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 <[email protected]>
--- rc1/fs/exec.c~3_PTRACE 2006-04-06 15:19:33.000000000 +0400
+++ rc1/fs/exec.c 2006-04-06 19:56:36.000000000 +0400
@@ -1384,12 +1384,14 @@ static void format_corename(char *corena
*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 {
@@ -1397,22 +1399,17 @@ static void zap_process(struct task_stru
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,
@@ -1429,29 +1426,12 @@ static void zap_threads (struct mm_struc
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)
--- rc1/include/linux/ptrace.h~3_PTRACE 2006-03-01 21:57:22.000000000 +0300
+++ rc1/include/linux/ptrace.h 2006-04-06 16:37:54.000000000 +0400
@@ -84,7 +84,6 @@ extern int ptrace_readdata(struct task_s
extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
extern int ptrace_attach(struct task_struct *tsk);
extern int ptrace_detach(struct task_struct *, unsigned int);
-extern void __ptrace_detach(struct task_struct *, unsigned int);
extern void ptrace_disable(struct task_struct *);
extern int ptrace_check_attach(struct task_struct *task, int kill);
extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
--- rc1/kernel/ptrace.c~3_PTRACE 2006-04-03 16:21:26.000000000 +0400
+++ rc1/kernel/ptrace.c 2006-04-06 16:41:41.000000000 +0400
@@ -183,7 +183,7 @@ bad:
return retval;
}
-void __ptrace_detach(struct task_struct *child, unsigned int data)
+static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
{
child->exit_code = data;
/* .. re-parent .. */
@@ -202,8 +202,7 @@ int ptrace_detach(struct task_struct *ch
ptrace_disable(child);
write_lock_irq(&tasklist_lock);
- if (child->ptrace)
- __ptrace_detach(child, data);
+ __ptrace_detach(child, data);
write_unlock_irq(&tasklist_lock);
return 0;
-
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