diff -up diffutils-3.6/src/cmp.c.cmp-s-empty diffutils-3.6/src/cmp.c --- diffutils-3.6/src/cmp.c.cmp-s-empty 2017-05-18 18:39:59.000000000 +0100 +++ diffutils-3.6/src/cmp.c 2017-05-22 10:53:28.477147864 +0100 @@ -330,12 +330,15 @@ main (int argc, char **argv) /* If only a return code is needed, and if both input descriptors are associated with plain files, + and if both files are larger than 0 bytes (procfs files are always 0), conclude that the files differ if they have different sizes and if more bytes will be compared than are in the smaller file. */ if (comparison_type == type_status && S_ISREG (stat_buf[0].st_mode) - && S_ISREG (stat_buf[1].st_mode)) + && S_ISREG (stat_buf[1].st_mode) + && stat_buf[0].st_size > 0 + && stat_buf[1].st_size > 0) { off_t s0 = stat_buf[0].st_size - file_position (0); off_t s1 = stat_buf[1].st_size - file_position (1);