From cda1e453414bc017729c65dfc8f5a61e86676c4e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 5 Jun 2002 19:25:39 -0700 Subject: [PATCH] Futex II: Copy-from-user can fail. This patch handles the case where copy_from_user fails (it could have been unmapped from this address space by another thread). --- kernel/futex.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index ed03e2b73787..029c902869f4 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -150,13 +150,14 @@ static int futex_wait(struct list_head *head, set_current_state(TASK_INTERRUPTIBLE); queue_me(head, &q, page, offset); - /* Page is pinned, can't fail */ - if (get_user(curval, uaddr) != 0) - BUG(); + /* Page is pinned, but may no longer be in this address space. */ + if (get_user(curval, uaddr) != 0) { + ret = -EFAULT; + goto out; + } if (curval != val) { ret = -EWOULDBLOCK; - set_current_state(TASK_RUNNING); goto out; } time = schedule_timeout(time); @@ -169,6 +170,7 @@ static int futex_wait(struct list_head *head, goto out; } out: + set_current_state(TASK_RUNNING); /* Were we woken up anyway? */ if (!unqueue_me(&q)) return 0; -- cgit v1.2.3