From nobody Thu Dec 18 05:17:47 2025 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 A6BF928D8ED; Tue, 26 Aug 2025 08:57:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756198651; cv=none; b=MG82JlhgdBcR04IJWbSqym4/jpRVw49zu+XsQMCD/YH8Qp7V44xYvkTJpxGDBOMT2xvBOzDvC+DJL7XmlP0Buj1HJIyaZuAxnhW2xACV8p+4pIKBh770s+/jvS+83Vhldo0N31s4dDPSKVu/oobdsiGreIpX4iy4sb8Bx22mXTs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756198651; c=relaxed/simple; bh=YdpElEc8FqofAz4HPN+/tPIgeQ7pHmfY9a81hBS71yg=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=jBdHErmec3t2RBhCaa8zNHFS0zjMd4qXxYe0t3sLrm9jW2Zcm6u97jgJIpvXNnModWyUT982FlwZZHiWoZdLckPv8H/QtS+Eakld9pFSJKV1ISmqvPT7tFSH8OFwPemn9r7KrJV4ucCImL/lAltd+8yHGCNwhuOGoGyh6XnJ+cc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4cB1kt2YwkzYQtLT; Tue, 26 Aug 2025 16:57:26 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id DEEA71A19F3; Tue, 26 Aug 2025 16:57:24 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgCn8Izydq1oQapgAQ--.23704S4; Tue, 26 Aug 2025 16:57:24 +0800 (CST) From: linan666@huaweicloud.com To: axboe@kernel.dk, ming.lei@redhat.com, jianchao.w.wang@oracle.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linan666@huaweicloud.com, yukuai3@huawei.com, yangerkun@huawei.com, yi.zhang@huawei.com Subject: [PATCH] blk-mq: check kobject state_in_sysfs before deleting in blk_mq_unregister_hctx Date: Tue, 26 Aug 2025 16:48:54 +0800 Message-Id: <20250826084854.1030545-1-linan666@huaweicloud.com> X-Mailer: git-send-email 2.39.2 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-CM-TRANSID: gCh0CgCn8Izydq1oQapgAQ--.23704S4 X-Coremail-Antispam: 1UD129KBjvJXoW7WryrCFWfCryfZw45Xw1xAFb_yoW8Aw1UpF W3Ga13W3yDtr4jva12van7Wr13KF4kArykA393Xr1Sv3Wjkrn5WrsYyrWUJFy8trZ3CF4x X3WUJ345Gw40g3JanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9G14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1lnxkEFVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xv F2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r 4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I 648v4I1lw4CEc2x0rVAKj4xxMxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMx C20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAF wI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20x vE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v2 0xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxV W8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUbfWrJUUUUU== X-CM-SenderInfo: polqt0awwwqx5xdzvxpfor3voofrz/ Content-Type: text/plain; charset="utf-8" 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 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 updati= ng nr_hw_queues") Signed-off-by: Li Nan Reviewed-by: Yu Kuai --- 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_ct= x *hctx) return; =20 hctx_for_each_ctx(hctx, ctx, i) - kobject_del(&ctx->kobj); + if (ctx->kobj.state_in_sysfs) + kobject_del(&ctx->kobj); =20 - kobject_del(&hctx->kobj); + if (hctx->kobj.state_in_sysfs) + kobject_del(&hctx->kobj); } =20 static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx) --=20 2.39.2