From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793962573; b=A2C3Wzcxz2Q74AIPwpSegK9AV9O9hQz4G25WkOoCW/cPi/hboBPCtjLvdR+Gr9y0hrta Wdsv02ZeD2j1WmEF691DC92pRZ50OcZI+rPT1mVoRbhou6zbt5U1shsRkkntg7nl2gqas ML4l1fbpPndx6Gqmo72L0BNklCD8XAS9kKOt5DBqiKaZCvSf5G3lXXmv/VcjN879AXfG1 kS2SqLIHCa0J+BRHPF+PrjqHbXChjRZZRgcNbDI6md5+pbXBeMpOTIXbME9UitpgIlPxs xpi3pkm1kktPjFMJDdb/T+bHq9hRDIxI38IVtHKftVbnUN6p7SJUj4Vj7+38Q3kshpg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793962573; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-Id: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=B80Ru/+QQZrR8+3BTuaBiUO91fsH99eqxOSlWVO284w=; b=TWNS6KTrrcGG8NXS4bjBTTfZwZI8/e7wCKvyRlJss8vNUZctZF8Ip+KBL24YTGzJxj8n cq41kwN5S75uJypSWudjVEnvUyN97MlmncDkA571mTm0GXr7opWF/lOQSSpvbSafvGDPo Gqeh4hxKD6UJ2D64nlC3o3KEUk5ptf657ka/vkWLeYFDTdeaOTOoXpAUz8CCwr8yZs6oi F9+Fp6vO2Ux90zPhDdqJfMv/2AxD80SK7jUVYVjra/BTdX2Zy6rT7/ta8r9W3wdrQdTx0 mwII04gxMzJVc3HwGyDl5pAJjYXOFn0Sw+6tgBrjNn4xWxx1IvL0NznFNKqwcelgVVQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=VOE9R7wp; arc=none smtp.remote-ip=95.215.58.172 Received: from mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7B12606D80B for ; Fri, 6 Nov 2026 10:56:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E7B12606D80B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=VOE9R7wp X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=PUjvcPrNp9l3japZeaonwrQrwoa398mhSxLN/CbO7N0=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793962570; v=1; x=1794567370; b=VOE9R7wpapU4bEnEd8BgSNgkGTfWaJnXebL/NgEyPvyc06x4zKdydE6O7zXyibuWg5SNs4nS 1+VhJNI9zUUovEtF5BnBwMZ+JhJ8eR6tc0cTu4C8yvssK/xJ3tv62bXdmx3EG4yIIOeYBBk5A6l 2aYDO6MoVoF2uXsRoSGFa+nM= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 5cfb5cbc1ecd42f4; Fri, 06 Nov 2026 10:56:08 +0000 X-Mizu-Trace-ID: 5cfb5cbc1ecd42f4 X-Migadu-Flow: FLOW_OUT From: Ridong Chen To: Waiman Long , Tejun Heo , Johannes Weiner , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Shuah Khan Cc: Ridong Chen , Chen Ridong , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Sashiko , Guopeng Zhang , Ridong Chen Subject: [PATCH v2 1/4] cgroup/cpuset: Reset partition data when an invalid partition stays invalid Date: Fri, 6 Nov 2026 18:55:35 +0800 Message-Id: <20261106105538.2915492-2-ridong.chen@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261106105538.2915492-1-ridong.chen@linux.dev> References: <20261106105538.2915492-1-ridong.chen@linux.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ridong Chen When cpuset.cpus or cpuset.cpus.exclusive of a partition root is changed, update_cpumask() and update_exclusive_cpumask() copy the new effective_xcpus computed for the trial cpuset into the cpuset, and call reset_partition_data() only if the partition was valid before and is invalid now: if ((old_prs > 0) && !is_partition_valid(cs)) reset_partition_data(cs); An invalid partition root (old_prs < 0) that stays invalid is not covered. Its effective_xcpus is then left with the trial value, which is computed from user_xcpus() and so falls back to cpuset.cpus when cpuset.cpus.exclusive is cleared. As an invalid partition root does not own any exclusive CPUs, and rm_siblings_excl_cpus() treats a non-empty effective_xcpus of a sibling without cpuset.cpus.exclusive as owned, those CPUs can then no longer be claimed by a sibling: # A1: cpuset.cpus=2-3, cpuset.cpus.exclusive=2-3, root, with tasks # offline CPUs 2-3 -> A1 becomes invalid echo > A1/cpuset.cpus.exclusive cat A1/cpuset.cpus.exclusive.effective # 2-3, expected empty echo 3 > B1/cpuset.cpus.exclusive # -EINVAL Reset the partition data whenever the cpuset is a partition root, valid or not, and ends up invalid. As effective_xcpus may be cleared by that, also force update_cpumasks_hier() to update the subtree, so that the effective_xcpus of the descendants doesn't keep the released CPUs. Add test cases for it. Fixes: de9f15e21c55 ("cpuset: use parse_cpulist for setting cpus.exclusive") Fixes: c5866c9a007d ("cpuset: refactor CPU mask buffer parsing logic") Reported-by: Sashiko Link: https://sashiko.dev/#/patchset/20261101114206.2434398-1-ridong.chen%40linux.dev?part=15 Signed-off-by: Ridong Chen --- kernel/cgroup/cpuset.c | 10 ++++++++-- tools/testing/selftests/cgroup/test_cpuset_prs.sh | 6 ++++++ 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 3052413e41e7..cf38e8708ddd 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2607,8 +2607,11 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, spin_lock_irq(&callback_lock); cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); cpumask_copy(cs->effective_xcpus, trialcs->effective_xcpus); - if ((old_prs > 0) && !is_partition_valid(cs)) + if (old_prs && !is_partition_valid(cs)) { reset_partition_data(cs); + /* effective_xcpus may be cleared, update the subtree too */ + force = true; + } spin_unlock_irq(&callback_lock); /* effective_cpus/effective_xcpus will be updated here */ @@ -2672,8 +2675,11 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs, spin_lock_irq(&callback_lock); cpumask_copy(cs->exclusive_cpus, trialcs->exclusive_cpus); cpumask_copy(cs->effective_xcpus, trialcs->effective_xcpus); - if ((old_prs > 0) && !is_partition_valid(cs)) + if (old_prs && !is_partition_valid(cs)) { reset_partition_data(cs); + /* effective_xcpus may be cleared, update the subtree too */ + force = true; + } spin_unlock_irq(&callback_lock); /* diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh index bdca6c471f87..32e1e44fa0b1 100755 --- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh @@ -434,6 +434,12 @@ TEST_MATRIX=( # cpuset.cpus is allowed, but those extra CPUs are ignored. " C2-3:P1 C3:P1 . . . C2-4 . . 0 A1:|A2:2-3 A1:P1|A2:P1" + # Clearing cpuset.cpus.exclusive of an invalid partition releases its + # exclusive CPUs, including those of its descendants, so a sibling + # can claim them. + " CX2-3:P1 . . C3 T:O2=0:O3=0:X . . X3 0 XA1:|XB1:3 A1:P-1" + " CX2-3:P1 X3 . C3 T:O2=0:O3=0:X . . X3 0 XA1:|XA2:|XB1:3 A1:P-1" + # A child cannot recover until its exclusive CPUs are available again. " CX1-4:P1 CX3-4:P1 . . X1-2 . . . 0 A1:1-2|A2:1-2|XA2: A1:P1|A2:P-1" " CX1-4:P1 CX3-4:P1 . . X1-2:X1-4 . . . 0 A1:1-2|A2:3-4|XA2:3-4 A1:P1|A2:P1" -- 2.34.1