iomap: Fix possible overflow condition in iomap_write_delalloc_scan

folio_next_index() returns an unsigned long value which left shifted by PAGE_SHIFT could possibly cause an overflow on 32-bit system. Instead use folio_pos(folio) + folio_size(folio), which does this correctly. Suggested-by: Matthew Wilcox <[email protected]> Signed-off-by: Ritesh Harjani (IBM) <[email protected]> Reviewed-by: Darrick J. Wong <[email protected]>
niw · Jul 25, 2023 · eee2d2e · eee2d2e
1 parent cc86181
commit eee2d2e
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
@@ -934,7 +934,7 @@ static int iomap_write_delalloc_scan(struct inode *inode,
 			 * the end of this data range, not the end of the folio.
 			 */
 			*punch_start_byte = min_t(loff_t, end_byte,
-					folio_next_index(folio) << PAGE_SHIFT);
+					folio_pos(folio) + folio_size(folio));
 		}
 
 		/* move offset to start of next folio in range */