From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2197A308F23 for ; Tue, 4 Aug 2026 04:21:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785817278; cv=none; b=jYqjEamhu+BAkrz9kIxz/Adrfnbnq3r+vM7xIAn/BsYrEI35wZUXOiPwP00ZWMDfgH0vAnq07eK8rwzdrA0f+Q9z51YxUSTTZu42rFcNSpgAgvU/VmjbC8uPXlUnXryi+F67PeqXC4HO4NYUK2JectosmQ+Okjm8sHpcGJbcPDs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785817278; c=relaxed/simple; bh=3hjC5tQGZaEndcSr0kknDCtu9P8kownNQ1aiLVGYqqE=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=oi5ukpriIb6rRp+0g7iGbp1ezKS29etqLZM5vz6fZaIh7Z75fiIkhPb92k15Q51v5ZuUoExRPpd43vkanRmBgn2JS/jrXczJnf8WN1JLxglOkA7nAGZmYNTsFTaUWkacVKQhk5z32DTI9LxQi7nzOoz2pd8NNd6iV7EbVpt3GCM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--wfelipe.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=eyJdLRvS; arc=none smtp.client-ip=209.85.216.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--wfelipe.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eyJdLRvS" Received: by mail-pj1-f71.google.com with SMTP id 98e67ed59e1d1-38e5a616d07so4293896a91.2 for ; Mon, 03 Aug 2026 21:21:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785817275; x=1786422075; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:mime-version:date:from :to:cc:subject:date:message-id:reply-to:content-type; bh=1EHxIenGghG1qcflV4x5EPNN6hTPv19+mMdXwN3odLs=; b=eyJdLRvSzL8o+XsyJv3kqOibISS4yrnT7HidF94M/kA7W1pVrMHHEGmkmAllvpsClg Lb3ZIksPw5kP4n0hpc8xTekVE5yhzoxv2I7K9Vx68+4i34nZTtXyCq9GOH/SKRHOm9fS O1e23yR7B7YV4a8C2R5qzrEM9tV6heKWuh/mwaFyHkZoRJiiAZadZHa6I1yB5VpNLLNg rZlWVKUMG390MLohJFCS4qrHmPWHd85bnwdy+JPHz58UQLnFfhtRyfdPKnW3FWOz5CJx 9LWyxrBpYf/4gk7PnnVaTsuHObxJ8DGJWuOb/FsTfV3ahwvfQKmy91Y+r6gDpPDKRzCu 28eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785817275; x=1786422075; h=content-type:cc:to:from:subject:message-id:mime-version:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=1EHxIenGghG1qcflV4x5EPNN6hTPv19+mMdXwN3odLs=; b=WQqKrlJr3ohy8/KaFOAd43RnIb2SfqP5Qb2RbNnuXe4G7adox+M1pVcw5fMdIaPD/H jA0eqt5SfsDHKvny4Ewqlax2UGYTGNGIf2U0o0kybW1/OET6hm2zcqRq3Y6vU7HnePYk p1/SEenwJinNV5lU2qqhdF+qZXznIVkrMk42nbZ/jLG1Z/NElAhZyL4OR+Ivx/9taiWJ SKD5wGDx5vNuKDHh/9CH6gHU9i7VehKEULMfMmhXY+Vk2CVgXhT+wozVMeavcS2WQ2ZT jE5jQe3v8/ZNNpi4cofZLYq6OuVFCQcFGdLIYcl1MGipyOxqUqVKuCnZMs3EOPxOus7X nFsA== X-Forwarded-Encrypted: i=1; AHgh+Rq40JnV/hVH0JOilayJXBQFceVkwj8VwP5mh+iexiYDV+3E/TQf/oNHY9I8WKYHb8s69U96LOwF@vger.kernel.org X-Gm-Message-State: AOJu0Yx0y4k9TDOLm3QTOpOGdLqDue35w30mvSUodbBMfAujduVWELY2 hH4rCz0R2SvvNLY/bljaR5Tha9h8VTs/jSTqarv4m/aYbBFmyzGiZlFyajv8w602UrGiNlgsbZL eIxnvXu75VQ== X-Received: from pjot9.prod.google.com ([2002:a17:90a:9509:b0:38e:1db:751c]) (user=wfelipe job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:17c5:b0:38e:7168:281 with SMTP id 98e67ed59e1d1-38fbc424a3dmr10661157a91.10.1785817275127; Mon, 03 Aug 2026 21:21:15 -0700 (PDT) Date: Tue, 4 Aug 2026 04:20:43 +0000 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.571.g244d577d93-goog Message-ID: <20260804042053.56940-1-wfelipe@google.com> Subject: [PATCH 0/2] selftests/cgroup: test_zswap: fix single-core flakes From: Wilson Felipe Pereira To: Johannes Weiner , Yosry Ahmed , Nhat Pham , Chengming Zhou , Tejun Heo , "=?UTF-8?q?Michal=20Koutn=C3=BD?=" , Shuah Khan Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org, Wilson Felipe Pereira Content-Type: text/plain; charset="UTF-8" When running the cgroup zswap selftests on a single-core VM (-smp 1) with 4GB of RAM, test_zswap_writeback and test_no_kmem_bypass reliably fail on the initial run after boot due to timing and asynchronous tasks not completed. This 2-patch series fixes both initial-run failures: * Patch 1 fixes an EBUSY race in test_zswap_writeback() where writing "+memory" to cgroup.subtree_control collides with the kernel's asynchronous RCU removal of dead child tasks from cgroup.procs. * Patch 2 fixes an implicit unsigned integer promotion bug in test_no_kmem_bypass() where a small negative delta becomes large when compared to an unsigned size_t threshold. Both tests now reliably pass on the initial run after cold boot on -smp 1 VMs. Wilson Felipe Pereira (2): selftests/cgroup: test_zswap: retry subtree_control write on EBUSY in test_zswap_writeback selftests/cgroup: test_zswap: fix implicit unsigned promotion bug in test_no_kmem_bypass tools/testing/selftests/cgroup/test_zswap.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) -- 2.55.0.571.g244d577d93-goog