[RESEND][PATCH 05/15] tty: audit: Take siglock directly

From: Peter Hurley
Date: Sun Jan 10 2016 - 00:03:04 EST


lock_task_sighand() is for situations where the struct task_struct*
may disappear while trying to deref the sighand; this never applies
to 'current'.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/tty_audit.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
index 9effa81..5f65653 100644
--- a/drivers/tty/tty_audit.c
+++ b/drivers/tty/tty_audit.c
@@ -180,22 +180,19 @@ void tty_audit_tiocsti(struct tty_struct *tty, char ch)
int tty_audit_push_current(void)
{
struct tty_audit_buf *buf = ERR_PTR(-EPERM);
- struct task_struct *tsk = current;
unsigned long flags;

- if (!lock_task_sighand(tsk, &flags))
- return -ESRCH;
-
- if (tsk->signal->audit_tty) {
- buf = tsk->signal->tty_audit_buf;
+ spin_lock_irqsave(&current->sighand->siglock, flags);
+ if (current->signal->audit_tty) {
+ buf = current->signal->tty_audit_buf;
if (buf)
atomic_inc(&buf->count);
}
- unlock_task_sighand(tsk, &flags);
+ spin_unlock_irqrestore(&current->sighand->siglock, flags);

/*
* Return 0 when signal->audit_tty set
- * but tsk->signal->tty_audit_buf == NULL.
+ * but current->signal->tty_audit_buf == NULL.
*/
if (!buf || IS_ERR(buf))
return PTR_ERR(buf);
--
2.7.0