[PATCH] fix OOM killing of swapoff

These days, if you swapoff when there isn't enough memory, OOM killer gives
"BUG: scheduling while atomic" and the machine hangs: badness() needs to do
its PF_SWAPOFF return after the task_unlock (tasklist_lock is also held
here, so p isn't going to be freed: PF_SWAPOFF might get turned off at any
moment, but that doesn't really matter).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 6969cfb33901..b278b8d60eee 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -61,12 +61,6 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
         }
 
         /*
-         * swapoff can easily use up all memory, so kill those first.
-         */
-        if (p->flags & PF_SWAPOFF)
-                return ULONG_MAX;
-
-        /*
          * The memory size of the process is the basis for the badness.
          */
         points = mm->total_vm;
@@ -77,6 +71,12 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
         task_unlock(p);
 
         /*
+         * swapoff can easily use up all memory, so kill those first.
+         */
+        if (p->flags & PF_SWAPOFF)
+                return ULONG_MAX;
+
+        /*
          * Processes which fork a lot of child processes are likely
          * a good choice. We add half the vmsize of the children if they
          * have an own mm. This prevents forking servers to flood the