On Sun, Mar 19, 2017 at 9:38 AM, Ben Hutchings <ben@xxxxxxxxxxxxxxx> wrote: > On Thu, 2017-03-16 at 23:29 +0900, Greg Kroah-Hartman wrote: >> 4.4-stable review patch. If anyone has any objections, please let me know. >> >> ------------------ >> >> From: Dan Williams <dan.j.williams@xxxxxxxxx> >> >> commit 86ef58a4e35e8fa66afb5898cf6dec6a3bb29f67 upstream. >> >> The interleave-set cookie is a sum that sanity checks the composition of >> an interleave set has not changed from when the namespace was initially >> created. The checksum is calculated by sorting the DIMMs by their >> location in the interleave-set. The comparison for the sort must be >> 64-bit wide, not byte-by-byte as performed by memcmp() in the broken >> case. > [...] >> --- a/drivers/acpi/nfit.c >> +++ b/drivers/acpi/nfit.c > [...] >> +static int cmp_map(const void *m0, const void *m1) >> +{ >> + const struct nfit_set_info_map *map0 = m0; >> + const struct nfit_set_info_map *map1 = m1; >> + >> + return map0->region_offset - map1->region_offset; >> +} > [...] > > This is returning an int, thus it's effectively doing a 32-bit > comparison and not the 64-bit comparison you say is needed. > > I think this function needs to do something like: > > return (map0->region_offset < map1->region_offset) ? -1 : > (map0->region_offset == map1->region_offset) ? 0 : 1; Yes, you're right. We could end up with unexpected sign changes. Good catch.