signals: move cred_guard_mutex from task_struct to signal_struct

Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec
itself and we can reuse ->cred_guard_mutex for it.  Yes, concurrent
execve() has no worth.

Let's move ->cred_guard_mutex from task_struct to signal_struct.  It
naturally prevent multiple-threads-inside-exec.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KOSAKI Motohiro
2010-10-27 15:34:08 -07:00
committed by Linus Torvalds
parent b840115083
commit 9b1bf12d5d
8 changed files with 21 additions and 20 deletions

View File

@@ -181,7 +181,7 @@ int ptrace_attach(struct task_struct *task)
* under ptrace.
*/
retval = -ERESTARTNOINTR;
if (mutex_lock_interruptible(&task->cred_guard_mutex))
if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
goto out;
task_lock(task);
@@ -208,7 +208,7 @@ int ptrace_attach(struct task_struct *task)
unlock_tasklist:
write_unlock_irq(&tasklist_lock);
unlock_creds:
mutex_unlock(&task->cred_guard_mutex);
mutex_unlock(&task->signal->cred_guard_mutex);
out:
return retval;
}