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use __set_task_state() for TRACED/STOPPED tasks

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1. It is much easier to grep for ->state change if __set_task_state() is used
   instead of the direct assignment.

2. ptrace_stop() and handle_group_stop() use set_task_state() which adds the
   unneeded mb() (btw even if we use mb() it is still possible that do_wait()
   sees the new ->state but not ->exit_code, but this is ok).

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2008-02-06 01:36:13 -08:00 committed by Linus Torvalds
parent 06b8e878a9
commit d9ae90ac4b
3 changed files with 6 additions and 8 deletions
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2
kernel/fork.c
View file

@ -1510,7 +1510,7 @@ long do_fork(unsigned long clone_flags,
if (!(clone_flags & CLONE_STOPPED))
wake_up_new_task(p, clone_flags);
else
p->state = TASK_STOPPED;
__set_task_state(p, TASK_STOPPED);
if (unlikely (trace)) {
current->ptrace_message = nr;

10
kernel/ptrace.c
View file

@ -53,7 +53,7 @@ void ptrace_untrace(struct task_struct *child)
spin_lock(&child->sighand->siglock);
if (task_is_traced(child)) {
if (child->signal->flags & SIGNAL_STOP_STOPPED) {
child->state = TASK_STOPPED;
__set_task_state(child, TASK_STOPPED);
} else {
signal_wake_up(child, 1);
}
@ -103,18 +103,16 @@ int ptrace_check_attach(struct task_struct *child, int kill)
&& child->signal != NULL) {
ret = 0;
spin_lock_irq(&child->sighand->siglock);
if (task_is_stopped(child)) {
if (task_is_stopped(child))
child->state = TASK_TRACED;
} else if (!task_is_traced(child) && !kill) {
else if (!task_is_traced(child) && !kill)
ret = -ESRCH;
}
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
if (!ret && !kill) {
if (!ret && !kill)
wait_task_inactive(child);
}
/* All systems go.. */
return ret;

2
kernel/signal.c
View file

@ -1601,7 +1601,7 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
current->exit_code = exit_code;
/* Let the debugger run. */
set_current_state(TASK_TRACED);
__set_current_state(TASK_TRACED);
spin_unlock_irq(&current->sighand->siglock);
try_to_freeze();
read_lock(&tasklist_lock);