[PATCH] coredump: kill ptrace related stuff
With this patch zap_process() sets SIGNAL_GROUP_EXIT while sending SIGKILL to
the thread group. This means that a TASK_TRACED task
1. Will be awakened by signal_wake_up(1)
2. Can't sleep again via ptrace_notify()
3. Can't go to do_signal_stop() after return
from ptrace_stop() in get_signal_to_deliver()
So we can remove all ptrace related stuff from coredump path.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/exec.c b/fs/exec.c
index a5c5164..b58ba7d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1368,12 +1368,14 @@
*out_ptr = 0;
}
-static void zap_process(struct task_struct *start, int *ptraced)
+static void zap_process(struct task_struct *start)
{
struct task_struct *t;
unsigned long flags;
spin_lock_irqsave(&start->sighand->siglock, flags);
+ start->signal->flags = SIGNAL_GROUP_EXIT;
+ start->signal->group_stop_count = 0;
t = start;
do {
@@ -1381,22 +1383,17 @@
t->mm->core_waiters++;
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
-
- if (unlikely(t->ptrace) &&
- unlikely(t->parent->mm == t->mm))
- *ptraced = 1;
}
} while ((t = next_thread(t)) != start);
spin_unlock_irqrestore(&start->sighand->siglock, flags);
}
-static void zap_threads (struct mm_struct *mm)
+static void zap_threads(struct mm_struct *mm)
{
struct task_struct *g, *p;
struct task_struct *tsk = current;
struct completion *vfork_done = tsk->vfork_done;
- int traced = 0;
/*
* Make sure nobody is waiting for us to release the VM,
@@ -1413,29 +1410,12 @@
do {
if (p->mm) {
if (p->mm == mm)
- zap_process(p, &traced);
+ zap_process(p);
break;
}
} while ((p = next_thread(p)) != g);
}
read_unlock(&tasklist_lock);
-
- if (unlikely(traced)) {
- /*
- * We are zapping a thread and the thread it ptraces.
- * If the tracee went into a ptrace stop for exit tracing,
- * we could deadlock since the tracer is waiting for this
- * coredump to finish. Detach them so they can both die.
- */
- write_lock_irq(&tasklist_lock);
- do_each_thread(g,p) {
- if (mm == p->mm && p != tsk &&
- p->ptrace && p->parent->mm == mm) {
- __ptrace_detach(p, 0);
- }
- } while_each_thread(g,p);
- write_unlock_irq(&tasklist_lock);
- }
}
static void coredump_wait(struct mm_struct *mm)