Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261380AbVCHEfK (ORCPT ); Mon, 7 Mar 2005 23:35:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261403AbVCHEfK (ORCPT ); Mon, 7 Mar 2005 23:35:10 -0500 Received: from waste.org ([216.27.176.166]:47770 "EHLO waste.org") by vger.kernel.org with ESMTP id S261380AbVCHEe2 (ORCPT ); Mon, 7 Mar 2005 23:34:28 -0500 Date: Mon, 7 Mar 2005 20:33:49 -0800 From: Matt Mackall To: Andrew Morton Cc: Paul Davis , joq@io.com, cfriesen@nortelnetworks.com, chrisw@osdl.org, hch@infradead.org, rlrevell@joe-job.com, arjanv@redhat.com, mingo@elte.hu, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [request for inclusion] Realtime LSM Message-ID: <20050308043349.GG3120@waste.org> References: <20050112185258.GG2940@waste.org> <200501122116.j0CLGK3K022477@localhost.localdomain> <20050307195020.510a1ceb.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050307195020.510a1ceb.akpm@osdl.org> User-Agent: Mutt/1.5.6+20040907i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4786 Lines: 138 On Mon, Mar 07, 2005 at 07:50:20PM -0800, Andrew Morton wrote: > > So I still have the rt-lsm patch floating about, saying "merge me, merge > me!". I'm not sure that the world would end were I to do so. > > Consider this a prod in the direction of those who were pushing > alternatives ;) I think Chris Wright's last rlimit patch is more sensible and ready to go. And I think I may have even convinced Ingo on this point before the conversation died last time around. So here's that patch again, updated to 2.6.11. Compiles cleanly. Chris, please add a signed-off-by. Add a pair of rlimits for allowing non-root tasks to raise nice and rt priorities. Defaults to traditional behavior. Originally written by Chris Wright. Signed-off-by: Matt Mackall Index: rlimits/include/linux/sched.h =================================================================== --- rlimits.orig/include/linux/sched.h 2005-03-03 22:50:14.000000000 -0800 +++ rlimits/include/linux/sched.h 2005-03-07 20:18:30.000000000 -0800 @@ -791,6 +791,7 @@ extern void sched_idle_next(void); extern void set_user_nice(task_t *p, long nice); extern int task_prio(const task_t *p); extern int task_nice(const task_t *p); +extern int can_nice(const task_t *p, const int nice); extern int task_curr(const task_t *p); extern int idle_cpu(int cpu); extern int sched_setscheduler(struct task_struct *, int, struct sched_param *); Index: rlimits/kernel/sched.c =================================================================== --- rlimits.orig/kernel/sched.c 2005-03-02 22:51:08.000000000 -0800 +++ rlimits/kernel/sched.c 2005-03-07 20:23:17.000000000 -0800 @@ -3273,6 +3273,19 @@ out_unlock: EXPORT_SYMBOL(set_user_nice); +/* + * can_nice - check if a task can reduce its nice value + * @p: task + * @nice: nice value + */ +int can_nice(const task_t *p, const int nice) +{ + /* convert nice value [19,-20] to rlimit style value [0,39] */ + int nice_rlim = 19 - nice; + return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || + capable(CAP_SYS_NICE)); +} + #ifdef __ARCH_WANT_SYS_NICE /* @@ -3292,12 +3305,8 @@ asmlinkage long sys_nice(int increment) * We don't have to worry. Conceptually one call occurs first * and we have a single winner. */ - if (increment < 0) { - if (!capable(CAP_SYS_NICE)) - return -EPERM; - if (increment < -40) - increment = -40; - } + if (increment < -40) + increment = -40; if (increment > 40) increment = 40; @@ -3307,6 +3316,9 @@ asmlinkage long sys_nice(int increment) if (nice > 19) nice = 19; + if (increment < 0 && !can_nice(current, nice)) + return -EPERM; + retval = security_task_setnice(current, nice); if (retval) return retval; @@ -3422,6 +3434,7 @@ recheck: return -EINVAL; if ((policy == SCHED_FIFO || policy == SCHED_RR) && + param->sched_priority > p->signal->rlim[RLIMIT_RTPRIO].rlim_cur && !capable(CAP_SYS_NICE)) return -EPERM; if ((current->euid != p->euid) && (current->euid != p->uid) && Index: rlimits/kernel/sys.c =================================================================== --- rlimits.orig/kernel/sys.c 2005-03-02 22:51:07.000000000 -0800 +++ rlimits/kernel/sys.c 2005-03-07 20:18:30.000000000 -0800 @@ -225,7 +225,7 @@ static int set_one_prio(struct task_stru error = -EPERM; goto out; } - if (niceval < task_nice(p) && !capable(CAP_SYS_NICE)) { + if (niceval < task_nice(p) && !can_nice(p, niceval)) { error = -EACCES; goto out; } Index: rlimits/include/asm-generic/resource.h =================================================================== --- rlimits.orig/include/asm-generic/resource.h 2005-03-02 18:30:27.000000000 -0800 +++ rlimits/include/asm-generic/resource.h 2005-03-07 20:21:04.000000000 -0800 @@ -20,8 +20,10 @@ #define RLIMIT_LOCKS 10 /* maximum file locks held */ #define RLIMIT_SIGPENDING 11 /* max number of pending signals */ #define RLIMIT_MSGQUEUE 12 /* maximum bytes in POSIX mqueues */ - -#define RLIM_NLIMITS 13 +#define RLIMIT_NICE 13 /* max nice prio allowed to raise to + 0-39 for nice level 19 .. -20 */ +#define RLIMIT_RTPRIO 14 /* maximum realtime priority */ +#define RLIM_NLIMITS 15 #endif /* @@ -53,6 +55,8 @@ [RLIMIT_LOCKS] = { RLIM_INFINITY, RLIM_INFINITY }, \ [RLIMIT_SIGPENDING] = { MAX_SIGPENDING, MAX_SIGPENDING }, \ [RLIMIT_MSGQUEUE] = { MQ_BYTES_MAX, MQ_BYTES_MAX }, \ + [RLIMIT_NICE] = { 0, 0 }, \ + [RLIMIT_RTPRIO] = { 0, 0 }, \ } #endif /* __KERNEL__ */ -- Mathematics is the supreme nostalgia of our time. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/