get_user_pages(): fix possible page leak on oom

get_user_pages() must not return the error when i != 0.  When pages !=
NULL we have i get_page()'ed pages.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 350e646032f52ddaefa5c5ee44efa2376261f382..2302d228fe04f3926f8c52bf65965623f1caff05 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1151,7 +1151,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                         * be processed until returning to user space.
                         */
                        if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
-                               return -ENOMEM;
+                               return i ? i : -ENOMEM;
 
                        if (write)
                                foll_flags |= FOLL_WRITE;