From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-184.mta0.migadu.com (out-184.mta0.migadu.com [91.218.175.184]) (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 33BB910940 for ; Sat, 12 Oct 2024 02:43:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728701025; cv=none; b=CmiUHcAASJNy7x4nFJv/Pv1p0XlKvtOaSQXWl7fltknVU3fC8rfGHPgS79TSx4yO069br9KumeH2ck/CqvZE/NJeQ8SPE/sUfsxPqXe24mtbBrwbU4D8v6WJiNtAHdUlWzrw4eP4c6U1k6kp5+sk9WO0Hd0eVCq8Nq5nPIBr8+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728701025; c=relaxed/simple; bh=ETG6es4LYnOKjvPoafCe3E53dgmEX7Vn9LX2MaiyQ40=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=QYgdcKdpCIvSSXXngLaXFD3FEQvmniV2EkPgMD+vRwBEjNytOzLsqMuy2hCXyMuIlWaDADC55+CojlClp+/59A+G7f0oH5lM9bR5aktQ2iFiYUqTS3XPDc+G2JFf+M6R5CvLkfi1W2uzVM0qMXvtGD3ce9EAMga3E+N5Xt4nouE= 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=GSisi06m; arc=none smtp.client-ip=91.218.175.184 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="GSisi06m" Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1728701020; 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=Lmcrt7U3ZF2GZVkRUj69jQ8X2zDyWcY2mYXTszBBFwY=; b=GSisi06m315dLYfNpbTGWOhZdm/bxa8ZTCfBuEMvN6D1G7MltFacsUMj+cO0HczBsia0tS TuVHLZ6W/T47quDACtOuZw2D7/glacw49xjNJatK8IT9zZWME7ZPhxnkk8ymQ+taiDSOJO wX+t2EsiXvXnnbtnX8knf/VB5B1+f8c= 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] 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: <20241011142105.391157-1-chenridong@huaweicloud.com> Date: Sat, 12 Oct 2024 10:42:52 +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: <63593DC0-21DD-40C1-A4D8-6082F2BB4222@linux.dev> References: <20241011142105.391157-1-chenridong@huaweicloud.com> To: Chen Ridong X-Migadu-Flow: FLOW_OUT > On Oct 11, 2024, at 22:21, 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 | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) >=20 > diff --git a/mm/shrinker.c b/mm/shrinker.c > index dc5d2a6fcfc4..e4b795ee6d2e 100644 > --- a/mm/shrinker.c > +++ b/mm/shrinker.c > @@ -87,8 +87,10 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) > if (!info) > goto err; > info->map_nr_max =3D shrinker_nr_max; > - if (shrinker_unit_alloc(info, NULL, nid)) > + if (shrinker_unit_alloc(info, NULL, nid)) { > + kvfree(info); > goto err; Since we already use goto to do the cleanup for failure, I don't like to mix two different ways to do the similar thing. I suggest adding the kvfree (BTW, it could handle NULL argument) to the label of err. Muchun, Thanks. > + } > rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, = info); > } > mutex_unlock(&shrinker_mutex); > --=20 > 2.34.1 >=20