From 57a059187d5ba5592e36c6f23d046bc37616f346 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 10 Dec 2014 15:45:27 -0800 Subject: [PATCH] exit: reparent: cleanup the changing of ->parent 1. Cosmetic, but "if (t->parent == father)" looks a bit confusing. We need to change t->parent if and only if t is not traced. 2. If we actually want this BUG_ON() to ensure that parent/ptrace match each other, then we should also take ptrace_reparented() case into account too. 3. Change this code to use for_each_thread() instead of deprecated while_each_thread(). [dan.carpenter@oracle.com: silence a bogus static checker warning] Signed-off-by: Oleg Nesterov Cc: Aaron Tomlin Cc: Alexey Dobriyan Cc: "Eric W. Biederman" , Cc: Sterling Alexander Cc: Peter Zijlstra Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 0272305bf855..464971e6923e 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -557,7 +557,7 @@ static void reparent_leader(struct task_struct *father, struct task_struct *p, static void forget_original_parent(struct task_struct *father) { - struct task_struct *p, *n, *reaper; + struct task_struct *p, *t, *n, *reaper; LIST_HEAD(dead_children); write_lock_irq(&tasklist_lock); @@ -569,18 +569,15 @@ static void forget_original_parent(struct task_struct *father) reaper = find_new_reaper(father); list_for_each_entry_safe(p, n, &father->children, sibling) { - struct task_struct *t = p; - - do { + for_each_thread(p, t) { t->real_parent = reaper; - if (t->parent == father) { - BUG_ON(t->ptrace); + BUG_ON((!t->ptrace) != (t->parent == father)); + if (likely(!t->ptrace)) t->parent = t->real_parent; - } if (t->pdeath_signal) group_send_sig_info(t->pdeath_signal, SEND_SIG_NOINFO, t); - } while_each_thread(p, t); + } reparent_leader(father, p, &dead_children); } write_unlock_irq(&tasklist_lock);