From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Americo Wang <xiyou.wangcong@gmail.com>,
Balbir Singh <balbir@in.ibm.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Roland McGrath <roland@redhat.com>,
Spencer Candland <spencer@bluehost.com>,
Stanislaw Gruszka <sgruszka@redhat.com>
Cc: linux-kernel@vger.kernel.org
Subject: [RFC,PATCH 1/2] cputimers/proc: do_task_stat()->task_times() can race with getrusage()
Date: Wed, 24 Mar 2010 21:45:50 +0100 [thread overview]
Message-ID: <20100324204550.GA31777@redhat.com> (raw)
do_task_stat()->task_times() can race with getrusage(), they both can
try to update task->prev_Xtime at the same time.
Remove this bit of d180c5bc "sched: Introduce task_times() to replace
task_{u,s}time()".
See also the next patch.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
fs/proc/array.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- 34-rc1/fs/proc/array.c~PROC_4_DTS_TASK_TIMES_IS_RACY 2010-03-24 19:53:23.000000000 +0100
+++ 34-rc1/fs/proc/array.c 2010-03-24 19:57:37.000000000 +0100
@@ -449,7 +449,8 @@ static int do_task_stat(struct seq_file
if (!whole) {
min_flt = task->min_flt;
maj_flt = task->maj_flt;
- task_times(task, &utime, &stime);
+ utime = task->utime;
+ stime = task->stime;
gtime = task->gtime;
}
next reply other threads:[~2010-03-24 20:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-24 20:45 Oleg Nesterov [this message]
2010-03-26 3:53 ` [RFC,PATCH 1/2] cputimers/proc: do_task_stat()->task_times() can race with getrusage() Balbir Singh
2010-03-26 7:37 ` Stanislaw Gruszka
2010-03-26 16:12 ` Stanislaw Gruszka
2010-03-26 21:49 ` Oleg Nesterov
2010-03-29 11:17 ` Stanislaw Gruszka
2010-03-29 12:54 ` Oleg Nesterov
2010-03-29 18:12 ` [PATCH -mm 0/4] cputimers/proc: do_task_stat: don't walk through the thread list under ->siglock Oleg Nesterov
2010-03-29 18:12 ` [PATCH -mm 1/4] cputimers: thread_group_cputime: cleanup rcu/signal stuff Oleg Nesterov
2010-03-29 18:13 ` [PATCH -mm 2/4] cputimers: make sure thread_group_cputime() can't count the same thread twice lockless Oleg Nesterov
2010-03-30 11:01 ` Stanislaw Gruszka
2010-03-30 13:43 ` Oleg Nesterov
2010-03-29 18:13 ` [PATCH -mm 3/4] cputimers: thread_group_times: make it rcu-safe Oleg Nesterov
2010-03-29 18:14 ` [PATCH -mm 1/4] cputimers: do_task_stat: avoid ->siglock for while_each_thread() Oleg Nesterov
2010-03-29 18:16 ` Oleg Nesterov
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