kill PT_ATTACHED
Since the patch
"Fix ptrace_attach()/ptrace_traceme()/de_thread() race"
commit f5b40e363ad6041a96e3da32281d8faa191597b9
we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock.
This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer"
which were needed to catch the "ptrace attach is in progress" case. We can
also remove the flag itself since nobody else uses it.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/exit.c b/kernel/exit.c
index eb9934a..1f2c152 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1514,18 +1514,7 @@
static inline int my_ptrace_child(struct task_struct *p)
{
- if (!(p->ptrace & PT_PTRACED))
- return 0;
- if (!(p->ptrace & PT_ATTACHED))
- return 1;
- /*
- * This child was PTRACE_ATTACH'd. We should be seeing it only if
- * we are the attacher. If we are the real parent, this is a race
- * inside ptrace_attach. It is waiting for the tasklist_lock,
- * which we have to switch the parent links, but has already set
- * the flags in p->ptrace.
- */
- return (p->parent != p->real_parent);
+ return p->ptrace & PT_PTRACED;
}
static long do_wait(pid_t pid, int options, struct siginfo __user *infop,