linux-kernel - Re: [PATCH] ipc/msg: add msgsnd_timed and msgrcv

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-next>] [day] [month] [year] [list]

Message-Id: <20210303171220.79faee7108f846b8e140e44d@linux-foundation.org>
Date:   Wed, 3 Mar 2021 17:12:20 -0800
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     Eric Gao <eric.tech@...mail.com>
Cc:     jbi.octave@...il.com, linux-kernel@...r.kernel.org,
        Manfred Spraul <manfred@...orfullife.com>,
        Davidlohr Bueso <dave@...olabs.net>
Subject: Re: [PATCH] ipc/msg: add msgsnd_timed and msgrcv_timed syscall for
 system V message queue

On Tue, 23 Feb 2021 23:11:43 +0800 Eric Gao <eric.tech@...mail.com> wrote:

> sometimes, we need the msgsnd or msgrcv syscall can return after a limited
> time, so that the business thread do not be blocked here all the time. In
> this case, I add the msgsnd_timed and msgrcv_timed syscall that with time
> parameter, which has a unit of ms.

Please cc Manfred and Davidlohr on ipc/ changes.

The above is a very brief description for a new syscall!  Please go to
great lengths to tell us why this is considered useful - what are the
use cases?

Also, please fully describe the proposed syscall interface right here
in the changelog.  Please be prepared to later prepare a full manpage.

> ...
> +SYSCALL_DEFINE5(msgsnd_timed, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
> +		int, msgflg, long, timeoutms)

Specifying the timeout in milliseconds is problematic - it's very
coarse.  See sys_epoll_pwait2()'s use of timespecs.