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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54499C433FE for ; Thu, 24 Nov 2022 13:44:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229749AbiKXNoN (ORCPT ); Thu, 24 Nov 2022 08:44:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229542AbiKXNoL (ORCPT ); Thu, 24 Nov 2022 08:44:11 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8014B9E0AE; Thu, 24 Nov 2022 05:44:10 -0800 (PST) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NHzjH09H8zHw0w; Thu, 24 Nov 2022 21:43:31 +0800 (CST) Received: from [10.174.178.185] (10.174.178.185) by canpemm500010.china.huawei.com (7.192.105.118) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 24 Nov 2022 21:44:08 +0800 Subject: Re: [PATCH] blk-mq: fix possible memleak when register 'hctx' failed To: , , References: <20221117022940.873959-1-yebin@huaweicloud.com> CC: From: "yebin (H)" Message-ID: <637F7527.8060307@huawei.com> Date: Thu, 24 Nov 2022 21:44:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <20221117022940.873959-1-yebin@huaweicloud.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.185] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500010.china.huawei.com (7.192.105.118) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ping... On 2022/11/17 10:29, Ye Bin wrote: > From: Ye Bin > > There's issue as follows when do fault injection test: > unreferenced object 0xffff888132a9f400 (size 512): > comm "insmod", pid 308021, jiffies 4324277909 (age 509.733s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 08 f4 a9 32 81 88 ff ff ...........2.... > 08 f4 a9 32 81 88 ff ff 00 00 00 00 00 00 00 00 ...2............ > backtrace: > [<00000000e8952bb4>] kmalloc_node_trace+0x22/0xa0 > [<00000000f9980e0f>] blk_mq_alloc_and_init_hctx+0x3f1/0x7e0 > [<000000002e719efa>] blk_mq_realloc_hw_ctxs+0x1e6/0x230 > [<000000004f1fda40>] blk_mq_init_allocated_queue+0x27e/0x910 > [<00000000287123ec>] __blk_mq_alloc_disk+0x67/0xf0 > [<00000000a2a34657>] 0xffffffffa2ad310f > [<00000000b173f718>] 0xffffffffa2af824a > [<0000000095a1dabb>] do_one_initcall+0x87/0x2a0 > [<00000000f32fdf93>] do_init_module+0xdf/0x320 > [<00000000cbe8541e>] load_module+0x3006/0x3390 > [<0000000069ed1bdb>] __do_sys_finit_module+0x113/0x1b0 > [<00000000a1a29ae8>] do_syscall_64+0x35/0x80 > [<000000009cd878b0>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > Fault injection context as follows: > kobject_add > blk_mq_register_hctx > blk_mq_sysfs_register > blk_register_queue > device_add_disk > null_add_dev.part.0 [null_blk] > > As 'blk_mq_register_hctx' may already add some objects when failed halfway, > but there isn't do fallback, caller don't know which objects add failed. > To solve above issue just do fallback when add objects failed halfway in > 'blk_mq_register_hctx'. > > Signed-off-by: Ye Bin > --- > block/blk-mq-sysfs.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c > index 93997d297d42..4515288fbe35 100644 > --- a/block/blk-mq-sysfs.c > +++ b/block/blk-mq-sysfs.c > @@ -185,7 +185,7 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx) > { > struct request_queue *q = hctx->queue; > struct blk_mq_ctx *ctx; > - int i, ret; > + int i, j, ret; > > if (!hctx->nr_ctx) > return 0; > @@ -197,9 +197,16 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx) > hctx_for_each_ctx(hctx, ctx, i) { > ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu); > if (ret) > - break; > + goto out; > } > > + return 0; > +out: > + hctx_for_each_ctx(hctx, ctx, j) { > + if (j < i) > + kobject_del(&ctx->kobj); > + } > + kobject_del(&hctx->kobj); > return ret; > } >