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
*/
start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT;
end_index = (endbyte >> PAGE_SHIFT);
- if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK) {
+ /*
+ * The page at end_index will be inclusively discarded according
+ * by invalidate_mapping_pages(), so subtracting 1 from
+ * end_index means we will skip the last page. But if endbyte
+ * is page aligned or is at the end of file, we should not skip
+ * that page - discarding the last page is safe enough.
+ */
+ if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK &&
+ endbyte != inode->i_size - 1) {
/* First page is tricky as 0 - 1 = -1, but pgoff_t
* is unsigned, so the end_index >= start_index
* check below would be true and we'll discard the whole