From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fra-out-012.esa.eu-central-1.outbound.mail-perimeter.amazon.com (fra-out-012.esa.eu-central-1.outbound.mail-perimeter.amazon.com [52.57.120.243]) (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 6CA1830F938 for ; Fri, 7 Nov 2025 08:13:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.57.120.243 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762503218; cv=none; b=iNJ4PRSE+NSmfktc2PPI93sWgKAXCgjIRyTNbFkqk3QEBXniuFeKC6hjR705B4NFFPB2aGYK3PntwosDiA/YXEBJwMh4z6bxQod2QSuIWLJFUMBMt9/YGuBUSVd+gFnDiZuqYTPKZ5AWhW2Zd7xQpbRpi7CTI+eEXXCopDQi+nY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762503218; c=relaxed/simple; bh=4drWl5oVKFuHl+xuGskNxzBylciVz8x2T3SKUA2S0FE=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=INlWIWavQkXobVltUFjDN0C9/kE4dLMH421aNVDJ2V/GsMKrBCgTYJLtG6Dyv7GSbOrYE299w1teUYqBLkanYgYkkf+O0GumNXwOD19ztu0Rfjj8ByG3mmM5eRTRuBvBqOKYADhZEC/BrPrSaQ6oM6KhJSKZn5kAZBwqldhsfGs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=WCrHPElf; arc=none smtp.client-ip=52.57.120.243 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="WCrHPElf" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1762503216; x=1794039216; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=6t2bOWhqRFGRHDboXfRasxJuQqR5SKfxvlginqnwOjY=; b=WCrHPElfccFih/Fum/tCuo4mnsP7MZLfkZqVOVeUhYK27ak1oep6vXtT dEOqcVo9LN1yF37CazmH3RV9bsa/cBcwLjCBFvyByZ5Mf1/DEsq3KSE6x 690xDhRiyUxCMex/7r83ZQGjswriAkNllukow15uVYUjsE3u3pM2zUJ+D h9Vu3LjTInCC2X1pWYQpHDei66pOA4u5Bd2mPiSqA/hYNWgxDetJE6B6R X9ODfcennc4NkRK+xsdBsGHpsd1RakxS70AJfCJBmdYLfpvjiaXGIsqQ7 yBYdX/loRDYZ5LQ6iGHP/4aZC2etZ4tnluFngv8jIz3PxY9obUskaPQLt w==; X-CSE-ConnectionGUID: f6dI5ghBR+asn7PzWqp2kg== X-CSE-MsgGUID: jh4Yrn5OT0SwgNQA4jDeYA== X-IronPort-AV: E=Sophos;i="6.19,286,1754956800"; d="scan'208";a="4714418" Received: from ip-10-6-6-97.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.6.97]) by internal-fra-out-012.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Nov 2025 08:13:18 +0000 Received: from EX19MTAEUA002.ant.amazon.com [54.240.197.232:11665] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.18.231:2525] with esmtp (Farcaster) id a18729ee-b55f-4e0f-9a07-b1edd40c21df; Fri, 7 Nov 2025 08:13:18 +0000 (UTC) X-Farcaster-Flow-ID: a18729ee-b55f-4e0f-9a07-b1edd40c21df Received: from EX19D003EUB001.ant.amazon.com (10.252.51.97) by EX19MTAEUA002.ant.amazon.com (10.252.50.126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.29; Fri, 7 Nov 2025 08:13:17 +0000 Received: from u5934974a1cdd59.ant.amazon.com (10.146.13.223) by EX19D003EUB001.ant.amazon.com (10.252.51.97) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.29; Fri, 7 Nov 2025 08:13:10 +0000 From: Fernand Sieber To: kernel test robot , , , , , , , , , CC: , , , , Subject: Re: [PATCH] sched: Proxy yields to donor tasks Date: Fri, 7 Nov 2025 10:12:53 +0200 Message-ID: <20251107081254.110947-1-sieberf@amazon.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <202511071431.9PLsHNo5-lkp@intel.com> References: <20251106104022.195157-1-sieberf@amazon.com> <202511071431.9PLsHNo5-lkp@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D031UWC001.ant.amazon.com (10.13.139.241) To EX19D003EUB001.ant.amazon.com (10.252.51.97) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Nov 07, 2025 at 02:31:16PM +0800, kernel test robot wrote: > sparse warnings: (new ones prefixed by >>) > >>> kernel/sched/rt.c:529:55: sparse: warning: incorrect type in initializer (different address spaces) >>> kernel/sched/rt.c:976:39: sparse: warning: incorrect type in initializer (different address spaces) Thank you for the report. The warnings occur because my patch changes scheduler yield functions from accessing rq->curr to rq->donor, both of which have identical __rcu annotations. These are pre-existing annotation issues in the scheduler code, which has been directly accessing RCU-annotated pointers without proper dereferencing, relying on runqueue lock protection instead. If we do want to address these sparse warnings, I can make modifications like: - curr = rq->donor; + curr = rcu_dereference_protected(rq->donor, lockdep_is_held(&rq->__lock)); This would have zero runtime overhead while satisfying sparse's RCU checking. Peter, let me know if these warnings should be addressed. Thanks, Fernand Amazon Development Centre (South Africa) (Proprietary) Limited 29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa Registration Number: 2004 / 034463 / 07