From 269484a492d9177072ee11ec8c9bff71d256837a Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Tue, 30 Mar 2010 11:09:53 +0200 Subject: sched: Fix proc_sched_set_task() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Latencytop clearing sum_exec_runtime via proc_sched_set_task() breaks task_times(). Other places in kernel use nvcsw and nivcsw, which are being cleared as well, Clear task statistics only. Reported-by: Török Edwin Signed-off-by: Mike Galbraith Cc: Hidetoshi Seto Cc: Arjan van de Ven Signed-off-by: Peter Zijlstra LKML-Reference: <1269940193.19286.14.camel@marge.simson.net> Signed-off-by: Ingo Molnar --- kernel/sched_debug.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'kernel/sched_debug.c') diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 67f95aada4b..9b49db14403 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -518,8 +518,4 @@ void proc_sched_set_task(struct task_struct *p) p->se.nr_wakeups_idle = 0; p->sched_info.bkl_count = 0; #endif - p->se.sum_exec_runtime = 0; - p->se.prev_sum_exec_runtime = 0; - p->nvcsw = 0; - p->nivcsw = 0; } -- cgit v1.2.3-70-g09d2 From b629317e66fb1c6066c550dded45ab85a936163c Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 22 Apr 2010 17:30:40 +0800 Subject: sched: Fix an RCU warning in print_task() With CONFIG_PROVE_RCU=y, a warning can be triggered: $ cat /proc/sched_debug ... kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection! ... Both cgroup_path() and task_group() should be called with either rcu_read_lock or cgroup_mutex held. The rcu_dereference_check() does include cgroup_lock_is_held(), so we know that this lock is not held. Therefore, in a CONFIG_PREEMPT kernel, to say nothing of a CONFIG_PREEMPT_RT kernel, the original code could have ended up copying a string out of the freelist. This patch inserts RCU read-side primitives needed to prevent this scenario. Signed-off-by: Li Zefan Signed-off-by: Paul E. McKenney --- kernel/sched_debug.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/sched_debug.c') diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 9b49db14403..19be00ba612 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -114,7 +114,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { char path[64]; + rcu_read_lock(); cgroup_path(task_group(p)->css.cgroup, path, sizeof(path)); + rcu_read_unlock(); SEQ_printf(m, " %s", path); } #endif -- cgit v1.2.3-70-g09d2