From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (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 3B3A122318 for ; Mon, 14 Oct 2024 06:25:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728887157; cv=none; b=p84eF1ohZJrIm6KhzPMMAk9Y69FD11w2ytbFNT2aPp/wIVs6rbzQx8fPBJVtVFIPZHIbvA1bHkleXE0HbEFRc/I34rghwmFfwqgclXcMSXdA96XMovDyFdm1ZjJx2oA3VqNgHMFUqun8fE1kwQZrMmTmTdbw1zhl2CzoIWo0baI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728887157; c=relaxed/simple; bh=+koo6QFKHCOd2RdK0fcAsnUb3mglWLegbw1X29P8XrY=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=SwaswMDd7fBL53JZcD2LQkQS/yIQTmfCx7GdeXKzShYhD/a8Dpt440gFgwombxfQIQ3enEoGW+2XYp/rh15HR4hbGc9uxPF7a+iuaP6Rdkg4z4M6NMv9kRVv5TMsJ9fUYbmf+AdujU/ECOLqvcBuXT9P/13V8IiPQeZfrAIw7T0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=sZcqnzl7; arc=none smtp.client-ip=91.218.175.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="sZcqnzl7" Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1728887153; 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=2alqM5wMLrvrHUM45E9EVij6kVf1hx5mqn5x6ULr8Vo=; b=sZcqnzl7JiISCJ5+wBJaMA00C70UmiXVqminBAjxWzUh4MbS3t8pN/2gF+tqiQBgrvFMgT LMjCeA8MsWCR8kL+fTSuHaRTgpe5Eay+3EddrF46qf/4AA+cnAd6IZHMV1yJ6RTpVzXuke uVba9mWolMweaf6bwZVREGFz3Xi+krU= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3818.100.11.1.3\)) Subject: Re: [PATCH v2] mm: shrinker: avoid memleak in alloc_shrinker_info X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <20241014032336.482088-1-chenridong@huaweicloud.com> Date: Mon, 14 Oct 2024 14:25:04 +0800 Cc: akpm@linux-foundation.org, david@fromorbit.com, zhengqi.arch@bytedance.com, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, chenridong@huawei.com, wangweiyang2@huawei.com Content-Transfer-Encoding: quoted-printable Message-Id: References: <20241014032336.482088-1-chenridong@huaweicloud.com> To: Chen Ridong X-Migadu-Flow: FLOW_OUT > On Oct 14, 2024, at 11:23, Chen Ridong = wrote: >=20 > From: Chen Ridong >=20 > A memleak was found as bellow: >=20 > unreferenced object 0xffff8881010d2a80 (size 32): > comm "mkdir", pid 1559, jiffies 4294932666 > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 @............... > backtrace (crc 2e7ef6fa): > [] __kmalloc_node_noprof+0x394/0x470 > [] alloc_shrinker_info+0x7b/0x1a0 > [] mem_cgroup_css_online+0x11a/0x3b0 > [] online_css+0x29/0xa0 > [] cgroup_apply_control_enable+0x20d/0x360 > [] cgroup_mkdir+0x168/0x5f0 > [] kernfs_iop_mkdir+0x5e/0x90 > [] vfs_mkdir+0x144/0x220 > [] do_mkdirat+0x87/0x130 > [] __x64_sys_mkdir+0x49/0x70 > [] do_syscall_64+0x68/0x140 > [] entry_SYSCALL_64_after_hwframe+0x76/0x7e >=20 > In the alloc_shrinker_info function, when shrinker_unit_alloc return > err, the info won't be freed. Just fix it. >=20 > Fixes: 307bececcd12 ("mm: shrinker: add a secondary array for = shrinker_info::{map, nr_deferred}") > Signed-off-by: Chen Ridong > --- > mm/shrinker.c | 1 + > 1 file changed, 1 insertion(+) >=20 > diff --git a/mm/shrinker.c b/mm/shrinker.c > index dc5d2a6fcfc4..92270413190d 100644 > --- a/mm/shrinker.c > +++ b/mm/shrinker.c > @@ -97,6 +97,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) >=20 > err: > mutex_unlock(&shrinker_mutex); > + kvfree(info); Please transpose kvfree() to the place above mutex_unlock(). We should release the resources in the order which is inverse to the that of acquiring resources. Thanks. > free_shrinker_info(memcg); > return -ENOMEM; > } > --=20 > 2.34.1 >=20