From: Oleg Nesterov Date: Wed, 29 Mar 2006 00:11:21 +0000 (-0800) Subject: [PATCH] sys_times: don't take tasklist_lock X-Git-Tag: v2.6.17-rc1~179 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d7185c818925ba5fe90efa75840d0b415032774;p=linux-2.6 [PATCH] sys_times: don't take tasklist_lock sys_times: don't take tasklist_lock Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/sys.c b/kernel/sys.c index 84371fdc66..7ef7f6054c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1206,7 +1206,7 @@ asmlinkage long sys_times(struct tms __user * tbuf) 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; @@ -1216,20 +1216,9 @@ asmlinkage long sys_times(struct tms __user * tbuf) 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);