[PATCH] revert "Drop tasklist lock in do_sched_setscheduler"
sched_setscheduler() looks at ->signal->rlim[]. It is unsafe do
dereference ->signal unless tasklist_lock or ->siglock is held (or p ==
current). We pin the task structure, but this can't prevent from
release_task()->__exit_signal() which sets ->signal = NULL.
Restore tasklist_lock across the setscheduler call.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/sched.c b/kernel/sched.c
index a2be2d0..a234fbe 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4162,10 +4162,8 @@
read_unlock_irq(&tasklist_lock);
return -ESRCH;
}
- get_task_struct(p);
- read_unlock_irq(&tasklist_lock);
retval = sched_setscheduler(p, policy, &lparam);
- put_task_struct(p);
+ read_unlock_irq(&tasklist_lock);
return retval;
}
