore.kernel.org/20260629144648.134092-2-sj@kernel.org Co-developed-by: Wang Lian Signed-off-by: Wang Lian Signed-off-by: Kunwu Chan Signed-off-by: SJ Park Reviewed-by: SJ Park Cc: Kunwu Chan Cc: Wang Lian Signed-off-by: Andrew Morton --- tools/testing/selftests/damon/_damon_sysfs.py | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/damon/_damon_sysfs.py b/tools/testing/selftests/damon/_damon_sysfs.py index 8b12cc048440..2f6f2699db25 100644 --- a/tools/testing/selftests/damon/_damon_sysfs.py +++ b/tools/testing/selftests/damon/_damon_sysfs.py @@ -624,17 +624,23 @@ class DamonCtx: pause = None idx = None - def __init__(self, ops='paddr', monitoring_attrs=DamonAttrs(), targets=[], - schemes=[], pause=False): + def __init__(self, ops='paddr', monitoring_attrs=None, targets=None, + schemes=None, pause=False): self.ops = ops + if monitoring_attrs is None: + monitoring_attrs = DamonAttrs() self.monitoring_attrs = monitoring_attrs self.monitoring_attrs.context = self + if targets is None: + targets = [] self.targets = targets for idx, target in enumerate(self.targets): target.idx = idx target.context = self + if schemes is None: + schemes = [] self.schemes = schemes for idx, scheme in enumerate(self.schemes): scheme.idx = idx