From: Andrew Morton <akpm@linux-foundation.org>
To: Sebastian Capella <sebastian.capella@linaro.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
"Pavel Machek" <pavel@ucw.cz>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linaro-kernel@lists.linaro.org, patches@linaro.org,
"Serge Hallyn" <serge.hallyn@canonical.com>,
"Stephen Warren" <swarren@nvidia.com>,
"Jens Axboe" <axboe@kernel.dk>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Al Viro" <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v3 1/2] init/do_mounts.c: ignore final \n in name_to_dev_t
Date: Wed, 29 Jan 2014 10:41:06 -0800 [thread overview]
Message-ID: <20140129104106.793524a07e48324a32dc6f06@linux-foundation.org> (raw)
In-Reply-To: <20140129182956.14275.72264@capellas-linux>
On Wed, 29 Jan 2014 10:29:56 -0800 Sebastian Capella <sebastian.capella@linaro.org> wrote:
> Hi Andrew,
>
> By the way, I do see a call (sysfs_streq) in use for this purpose
> other places. Sorry, I didn't find it while looking at the original
> problem. I'm not sure if this is preferable, but it appears to have
> been added specifically for the strings coming through sysfs.
Yes, I wrote it ;)
I didn't think sysfs_streq() is well suited to this problem. And the
issue of possibly-null-terminated-strings coming in from userspace is a
common one, so it is desirable that we build up the suite of utilities
to handle this.
There are probably quite a lot of open-coded \n trimming loops which
can be cleaned up using such tools.
grep -r "if .* == '\\\n'" .
> My preference is copying the string and cleaning it up before passing
> it to internal functions, even though we incur an allocation.
Yes. Here on the kernel/userspace boundary we are typically running in
GFP_KERNEL context and the code is not performance critical - it is a
good fit.
WARNING: multiple messages have this Message-ID (diff)
From: akpm@linux-foundation.org (Andrew Morton)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/2] init/do_mounts.c: ignore final \n in name_to_dev_t
Date: Wed, 29 Jan 2014 10:41:06 -0800 [thread overview]
Message-ID: <20140129104106.793524a07e48324a32dc6f06@linux-foundation.org> (raw)
In-Reply-To: <20140129182956.14275.72264@capellas-linux>
On Wed, 29 Jan 2014 10:29:56 -0800 Sebastian Capella <sebastian.capella@linaro.org> wrote:
> Hi Andrew,
>
> By the way, I do see a call (sysfs_streq) in use for this purpose
> other places. Sorry, I didn't find it while looking at the original
> problem. I'm not sure if this is preferable, but it appears to have
> been added specifically for the strings coming through sysfs.
Yes, I wrote it ;)
I didn't think sysfs_streq() is well suited to this problem. And the
issue of possibly-null-terminated-strings coming in from userspace is a
common one, so it is desirable that we build up the suite of utilities
to handle this.
There are probably quite a lot of open-coded \n trimming loops which
can be cleaned up using such tools.
grep -r "if .* == '\\\n'" .
> My preference is copying the string and cleaning it up before passing
> it to internal functions, even though we incur an allocation.
Yes. Here on the kernel/userspace boundary we are typically running in
GFP_KERNEL context and the code is not performance critical - it is a
good fit.
next prev parent reply other threads:[~2014-01-29 18:41 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-03 21:10 [PATCH v3 0/2] PM / Hibernate: sysfs resume Sebastian Capella
2013-10-03 21:10 ` Sebastian Capella
2013-10-03 21:10 ` [PATCH v3 1/2] init/do_mounts.c: ignore final \n in name_to_dev_t Sebastian Capella
2013-10-03 21:10 ` Sebastian Capella
2013-10-03 21:15 ` Andrew Morton
2013-10-03 21:15 ` Andrew Morton
2013-10-03 21:42 ` Sebastian Capella
2013-10-03 21:42 ` Sebastian Capella
2013-10-03 23:47 ` Sebastian Capella
2013-10-03 23:47 ` Sebastian Capella
2013-10-10 17:50 ` Sebastian Capella
2013-10-10 17:50 ` Sebastian Capella
2013-10-10 22:47 ` Eric W. Biederman
2013-10-10 22:47 ` Eric W. Biederman
2013-10-10 23:39 ` Sebastian Capella
2013-10-10 23:39 ` Sebastian Capella
2013-10-22 17:54 ` Sebastian Capella
2013-10-22 17:54 ` Sebastian Capella
2014-01-28 18:59 ` Sebastian Capella
2014-01-28 18:59 ` Sebastian Capella
2014-01-28 20:54 ` Andrew Morton
2014-01-28 20:54 ` Andrew Morton
2014-01-28 20:58 ` Sebastian Capella
2014-01-28 20:58 ` Sebastian Capella
2014-01-29 18:29 ` Sebastian Capella
2014-01-29 18:29 ` Sebastian Capella
2014-01-29 18:41 ` Andrew Morton [this message]
2014-01-29 18:41 ` Andrew Morton
2013-10-03 21:10 ` [PATCH v3 2/2] PM / Hibernate: use name_to_dev_t to parse resume Sebastian Capella
2013-10-03 21:10 ` Sebastian Capella
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