Merge tag 'v4.19.59-rt24' into toradex_4.19.y-rttoradex_4.19.y-rt

Linux 4.19.59-rt24

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 6e578905e4ec..b6758c6fffbf 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -65,6 +65,10 @@ static inline void mmdrop_delayed(struct mm_struct *mm)
  * followed by taking the mmap_sem for writing before modifying the
  * vmas or anything the coredump pretends not to change from under it.
  *
+ * It also has to be called when mmgrab() is used in the context of
+ * the process, but then the mm_count refcount is transferred outside
+ * the context of the process to run down_write() on that pinned mm.
+ *
  * NOTE: find_extend_vma() called from GUP context is the only place
  * that can modify the "mm" (notably the vm_start/end) under mmap_sem
  * for reading and outside the context of the process, so it is also