From nobody Sat Oct 4 17:32:56 2025 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (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 DB965222566 for ; Thu, 14 Aug 2025 11:25:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755170717; cv=none; b=W66E26MesKhZVHB7sc5VySYyMMHdNPNDoYW9ZhahyqXPh9zlS1e8GfkuslRf3iRDzkwRuzPilShfLPdbbiWleNkaWFAc7GdbO7eFhfe1pazm61U93qOtfVK5lcjvshsqvEexnJKyi2ggzaJoKzPkJfSz1wEApRDTZCg8mt891f8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755170717; c=relaxed/simple; bh=wp3rwYwUgjRyjVgaK+Ct89o2TRJ1NLg5QDHGpD5DFg4=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=gfDiRbSnUeLXMdKgp/ntB/UyDY8QesFbmwkM0Mo7xJtdm8NEDY6FdCoJfcSbuDRyrSC/7PsKuKR5VZoy5BSqdKSmfbK/c639MAeutzCcGpQS9IV80I8pxBeuzaAql2tGEoajxwhe51j9NTR0jaXG+HvGWHbfpnam50BusTbgHKo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4c2jYm0b7yztTFw; Thu, 14 Aug 2025 19:24:12 +0800 (CST) Received: from dggemv705-chm.china.huawei.com (unknown [10.3.19.32]) by mail.maildlp.com (Postfix) with ESMTPS id 17AD8180B51; Thu, 14 Aug 2025 19:25:12 +0800 (CST) Received: from kwepemq200012.china.huawei.com (7.202.194.183) by dggemv705-chm.china.huawei.com (10.3.19.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 14 Aug 2025 19:25:11 +0800 Received: from huawei.com (10.175.112.208) by kwepemq200012.china.huawei.com (7.202.194.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 14 Aug 2025 19:25:11 +0800 From: Wang Wensheng To: , , , , , , , CC: , Subject: [PATCH 1/3] driver core: Fix concurrent problem of deferred_probe_extend_timeout() Date: Thu, 14 Aug 2025 19:10:21 +0800 Message-ID: <20250814111023.2693-2-wangwensheng4@huawei.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20250814111023.2693-1-wangwensheng4@huawei.com> References: <20250814111023.2693-1-wangwensheng4@huawei.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-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemq200012.china.huawei.com (7.202.194.183) Content-Type: text/plain; charset="utf-8" The deferred_probe_timeout_work may be canceled forever unexpected when deferred_probe_extend_timeout() executes concurrently. Start with deferred_probe_timeout_work pending, and the problem would occur after the following sequence. CPU0 CPU1 deferred_probe_extend_timeout -> cancel_delayed_work =3D> true deferred_probe_extend_timeout -> cancel_delayed_wrok -> __cancel_work -> try_grab_pending -> schedule_delayed_work -> queue_delayed_work_on since pending bit is grabbed, just return without doing anything -> set_work_pool_and_clear_pending this __cancel_work return false and the work would never be queued again The root cause is that the PENDING_BIT of the work_struct would be set temporaily in __cancel_work and this bit could prevent the work_struct to be queued in another CPU. Use deferred_probe_mutex to protect the cancel and queue operations for the deferred_probe_timeout_work to fix this problem. Fixes: 2b28a1a84a0e ("driver core: Extend deferred probe timeout on driver = registration") Signed-off-by: Wang Wensheng --- drivers/base/dd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 13ab98e033ea..1983919917e0 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -323,6 +323,7 @@ static DECLARE_DELAYED_WORK(deferred_probe_timeout_work= , deferred_probe_timeout_ =20 void deferred_probe_extend_timeout(void) { + mutex_lock(&deferred_probe_mutex); /* * If the work hasn't been queued yet or if the work expired, don't * start a new one. @@ -333,6 +334,7 @@ void deferred_probe_extend_timeout(void) pr_debug("Extended deferred probe timeout by %d secs\n", driver_deferred_probe_timeout); } + mutex_unlock(&deferred_probe_mutex); } =20 /** --=20 2.22.0