[PATCH] tasklist-RCU fix in attach_pid()
From: Paul E. McKenney
Date: Tue Nov 08 2005 - 22:22:17 EST
Hello!
Bug in attach_pid() can result in RCU readers in find_pid() getting
confused if they race with process creation.
Signed-off-by: <paulmck@xxxxxxxxxx>
---
(applies to both 2.6.14-mm1 and -rt)
pid.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -uprNa -X dontdiff linux-2.6.14-mm1/kernel/pid.c linux-2.6.14-mm1-fix-1/kernel/pid.c
--- linux-2.6.14-mm1/kernel/pid.c 2005-11-08 08:18:55.000000000 -0800
+++ linux-2.6.14-mm1-fix-1/kernel/pid.c 2005-11-08 19:02:35.000000000 -0800
@@ -150,6 +150,7 @@ int fastcall attach_pid(task_t *task, en
task_pid = &task->pids[type];
pid = find_pid(type, nr);
+ task_pid->nr = nr;
if (pid == NULL) {
INIT_LIST_HEAD(&task_pid->pid_list);
hlist_add_head_rcu(&task_pid->pid_chain,
@@ -158,7 +159,6 @@ int fastcall attach_pid(task_t *task, en
INIT_HLIST_NODE(&task_pid->pid_chain);
list_add_tail_rcu(&task_pid->pid_list, &pid->pid_list);
}
- task_pid->nr = nr;
return 0;
}
-
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