linux-kernel - [PATCH] sched/cpupri: fix cpupri

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: <1397015410.5212.13.camel@marge.simpson.net>
Date:	Wed, 09 Apr 2014 05:50:10 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] sched/cpupri: fix cpupri_find() for high priority tasks

Hi Steven,

Seems c92211d9b7727 introduced a buglet.

--snip--

Bail on task_pri >= MAX_RT_PRIO excludes userspace prio 98 and 99 tasks,
which map to 100 and 101 respectively.

A user reported that given two SCHED_RR tasks, one hog, one light, the light
task may be stacked on top of the hog iff prio >= 98, latency hit follows.

Signed-off-by: Mike Galbraith <umgwanakikbuti@...il.com>
Cc: <stable@...r.kernel.org>
Fixes: c92211d9b7727 sched/cpupri: Remove the vec->lock
---
 kernel/sched/cpupri.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/kernel/sched/cpupri.c
+++ b/kernel/sched/cpupri.c
@@ -70,9 +70,6 @@ int cpupri_find(struct cpupri *cp, struc
 	int idx = 0;
 	int task_pri = convert_prio(p->prio);
 
-	if (task_pri >= MAX_RT_PRIO)
-		return 0;
-
 	for (idx = 0; idx < task_pri; idx++) {
 		struct cpupri_vec *vec  = &cp->pri_to_cpu[idx];
 		int skip = 0;


--
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/