X-Git-Url: http://git.osdn.net/view?a=blobdiff_plain;f=mm%2Ffadvise.c;h=001877e32f0c57b4712e524393152e2115fa2690;hb=fd97ed8c874dc479d868ad33311ad227ff0c98ee;hp=b8a5bc66b0c09b915237ab600cdeceaa81b8d153;hpb=2ca0a9d80c3a2cd3917b768080cce7f59b9bc490;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

diff --git a/mm/fadvise.c b/mm/fadvise.c
index b8a5bc66b0c0..001877e32f0c 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -68,8 +68,12 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
 		goto out;
 	}
 
-	/* Careful about overflows. Len == 0 means "as much as possible" */
-	endbyte = offset + len;
+	/*
+	 * Careful about overflows. Len == 0 means "as much as possible".  Use
+	 * unsigned math because signed overflows are undefined and UBSan
+	 * complains.
+	 */
+	endbyte = (u64)offset + (u64)len;
 	if (!len || endbyte < len)
 		endbyte = -1;
 	else