From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 05EF4C5DF93 for ; Fri, 21 Aug 2026 14:26:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:content-type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=IU0vv4gN2o5y5prXUpJQRh2FejWBebUitlBF1Qr8ENg=; b=GYv1TeNG7dU+krdZ9vcGiHtpoh f6xDuH4EEG4Fyx+Wgxn+Sylo2WDu/DcQXDG4pyzJA+QLmOKBnm9Ait9cPca6iDJPkIXoeLxo/I12N 4zRfELCKgVYPHXJTjUBkxvmtBRMcoZFA7BxyLs3KIaItVA5jyDiih0XY+wnsx40M2FoHtbyI88S3i apJfrqLnjj2BRHhhp+suNpWgCLtZpfX9Xp6gVzCxd+r0fUJccrFy3CsvmswmS78vmBN2uR/Zvvve8 VvYzwIbKs/EhAcb0cA5y1+9/iEqar5hymmiDdB1IUQMb5nfz9M/iGlSKjIrrq3dpadPZ0QAZyiUcY qYb9BbDA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wxQCR-0000000DXy8-1LxY; Fri, 21 Aug 2026 14:26:27 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wxQCN-0000000DXwA-2YRi for kexec@lists.infradead.org; Fri, 21 Aug 2026 14:26:25 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787322381; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IU0vv4gN2o5y5prXUpJQRh2FejWBebUitlBF1Qr8ENg=; b=NdEQl0L09bm0MI2r0s1/7gO6d1RbA5jUUEFAvnJE+SQpr01Lo4OE1DThJoqM9wPEuwHe6l 8m2MqovigS65YXh3ufsIuS+8WRzDhc3AArZXDeYFfRQxNn8beXY8js2INhHBefBCNV0ygJ cjru0fe0gstSTCFNtAn97Q8Tb77iIQY= Received: from mx-prod-mc-05.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-255-E0vuZrlmMeSZFl2-63xpJw-1; Fri, 21 Aug 2026 10:24:55 -0400 X-MC-Unique: E0vuZrlmMeSZFl2-63xpJw-1 X-Mimecast-MFC-AGG-ID: E0vuZrlmMeSZFl2-63xpJw_1787322293 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 22CFF1954208; Fri, 21 Aug 2026 14:24:53 +0000 (UTC) Received: from djeffery-thinkpadp1gen3.redhat.corp (headnet05.pony-001.prod.iad2.dc.redhat.com [10.2.32.117]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 9C2E6180034F; Fri, 21 Aug 2026 14:24:50 +0000 (UTC) From: David Jeffery To: driver-core@lists.linux.dev, Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, Tarun Sahu , Stuart Hayes , Laurence Oberman , Bjorn Helgaas , kexec@lists.infradead.org, David Jeffery Subject: [PATCH 3/9] driver core: warn should device_move try to move a need_parent_lock device Date: Fri, 21 Aug 2026 10:24:08 -0400 Message-ID: <20260821142414.150892-4-djeffery@redhat.com> In-Reply-To: <20260821142414.150892-1-djeffery@redhat.com> References: <20260821142414.150892-1-djeffery@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: H9tb4kh-mlCZsmcs1dPWwdxl0dfbSaqZZiyaqTgZt68_1787322293 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260821_072623_744860_0DA226D0 X-CRM114-Status: GOOD ( 12.83 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org Currently, no device has need_parent_lock set and is moved by device_move. need_parent_lock is only set by the usb bus and very few device types ever use device_move. Add a warning to device_move to catch should it ever be used on a device with need_parent_lock set. The combination would break the immutable relationship needed between parent and child for need_parent_lock when locking and unlocking both. Signed-off-by: David Jeffery Tested-by: Laurence Oberman --- drivers/base/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index bd9c2921e326..75f5931165a8 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4712,6 +4712,14 @@ int device_move(struct device *dev, struct device *new_parent, if (!dev) return -EINVAL; + /* + * device_move() should not be used on devices with need_parent_lock + * set. Concurrent reparenting will violate the immutable + * relationship needed while locking and unlocking both parent and + * child. + */ + WARN_ON(dev->bus && dev->bus->need_parent_lock); + device_pm_lock(); new_parent = get_device(new_parent); new_parent_kobj = get_device_parent(dev, new_parent); -- 2.55.0