[PATCH] CRED: ptrace_attach() should use the target process's mutex

[David Howells <dhowells@redhat.com>]

ptrace_attach() should use the target process's mutex when attaching to it,
not the current (tracer) process's mutex.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 kernel/ptrace.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)


diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 893a099..2ee343a 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -174,7 +174,7 @@ int ptrace_attach(struct task_struct *task)
 	/* Protect exec's credential calculations against our interference;
 	 * SUID, SGID and LSM creds get determined differently under ptrace.
 	 */
-	retval = mutex_lock_interruptible(&current->cred_exec_mutex);
+	retval = mutex_lock_interruptible(&task->cred_exec_mutex);
 	if (retval  < 0)
 		goto out;
 
@@ -218,7 +218,7 @@ repeat:
 bad:
 	write_unlock_irqrestore(&tasklist_lock, flags);
 	task_unlock(task);
-	mutex_unlock(&current->cred_exec_mutex);
+	mutex_unlock(&task->cred_exec_mutex);
 out:
 	return retval;
 }