From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 91BDD1D63DF for ; Wed, 27 Aug 2025 00:58:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756256307; cv=none; b=SFt8udV49+WjzVqRm2f3PcT5UB0BtsC9QVflFKq9Rqbnau+gJh1GseddJ/4MEiXqQzGho5SSJ5gcIjN+Ez6ik0nySNiV15j0tGTLUDz9sAyJ6F/UFnPjLGhCX7d+j6lKulO8+cC0PINWZlt5q8UCoDpbTQbDgBqd3fwUqismL64= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756256307; c=relaxed/simple; bh=pJcb+Fht6vB+reX+TqG9R4aKlunq8AvYtB6xYR2vnQw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LfqbQY3DJETfdRofKXQxfpsmYym/kOJ3On2o7t6dr1DYc9xQuPRpqkHgTLGnXmmXeGh8FtaiZ0ULyhdJ41XvSSN/vTcgc6k6DMQEVlAz5HvQdiHFqPliaZZ5aSPq8yVjgNh1B2urKo7pTRIMLMqUioO3DBeM4j1R9QDX2Q8wauc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=GNh3EhjC; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="GNh3EhjC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756256303; 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: in-reply-to:in-reply-to:references:references; bh=W9Vds8El0nHCfAOchscouR6LADiC3NFwfPcPYTHIEQ4=; b=GNh3EhjCbepf2VLHaBfbfEdtJka/gJuoiytdOAhCRt7ytvIK0FX/ie60mWQ5eyzBlYz1dq nPaFcd+OjV8koJ9RhkQTgjMvfk6yN21M5PZz6/sxRb1MSfvcdhtK8YDgoN0VZnVX2D/lyq 7Te0PBN4mDwQ1AtKTfTHiWn0kwvLX+8= Received: from mx-prod-mc-03.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-482-2asWDuvsMGqG5usYVPu2Zg-1; Tue, 26 Aug 2025 20:58:21 -0400 X-MC-Unique: 2asWDuvsMGqG5usYVPu2Zg-1 X-Mimecast-MFC-AGG-ID: 2asWDuvsMGqG5usYVPu2Zg_1756256300 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CCEB919560B2; Wed, 27 Aug 2025 00:58:19 +0000 (UTC) Received: from fedora (unknown [10.72.116.24]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 23BC519560AB; Wed, 27 Aug 2025 00:58:12 +0000 (UTC) Date: Wed, 27 Aug 2025 08:58:07 +0800 From: Ming Lei To: linan666@huaweicloud.com Cc: axboe@kernel.dk, jianchao.w.wang@oracle.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yangerkun@huawei.com, yi.zhang@huawei.com Subject: Re: [PATCH] blk-mq: check kobject state_in_sysfs before deleting in blk_mq_unregister_hctx Message-ID: References: <20250826084854.1030545-1-linan666@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250826084854.1030545-1-linan666@huaweicloud.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On Tue, Aug 26, 2025 at 04:48:54PM +0800, linan666@huaweicloud.com wrote: > From: Li Nan > > In __blk_mq_update_nr_hw_queues() the return value of > blk_mq_sysfs_register_hctxs() is not checked. If sysfs creation for hctx Looks we should check its return value and handle the failure in both the call site and blk_mq_sysfs_register_hctxs(). > fails, later changing the number of hw_queues or removing disk will > trigger the following warning: > > kernfs: can not remove 'nr_tags', no directory > WARNING: CPU: 2 PID: 637 at fs/kernfs/dir.c:1707 kernfs_remove_by_name_ns+0x13f/0x160 > Call Trace: > remove_files.isra.1+0x38/0xb0 > sysfs_remove_group+0x4d/0x100 > sysfs_remove_groups+0x31/0x60 > __kobject_del+0x23/0xf0 > kobject_del+0x17/0x40 > blk_mq_unregister_hctx+0x5d/0x80 > blk_mq_sysfs_unregister_hctxs+0x94/0xd0 > blk_mq_update_nr_hw_queues+0x124/0x760 > nullb_update_nr_hw_queues+0x71/0xf0 [null_blk] > nullb_device_submit_queues_store+0x92/0x120 [null_blk] > > kobjct_del() was called unconditionally even if sysfs creation failed. > Fix it by checkig the kobject creation statusbefore deleting it. > > Fixes: 477e19dedc9d ("blk-mq: adjust debugfs and sysfs register when updating nr_hw_queues") > Signed-off-by: Li Nan > --- > block/blk-mq-sysfs.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c > index 24656980f443..5c399ac562ea 100644 > --- a/block/blk-mq-sysfs.c > +++ b/block/blk-mq-sysfs.c > @@ -150,9 +150,11 @@ static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx) > return; > > hctx_for_each_ctx(hctx, ctx, i) > - kobject_del(&ctx->kobj); > + if (ctx->kobj.state_in_sysfs) > + kobject_del(&ctx->kobj); > > - kobject_del(&hctx->kobj); > + if (hctx->kobj.state_in_sysfs) > + kobject_del(&hctx->kobj); It is bad to use kobject internal state in block layer. Thanks, Ming