From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.109 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794213129; b=VH6nLX10fCPngxHYFoVrHtNAWqu73gOPUmEuLLmAqk7ktP3q9poB0wghuhqDEwnSdjqq zS/j51yZ+0ywxSb1Wb/RH1WwFzjUv0mNEQn9qdU5bNmD0PQGbtTyUvhoDD4gPvQttlcSN /35/fWIx3fVkKeUums4FAg315kvD5gpvHhHv1ih6xXdj9b+tsID2atAwJ2zU8mxWEhuuS 84jdqBGonI0kIq7Q0yLZatmid6/Ukrwj8L2uZOwCp5uvm3ZoT3wPh+U1Lb10tZJESR5QW S7mY12MlImEr/Q5h5MRtoYwbmSomHT9CrikBmO3TPnWGNA5xuMDnHmfJVRPVZhRNeLQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794213129; 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:MIME-Version:Content-Transfer-Encoding; bh=KmjDL+ZYjMuGRzVCbJ/ua2rZFiezU/zJqi55Q1TXzTU=; b=yXJInrPXuQzoEdE2VvJCniBfrWC/qnHARBILL14qSZNhfCp0bcjoQO3qFuWYkuyj4HJj SI+6B1137wtDayavVPZJKyRQ+ULeiM71Jn70S7l468cItNz5AGSO308tQ3bNcbPK2IpOW 00CEPm5qcTQCeM6seAb14BrH18j68/7p3LJw1KsOJK7oMi0wElXgiOwU52v9qZGSgruUl KxnzN9xd2QI7x9jyNKzjZZJLNwFQvRFxJoKpf3t8hBrWOpwfFyx3n96Eoq0aDFWXIbjbd JE6VN7LCarf5SiezbCKIVdQH6zBeBpQeK3JC/jIWBnClIyqNiyHAUFuT+MzQShhox6A== 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=k5K1tyvV; arc=none smtp.remote-ip=95.215.58.109 Received: from mta1.migadu.com (out-109.mta1.migadu.com [95.215.58.109]) (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 B9657606A321 for ; Mon, 9 Nov 2026 08:32:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org B9657606A321 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=k5K1tyvV X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=QRV3SldNox6KvqwDi88YeJ7A25jJBfRYkhmfbFDJhhY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794213124; v=1; x=1794817924; b=k5K1tyvVGvkrqrCzBT33RcQ2SL4vUmQGCmi4dl0KpbDL6X2pcbJSK+Z5z4KYoMl0jD7xRQCz OQE7mWnTeZzemp+z9BWRqej3yvnK6MH2GauCHXMdzUocVvvHp6w2Hjx6GhEa6iqDyNBY3TfbNdS OqkOVR0UvZz57ZRjecaonMyg= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta12.migadu.com with ESMTPS id 5016b8722ed8e219; Mon, 09 Nov 2026 08:32:04 +0000 X-Mizu-Trace-ID: 5016b8722ed8e219 X-Migadu-Flow: FLOW_OUT From: Fushuai Wang To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, sshegde@linux.ibm.com Cc: linux-kernel@vger.kernel.org, wangfushuai@baidu.com Subject: [PATCH] sched/core: Fix a TOCTOU bug in sched_non_preferred_cpu_push_stop() Date: Mon, 9 Nov 2026 16:31:30 +0800 Message-Id: <20261109083130.1679-1-fushuai.wang@linux.dev> X-Mailer: git-send-email 2.39.2 (Apple Git-143) 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: Fushuai Wang sched_push_current_non_preferred_cpu() is called in irq context. It checks is_migration_disabled() before queuing the stopper, but the task may continue running and enter migrate_disable() before the stopper runs. Recheck is_migration_disabled() in sched_non_preferred_cpu_push_stop() before calling __migrate_task(). WARNING: kernel/sched/core.c:3432 at set_task_cpu+0x1b8/0xdf0, CPU#21: migration/21/152 Stopper: sched_non_preferred_cpu_push_stop+0x0/0xb10 <- sched_push_current_non_preferred_cpu+0x6a6/0x9a0 ... Call Trace: ? __this_cpu_preempt_check+0x13/0x20 move_queued_task+0xfc/0x650 ? is_cpu_allowed+0x341/0x820 ? __this_cpu_preempt_check+0x13/0x20 sched_non_preferred_cpu_push_stop+0x7b7/0xb10 ? __pfx_sched_non_preferred_cpu_push_stop+0x10/0x10 ... Fixes: 74699f56ebcf ("sched/core: Push current task from non preferred CPU") Signed-off-by: Fushuai Wang --- kernel/sched/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1a088d4576f5..8ed7613eafd6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -11317,7 +11317,8 @@ static int sched_non_preferred_cpu_push_stop(void *arg) rq->npc_push_work_pending = false; update_rq_clock(rq); - if (task_rq(p) == rq && task_on_rq_queued(p)) { + if (task_rq(p) == rq && task_on_rq_queued(p) && + !is_migration_disabled(p)) { struct rq *dest_rq = __migrate_task(rq, &rf, p, cpu); if (rq != dest_rq) -- 2.36.1