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-rw-r--r--kernel/futex.c26
1 files changed, 12 insertions, 14 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 99f8acc..b4f87ba 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1565,12 +1565,11 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
uaddr_faulted:
/*
- * We have to r/w *(int __user *)uaddr, but we can't modify it
- * non-atomically. Therefore, if get_user below is not
- * enough, we need to handle the fault ourselves, while
- * still holding the mmap_sem.
- *
- * ... and hb->lock. :-) --ANK
+ * We have to r/w *(int __user *)uaddr, and we have to modify it
+ * atomically. Therefore, if we continue to fault after get_user()
+ * below, we need to handle the fault ourselves, while still holding
+ * the mmap_sem. This can occur if the uaddr is under contention as
+ * we have to drop the mmap_sem in order to call get_user().
*/
queue_unlock(&q, hb);
@@ -1582,7 +1581,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
}
ret = get_user(uval, uaddr);
- if (!ret && (uval != -EFAULT))
+ if (!ret)
goto retry;
if (to)
@@ -1676,12 +1675,11 @@ out:
pi_faulted:
/*
- * We have to r/w *(int __user *)uaddr, but we can't modify it
- * non-atomically. Therefore, if get_user below is not
- * enough, we need to handle the fault ourselves, while
- * still holding the mmap_sem.
- *
- * ... and hb->lock. --ANK
+ * We have to r/w *(int __user *)uaddr, and we have to modify it
+ * atomically. Therefore, if we continue to fault after get_user()
+ * below, we need to handle the fault ourselves, while still holding
+ * the mmap_sem. This can occur if the uaddr is under contention as
+ * we have to drop the mmap_sem in order to call get_user().
*/
spin_unlock(&hb->lock);
@@ -1694,7 +1692,7 @@ pi_faulted:
}
ret = get_user(uval, uaddr);
- if (!ret && (uval != -EFAULT))
+ if (!ret)
goto retry;
return ret;
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