From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0681C1B86F3 for ; Wed, 10 Jul 2024 10:03:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720605805; cv=none; b=BtAEUQ2pPzjGR4XaWpSjtQ2IYfMVCf52MOa/0MMfhTS8IaQBfsMMTYkOFipuK5dvVx8c1la3s0Iv50YtXNpLdIv3aTDu7RDwjgqGfvCJOkxZ9j8axtXAvsR2YI9Z5QhI7QkneedBjGgu890Eh5oNj/59lApZCgCCTb7f79Kx6Ao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720605805; c=relaxed/simple; bh=nIT+15KolhN25FJludlfUIU4OFZgBNyHRtf2cl2yjVw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SHBHHD9WgN9dJKy+PzpBPJN/mIWKOvPiR5xHqDm8c6zzJhatbKQtalh6nHSBkqHOBqSM8DBgHxqhdVsPoYPeLiPiQrLiwjwH371SHkwIoEO/kQAHJsNGIUR3xPLN9mw6gmi+V6gOvpKzLupKB6pOkAGpxHRaz4noyijXVk/5FCw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4F80B106F; Wed, 10 Jul 2024 03:03:47 -0700 (PDT) Received: from arm.com (e121798.manchester.arm.com [10.32.101.22]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 323B23F762; Wed, 10 Jul 2024 03:03:21 -0700 (PDT) Date: Wed, 10 Jul 2024 11:03:17 +0100 From: Alexandru Elisei To: leixiang Cc: will@kernel.org, julien.thierry.kdev@gmail.com, kvm@vger.kernel.org, xieming@kylinos.cn Subject: Re: [PATCH] kvm tools:Fix memory leakage in open all disks Message-ID: References: <20240618075247.1394144-1-leixiang@kylinos.cn> <1720577870543075.69.seg@mailgw.kylinos.cn> Precedence: bulk X-Mailing-List: kvm@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: Hi, On Wed, Jul 10, 2024 at 06:00:53PM +0800, leixiang wrote: > Dear Alex, > Thanks for your reply. > > On 2024/7/10 16:27, Alexandru Elisei wrote: > > Hi, > > > > On Wed, Jul 10, 2024 at 04:12:37PM +0800, leixiang wrote: > >> Dear Alex, > >> Thank you for your reply and suggestions. > >> > >> On 2024/7/9 18:12, Alexandru Elisei wrote: > >>> Hi, > >>> > >>> Adding the kvmtool maintainers (you can find them in the README file). > >>> > >>> On Tue, Jun 18, 2024 at 03:52:47PM +0800, leixiang wrote: > >>>> Fix memory leakage in disk/core disk_image__open_all when malloc disk failed, > >>>> should free the disks that already malloced. > >>>> > >>>> Signed-off-by: Lei Xiang > >>>> Suggested-by: Xie Ming > >>>> --- > >>>> disk/core.c | 6 ++++-- > >>>> 1 file changed, 4 insertions(+), 2 deletions(-) > >>>> > >>>> diff --git a/disk/core.c b/disk/core.c > >>>> index dd2f258..affeece 100644 > >>>> --- a/disk/core.c > >>>> +++ b/disk/core.c > >>>> @@ -195,8 +195,10 @@ static struct disk_image **disk_image__open_all(struct kvm *kvm) > >>>> > >>>> if (wwpn) { > >>>> disks[i] = malloc(sizeof(struct disk_image)); > >>>> - if (!disks[i]) > >>>> - return ERR_PTR(-ENOMEM); > >>>> + if (!disks[i]) { > >>>> + err = ERR_PTR(-ENOMEM); > >>>> + goto error; > >>>> + } > >>>> disks[i]->wwpn = wwpn; > >>>> disks[i]->tpgt = tpgt; > >>> > >>> Currently, the latest patch on branch master is ca31abf5d9c3 ("arm64: Allow > >>> the user to select the max SVE vector length"), and struct disk_image > >>> doesn't have a tpgt field. Did you write this patch on a local branch? > >>> > >>>> continue; > >>> > >> There is no doubt that you are correct, I had realize that I git clone a wrong repo. > >>> This is what the 'error' label does: > >>> > >>> error: > >>> for (i = 0; i < count; i++) > >>> if (!IS_ERR_OR_NULL(disks[i])) > >>> disk_image__close(disks[i]); > >>> > >>> free(disks); > >>> return err; > >>> > >>> And disk_image__close() ends up poking all sort of fields from struct > >>> disk_image, including dereferencing pointers embedded in the struct. If > >>> WWPN is specified for a disk, struct disk_image is allocated using malloc > >>> as above, the field wwwpn is set and the rest of the fields are left > >>> uninitialized. Because of this, calling disk_image__close() on a struct > >>> disk_image with wwpn can lead to all sorts of nasty things happening. > >>> > >>> May I suggest allocating disks[i] using calloc in the wwpn case to fix > >>> this? Ideally, you would have two patches: > >>> > >>> 1. A patch that changes the disk[i] allocation to calloc(), to prevent > >>> disk_image__close() accessing unitialized fields when disk_image__open() > >>> fails after initialized a WWPN disk. > >>> > >>> 2. This patch. > >>> > > > >> When the new disk_image is allocated successfully, > >> the fields will eventually be initialized by disk_image__new(). > >> And disk_image__close() accessing fields also checked before use. > >> So I don't think it's necessary to replace malloc with calloc. > > > > When and where is disk_image__new() called? > > > Sorry, I was ignored the 'continue' in the code flow. > There is no doubt that your suggestions are forward-looking, > and I have made changes to the patch according to your suggestions. Great, thanks for checking, I was worried that there was something that I missed. Thanks, Alex