From 9cb65bc3b1114004e2ccee5939031325c7bf16e8 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Mika=20Penttil=C3=A4?= <mika.penttila@nextfour.com>
Date: Tue, 15 Mar 2016 14:56:45 -0700
Subject: [PATCH] mm/memory.c: make apply_to_page_range() more robust
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Arm and arm64 used to trigger this BUG_ON() - this has now been fixed.

But a WARN_ON() here is sufficient to catch future buggy callers.

Signed-off-by: Mika Penttilä <mika.penttila@nextfour.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/memory.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index 8132787ae4d5..8adb5b756264 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1876,7 +1876,9 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
 	unsigned long end = addr + size;
 	int err;
 
-	BUG_ON(addr >= end);
+	if (WARN_ON(addr >= end))
+		return -EINVAL;
+
 	pgd = pgd_offset(mm, addr);
 	do {
 		next = pgd_addr_end(addr, end);
-- 
2.20.1