From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: akpm@osdl.org, mingo@elte.hu
Cc: linux-kernel@vger.kernel.org, dipankar@hill9.org, wli@holomorphy.com
Subject: [PATCH] tasklist-RCU fix in attach_pid()
Date: Tue, 8 Nov 2005 19:22:34 -0800 [thread overview]
Message-ID: <20051109032233.GA3060@us.ibm.com> (raw)
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@us.ibm.com>
---
(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;
}
next reply other threads:[~2005-11-09 3:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-09 3:22 Paul E. McKenney [this message]
2005-11-09 8:14 ` William Lee Irwin III
2005-11-09 14:35 ` Ingo Molnar
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