Merge 4.14-rc4 into staging-next

We want the staging/iio fixes in here as well to handle merge issues.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 99736e026712..dee0f75c3013 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -40,6 +40,7 @@
 #include <linux/ratelimit.h>
 #include <linux/kthread.h>
 #include <linux/init.h>
+#include <linux/mmu_notifier.h>
 
 #include <asm/tlb.h>
 #include "internal.h"
@@ -495,6 +496,21 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
         }
 
         /*
+         * If the mm has notifiers then we would need to invalidate them around
+         * unmap_page_range and that is risky because notifiers can sleep and
+         * what they do is basically undeterministic.  So let's have a short
+         * sleep to give the oom victim some more time.
+         * TODO: we really want to get rid of this ugly hack and make sure that
+         * notifiers cannot block for unbounded amount of time and add
+         * mmu_notifier_invalidate_range_{start,end} around unmap_page_range
+         */
+        if (mm_has_notifiers(mm)) {
+                up_read(&mm->mmap_sem);
+                schedule_timeout_idle(HZ);
+                goto unlock_oom;
+        }
+
+        /*
          * MMF_OOM_SKIP is set by exit_mmap when the OOM reaper can't
          * work on the mm anymore. The check for MMF_OOM_SKIP must run
          * under mmap_sem for reading because it serializes against the