aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2009-12-09 14:19:31 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2010-10-30 08:45:25 -0400
commit3c80fe4ac9cfb13b1bfa4edf1544e8b656716694 (patch)
treec605435b642323cd76eea9567a43d8c67b9c9db1 /kernel
parentf7a998a9491f2da1d3e44d150aa611d10093da4f (diff)
downloadlinux-2.6.38-lt-ux500-3c80fe4ac9cfb13b1bfa4edf1544e8b656716694.tar.gz
audit: Call tty_audit_push_task() outside preempt disabled
While auditing all tasklist_lock read_lock sites I stumbled over the following call chain: audit_prepare_user_tty() read_lock(&tasklist_lock); tty_audit_push_task(); mutex_lock(&buf->mutex); --> buf->mutex is locked with preemption disabled. Solve this by acquiring a reference to the task struct under rcu_read_lock and call tty_audit_push_task outside of the preempt disabled region. Move all code which needs to be protected by sighand lock into tty_audit_push_task() and use lock/unlock_sighand as we do not hold tasklist_lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/audit.c25
1 files changed, 9 insertions, 16 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index a300931fc45..8429afea37b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -467,23 +467,16 @@ static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid)
struct task_struct *tsk;
int err;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
tsk = find_task_by_vpid(pid);
- err = -ESRCH;
- if (!tsk)
- goto out;
- err = 0;
-
- spin_lock_irq(&tsk->sighand->siglock);
- if (!tsk->signal->audit_tty)
- err = -EPERM;
- spin_unlock_irq(&tsk->sighand->siglock);
- if (err)
- goto out;
-
- tty_audit_push_task(tsk, loginuid, sessionid);
-out:
- read_unlock(&tasklist_lock);
+ if (!tsk) {
+ rcu_read_unlock();
+ return -ESRCH;
+ }
+ get_task_struct(tsk);
+ rcu_read_unlock();
+ err = tty_audit_push_task(tsk, loginuid, sessionid);
+ put_task_struct(tsk);
return err;
}