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authorOleg Nesterov <oleg@tv-sign.ru>2008-01-15 00:02:37 +0300
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-01-14 13:23:00 -0800
commita98fdcef941e107eeabae622d85a1f476f25a160 (patch)
tree1702a6e810016eea5e995eb7c91a101688e8c59c
parent4fd3670eb1d3c33e8952cf1e79edbb2d517dcfb5 (diff)
fix the "remove task_ppid_nr_ns" commit
Commit 84427eaef1fb91704c7112bdb598c810003b99f3 (remove task_ppid_nr_ns) moved the task_tgid_nr_ns(task->real_parent) outside of lock_task_sighand(). This is wrong, ->real_parent could be freed/reused. Both ->parent/real_parent point to nothing after __exit_signal() because we remove the child from ->children list, and thus the child can't be reparented when its parent exits. rcu_read_lock() protects ->parent/real_parent, but _only_ if we know it was valid before we take rcu lock. Revert this part of the patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/array.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 810eb8fd650..eb97f2897e2 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -426,7 +426,6 @@ static int do_task_stat(struct task_struct *task, char *buffer, int whole)
cgtime = gtime = cputime_zero;
rcu_read_lock();
- ppid = task_tgid_nr_ns(task->real_parent, ns);
if (lock_task_sighand(task, &flags)) {
struct signal_struct *sig = task->signal;
@@ -465,6 +464,7 @@ static int do_task_stat(struct task_struct *task, char *buffer, int whole)
}
sid = task_session_nr_ns(task, ns);
+ ppid = task_tgid_nr_ns(task->real_parent, ns);
pgid = task_pgrp_nr_ns(task, ns);
unlock_task_sighand(task, &flags);