From: Oleg Nesterov sys_times: dont' take tasklist_lock Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton --- kernel/sys.c | 13 +------------ 1 files changed, 1 insertion(+), 12 deletions(-) diff -puN kernel/sys.c~sys_times-dont-take-tasklist_lock kernel/sys.c --- devel/kernel/sys.c~sys_times-dont-take-tasklist_lock 2006-03-11 02:47:04.000000000 -0800 +++ devel-akpm/kernel/sys.c 2006-03-11 02:47:04.000000000 -0800 @@ -1001,7 +1001,7 @@ asmlinkage long sys_times(struct tms __u struct task_struct *t; cputime_t utime, stime, cutime, cstime; - read_lock(&tasklist_lock); + spin_lock_irq(&tsk->sighand->siglock); utime = tsk->signal->utime; stime = tsk->signal->stime; t = tsk; @@ -1011,20 +1011,9 @@ asmlinkage long sys_times(struct tms __u t = next_thread(t); } while (t != tsk); - /* - * While we have tasklist_lock read-locked, no dying thread - * can be updating current->signal->[us]time. Instead, - * we got their counts included in the live thread loop. - * However, another thread can come in right now and - * do a wait call that updates current->signal->c[us]time. - * To make sure we always see that pair updated atomically, - * we take the siglock around fetching them. - */ - spin_lock_irq(&tsk->sighand->siglock); cutime = tsk->signal->cutime; cstime = tsk->signal->cstime; spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); tmp.tms_utime = cputime_to_clock_t(utime); tmp.tms_stime = cputime_to_clock_t(stime); _