From nobody Wed Feb 11 13:05:50 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D36B716D9D4 for ; Mon, 22 Jul 2024 13:30:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721655055; cv=none; b=EbOccyDbmBcAUipcnJN3OAFs141VmiyZkjtBzHCA4H4jUsWd+NNik92vsBIpQFbNqZJwQeaN0RIargBOb7qR0yqBngYBEnF6CJ/3GyZJQyjonNN4zH5NgihOmhGxqVEIt68YrSqGJAxLXc4FYXLCWgPe6Qbub8hA7iJQBTTjqOs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721655055; c=relaxed/simple; bh=lIaaePxXmnbJj8vKYVGoFuDWtPcijK3hH3x0jKBHy2c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=F0VWORQdgl90CQ9oV9YCOleDLoWlkkCuet04NcCdnE/SGLSzojsKqqFc0uHgK+cFlYf7nuddizQVkWbs/G29dRmasmgXEGJtesyL9K/81gHsR88D/WtjCW9rsCZ7CHoJcN+0J9qHEWrRtxdI2OyuZBx8J4v76suEzwbjnryi9LM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=BA7KAw6n; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BA7KAw6n" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1721655052; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VBbvFchsdGqDlenHLSJuaCBk6m+5EChCmdEPeRVzw5Y=; b=BA7KAw6n2CIZQDo2bKMMOCN3OvHzq7eh8AEgIEx580PWB6sqpSJubf9ohAycBYNJ/FCjsh BAleGl99Knt20QKM5XOfhbBjkmBdoOw8wPm8MKWScZS4zzsy+Cl+zaX3vfReVRz4duiQbb AGMnCMvwLU60mz1kU9B13/m3gZepwlo= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-323-GJjFNYZ3N7W_nIqL4zMZtA-1; Mon, 22 Jul 2024 09:30:48 -0400 X-MC-Unique: GJjFNYZ3N7W_nIqL4zMZtA-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C3CF41944A89; Mon, 22 Jul 2024 13:30:30 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.96.134.70]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 531171955D53; Mon, 22 Jul 2024 13:30:13 +0000 (UTC) From: Wander Lairson Costa To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org (open list:SCHEDULER) Cc: Wander Lairson Costa Subject: [PATCH 1/3] sched/deadline: Fix warning in migrate_enable for boosted tasks Date: Mon, 22 Jul 2024 10:29:25 -0300 Message-ID: <20240722132935.14426-2-wander@redhat.com> In-Reply-To: <20240722132935.14426-1-wander@redhat.com> References: <20240722132935.14426-1-wander@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Content-Type: text/plain; charset="utf-8" When running the following command: while true; do stress-ng --cyclic 30 --timeout 30s --minimize --quiet done a warning is eventually triggered: WARNING: CPU: 43 PID: 2848 at kernel/sched/deadline.c:794 setup_new_dl_entity+0x13e/0x180 ... Call Trace: ? show_trace_log_lvl+0x1c4/0x2df ? enqueue_dl_entity+0x631/0x6e0 ? setup_new_dl_entity+0x13e/0x180 ? __warn+0x7e/0xd0 ? report_bug+0x11a/0x1a0 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 enqueue_dl_entity+0x631/0x6e0 enqueue_task_dl+0x7d/0x120 __do_set_cpus_allowed+0xe3/0x280 __set_cpus_allowed_ptr_locked+0x140/0x1d0 __set_cpus_allowed_ptr+0x54/0xa0 migrate_enable+0x7e/0x150 rt_spin_unlock+0x1c/0x90 group_send_sig_info+0xf7/0x1a0 ? kill_pid_info+0x1f/0x1d0 kill_pid_info+0x78/0x1d0 kill_proc_info+0x5b/0x110 __x64_sys_kill+0x93/0xc0 do_syscall_64+0x5c/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 RIP: 0033:0x7f0dab31f92b This warning occurs because set_cpus_allowed dequeues and enqueues tasks with the ENQUEUE_RESTORE flag set. If the task is boosted, the warning is triggered. A boosted task already had its parameters set by rt_mutex_setprio, and a new call to setup_new_dl_entity is unnecessary, hence the WARN_ON call. Check if we are requeueing a boosted task and avoid calling setup_new_dl_entity if that's the case. Signed-off-by: Wander Lairson Costa Fixes: 2279f540ea7d ("sched/deadline: Fix priority inheritance with multipl= e scheduling classes") --- The initial idea for this fix was to introduce another ENQUEUE flag, ENQUEUE_SET_CPUS_ALLOWED. When this flag was set, the deadline scheduler would bypass the call to setup_new_dl_entity, regardless of whether the task was boosted. However, this idea was abandoned due to the presence of other DEQUEUE_SAVE/ENQUEUE_RESTORE pairs in the code. Ultimately, a simpler approach was chosen, which achieves the same practical effects without the need to create an additional flag for enqueue_task. Signed-off-by: Wander Lairson Costa --- kernel/sched/deadline.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index f59e5c19d944..312e8fa7ce94 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1753,6 +1753,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se, int = flags) } else if (flags & ENQUEUE_REPLENISH) { replenish_dl_entity(dl_se); } else if ((flags & ENQUEUE_RESTORE) && + !is_dl_boosted(dl_se) && dl_time_before(dl_se->deadline, rq_clock(rq_of_dl_se(dl_se)))) { setup_new_dl_entity(dl_se); } --=20 2.45.2