From: subashab@codeaurora.org
To: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Mel Gorman <mgorman@techsingularity.net>,
Al Viro <viro@zeniv.linux.org.uk>,
Johannes Weiner <hannes@cmpxchg.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Daniel Cashman <dcashman@google.com>, Willy Tarreau <w@1wt.eu>,
Arnd Bergmann <arnd@arndb.de>, Hanjun Guo <guohanjun@huawei.com>,
Xishi Qiu <qiuxishi@huawei.com>
Subject: Re: [RFC] kernel/sysctl.c: return -EINVAL when write invalid val to ulong type sysctl
Date: Sat, 26 Nov 2016 16:15:38 -0700 [thread overview]
Message-ID: <6d58a831975bfebea981289c6a1fd4bc@codeaurora.org> (raw)
In-Reply-To: <669ac5a2-8b2f-5a47-305d-f6cf7cff4f63@huawei.com>
On 2016-11-26 02:13, Yisheng Xie wrote:
> I tried to echo an invalid value to an unsigned long type sysctl on
> 4.9.0-rc6:
> linux:~# cat /proc/sys/vm/user_reserve_kbytes
> 131072
> linux:~# echo -1 > /proc/sys/vm/user_reserve_kbytes
> linux:~# cat /proc/sys/vm/user_reserve_kbytes
> 131072
>
> The echo operation got error and the value do not write to
> user_reserve_kbytes,
> however, user do not know it until check the value again.
>
> Is it more suitable to return -EINVAL when echo an invalid value to an
> unsigned long
> type sysctl, in order to let user know what happened without checking
> its value once more?
> Just as what int type sysctl do:
> linux:~#cat /proc/sys/kernel/sysctl_writes_strict
> 1
> linux:~# echo 3 > /proc/sys/kernel/sysctl_writes_strict
> bash: echo: write error: Invalid argument
>
> ----------------------
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 706309f..40e9285 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2485,10 +2485,14 @@ static int __do_proc_doulongvec_minmax(void
> *data, struct ctl_table *table, int
> sizeof(proc_wspace_sep),
> NULL);
> if (err)
> break;
> - if (neg)
> - continue;
> - if ((min && val < *min) || (max && val > *max))
> - continue;
> + if (neg) {
> + err = -EINVAL;
> + break;
> + }
> + if ((min && val < *min) || (max && val > *max))
> {
> + err = -EINVAL;
> + break;
> + }
> *i = val;
> } else {
> val = convdiv * (*i) / convmul;
Agree, this should be similar to proc_douintvec
root@vm:~# echo 8192 > /proc/sys/net/core/xfrm_aevent_rseqth
root@vm:~# cat /proc/sys/net/core/xfrm_aevent_rseqth
8192
root@vm:~# echo -1 > /proc/sys/net/core/xfrm_aevent_rseqth
-bash: echo: write error: Invalid argument
root@vm:~# cat /proc/sys/net/core/xfrm_aevent_rseqth
8192
--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project
next prev parent reply other threads:[~2016-11-26 23:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-26 9:13 [RFC] kernel/sysctl.c: return -EINVAL when write invalid val to ulong type sysctl Yisheng Xie
2016-11-26 23:15 ` subashab [this message]
2016-11-29 10:24 ` Yisheng Xie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6d58a831975bfebea981289c6a1fd4bc@codeaurora.org \
--to=subashab@codeaurora.org \
--cc=acme@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=bristot@redhat.com \
--cc=dcashman@google.com \
--cc=ebiederm@xmission.com \
--cc=guohanjun@huawei.com \
--cc=hannes@cmpxchg.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=qiuxishi@huawei.com \
--cc=viro@zeniv.linux.org.uk \
--cc=w@1wt.eu \
--cc=xieyisheng1@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).