From 3bfae933dbdebb085216440d1eea406dadfa3d64 Mon Sep 17 00:00:00 2001 From: Dave McCracken Date: Fri, 17 May 2002 21:36:41 -0700 Subject: [PATCH] Thread group exit problem reappeared A long time ago there was thread group code that at exit time tried to reparent a task to another task in the thread group. I discovered a major race condition in this code, and submitted a patch that removed it. This patch was accepted in, I think, 2.4.12. The code reappeared in 2.4.18 and sometime in the 2.5 tree before 2.5.15, breaking applications that use thread groups. As part of chasing this down, I figured out a way to remove the race condition while still preserving this behavior. I've attached a patch against 2.5.15 that fixes it. --- kernel/exit.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index e0c0e7405eff..be0df7d2276c 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -231,7 +231,7 @@ void daemonize(void) /* * When we die, we re-parent all our children. - * Try to give them to another thread in our process + * Try to give them to another thread in our thread * group, and if no such member exists, give it to * the global child reaper process (ie "init") */ @@ -241,8 +241,14 @@ static inline void forget_original_parent(struct task_struct * father) read_lock(&tasklist_lock); - /* Next in our thread group */ - reaper = next_thread(father); + /* Next in our thread group, if they're not already exiting */ + reaper = father; + do { + reaper = next_thread(reaper); + if (!(reaper->flags & PF_EXITING)) + break; + } while (reaper != father); + if (reaper == father) reaper = child_reaper; -- cgit v1.2.3