Add Eric's fix for reparenting w/in thread group

diff --git a/queue-2.6.19/fix-reparenting-to-the-same-thread-group.patch b/queue-2.6.19/fix-reparenting-to-the-same-thread-group.patch
new file mode 100644 (file)
index 0000000..ca396f0
--- /dev/null
+++ b/queue-2.6.19/fix-reparenting-to-the-same-thread-group.patch
@@ -0,0 +1,82 @@
+From b2b2cbc4b2a2f389442549399a993a8306420baf Mon Sep 17 00:00:00 2001
+From: Eric W. Biederman <ebiederm@xmission.com>
+Date: Thu, 21 Dec 2006 21:28:40 -0700
+Subject: [PATCH] Fix reparenting to the same thread group. (take 2)
+
+This patch fixes the case when we reparent to a different thread in the
+same thread group.  This modifies the code so that we do not send
+signals and do not change the signal to send to SIGCHLD unless we have
+change the thread group of our parents.  It also suppresses sending
+pdeath_sig in this cas as well since the result of geppid doesn't
+change.
+
+Thanks to Oleg for spotting my bug of only fixing this for non-ptraced
+tasks.
+
+Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
+Cc: Mike Galbraith <efault@gmx.de>
+Cc: Albert Cahalan <acahalan@gmail.com>
+Cc: Andrew Morton <akpm@osdl.org>
+Cc: Roland McGrath <roland@redhat.com>
+Cc: Ingo Molnar <mingo@elte.hu>
+Cc: Coywolf Qi Hunt <qiyong@fc-cn.com>
+Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
+Signed-off-by: Linus Torvalds <torvalds@osdl.org>
+[chrisw: fold in 241ceee0b442, Oleg's fix to restore user visible behaviour]
+Signed-off-by: Chris Wright <chrisw@sous-sol.org>
+---
+ kernel/exit.c |   29 ++++++++++++++++++-----------
+ 1 file changed, 18 insertions(+), 11 deletions(-)
+
+--- linux-2.6.19.2.orig/kernel/exit.c
++++ linux-2.6.19.2/kernel/exit.c
+@@ -603,10 +603,6 @@ choose_new_parent(struct task_struct *p,
+ static void
+ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
+ {
+-      /* We don't want people slaying init.  */
+-      if (p->exit_signal != -1)
+-              p->exit_signal = SIGCHLD;
+-
+       if (p->pdeath_signal)
+               /* We already hold the tasklist_lock here.  */
+               group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
+@@ -626,13 +622,7 @@ reparent_thread(struct task_struct *p, s
+               p->parent = p->real_parent;
+               add_parent(p);
+ 
+-              /* If we'd notified the old parent about this child's death,
+-               * also notify the new parent.
+-               */
+-              if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
+-                  thread_group_empty(p))
+-                      do_notify_parent(p, p->exit_signal);
+-              else if (p->state == TASK_TRACED) {
++              if (p->state == TASK_TRACED) {
+                       /*
+                        * If it was at a trace stop, turn it into
+                        * a normal stop since it's no longer being
+@@ -642,6 +632,23 @@ reparent_thread(struct task_struct *p, s
+               }
+       }
+ 
++      /* If this is a threaded reparent there is no need to
++       * notify anyone anything has happened.
++       */
++      if (p->real_parent->group_leader == father->group_leader)
++              return;
++
++      /* We don't want people slaying init.  */
++      if (p->exit_signal != -1)
++              p->exit_signal = SIGCHLD;
++
++      /* If we'd notified the old parent about this child's death,
++       * also notify the new parent.
++       */
++      if (!traced && p->exit_state == EXIT_ZOMBIE &&
++          p->exit_signal != -1 && thread_group_empty(p))
++              do_notify_parent(p, p->exit_signal);
++
+       /*
+        * process group orphan check
+        * Case ii: Our child is in a different pgrp

diff --git a/queue-2.6.19/series b/queue-2.6.19/series
index 0f014c2e0b4c8aa61f188d17eb708d035f3ef48a..48aea6a8c2b20b5b403842e55bd80d6d42a154a6 100644 (file)
--- a/queue-2.6.19/series
+++ b/queue-2.6.19/series
@@ -9,3 +9,4 @@ netfilter-tcp-conntrack-fix-ip_ct_tcp_flag_close_init-value.patch
 netfilter-arp_tables-fix-userspace-compilation.patch
 repair-snd-usb-usx2y-over-ohci.patch
 ib-mthca-fix-off-by-one-in-fmr-handling-on-memfree.patch
+fix-reparenting-to-the-same-thread-group.patch