linux-kernel - Re: [PATCH] devtmpfs: Calling delete

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 9 Dec 2013 17:06:21 +0800
From:	Axel Lin <axel.lin@...ics.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Rob Landley <rob@...dley.net>, Al Viro <viro@...iv.linux.org.uk>,
	Kay Sievers <kay.sievers@...y.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] devtmpfs: Calling delete_path() only when necessary

2013/12/9 Greg Kroah-Hartman <gregkh@...uxfoundation.org>:
> On Mon, Dec 09, 2013 at 04:54:29PM +0800, Axel Lin wrote:
>> 2013/12/9 Greg Kroah-Hartman <gregkh@...uxfoundation.org>:
>> > On Wed, Dec 04, 2013 at 02:44:14PM +0800, Axel Lin wrote:
>> >> 2013/12/4 Rob Landley <rob@...dley.net>:
>> >> > On 11/16/2013 02:15:23 AM, Axel Lin wrote:
>> >> >>
>> >> >> The deleted variable is always 1 in current code.
>> >> >> Initialize deleted variable to be 0, so delete_path() will be called only
>> >> >> when
>> >> >> necessary.
>> >> >>
>> >> >> Signed-off-by: Axel Lin <axel.lin@...ics.com>
>> >> >
>> >> >
>> >> > I'm not seeing this in linux-next, or a reply on the web archive. Assuming
>> >> > nobody's objected to this, you might want to forward it to
>> >> > trivial@...nel.org.
>> >> >
>> >> > That said, you could describe what it _does_ a little more?
>> >>
>> >> I was expecting Greg to pick up this patch.
>> >>
>> >> I thought the description is pretty clear.
>> >> What the patch does is changing the init value of deleted variable to 0.
>> >> The intention of this change is to avoid unnecessary delete_path() call.
>> >
>> > I agree the logic is a bit odd here, but are you seeing an "unnecessary"
>> > delete_path() call happening?  The code has always been like this from
>> > what I can tell...
>>
>> Honestly, I havn't see the "unnecessary" delete_path() call happening druing my
>> test. I look at the code when I was debugging a hangup issue.
>> (In the end, I think the issue is not related to the devtmpfs code.)
>> But I found the logic for the deleted variable looks odd.
>> There are below possible (unlikely) case:
>> When strchr(nodename, '/') != 0 and
>> 1. If dentry->d_inode is NULL
>> 2. vfs_getattr returns error
>> 3. vfs_unlink returns error except -ENOENT.
>>
>> In these cases, delete_path() will fail anyway.
>>
>> Although this is a unlikely case, and I know the code is there since initial
>> commit. But I think it's still good to fix it.
>
> Have you tested your patch to verify nothing breaks?
Yes. I have this patch in my local build image since the day I sent the patch.
Regards,
Axel
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/