linux/tools
John Hubbard 64801d19eb mm/gup_benchmark: fix MAP_HUGETLB case
The MAP_HUGETLB ("-H" option) of gup_benchmark fails:

  $ sudo ./gup_benchmark -H
  mmap: Invalid argument

This is because gup_benchmark.c is passing in a file descriptor to
mmap(), but the fd came from opening up the /dev/zero file.  This
confuses the mmap syscall implementation, which thinks that, if the
caller did not specify MAP_ANONYMOUS, then the file must be a huge page
file.  So it attempts to verify that the file really is a huge page
file, as you can see here:

ksys_mmap_pgoff()
{
    if (!(flags & MAP_ANONYMOUS)) {
        retval = -EINVAL;
        if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
            goto out_fput; /* THIS IS WHERE WE END UP */

    else if (flags & MAP_HUGETLB) {
        ...proceed normally, /dev/zero is ok here...

...and of course is_file_hugepages() returns "false" for the /dev/zero
file.

The problem is that the user space program, gup_benchmark.c, really just
wants anonymous memory here.  The simplest way to get that is to pass
MAP_ANONYMOUS whenever MAP_HUGETLB is specified, so that's what this
patch does.

Link: http://lkml.kernel.org/r/20191021212435.398153-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Keith Busch <keith.busch@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:28:58 -08:00
..
accounting
arch tools headers kvm: Sync kvm headers with the kernel sources 2019-10-15 12:30:08 -03:00
bpf tools: bpf: Use !building_out_of_srctree to determine srctree 2019-09-30 10:53:34 +02:00
build tools build: Add capability-related feature detection 2019-08-12 17:14:14 -03:00
cgroup iocost_monitor: Report debt 2019-09-10 12:31:39 -06:00
debugging
firewire
firmware Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
gpio Bulk GPIO changes for the v5.3 kernel cycle: 2019-07-09 09:07:00 -07:00
hv - First round of vmbus hibernation support from Dexuan Cui. 2019-09-24 12:36:31 -07:00
iio tools: iio: add .gitignore 2019-08-18 20:45:57 +01:00
include tools headers UAPI: Sync sched.h with the kernel 2019-10-15 12:44:00 -03:00
io_uring
kvm/kvm_stat
laptop
leds leds: core: Add support for composing LED class device names 2019-07-25 20:07:52 +02:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-19 17:09:11 -04:00
memory-model tools/memory-model: Update the informal documentation 2019-08-09 10:28:57 -07:00
nfsd
objtool KVM: x86: Check kvm_rebooting in kvm_spurious_fault() 2019-09-25 15:23:33 +02:00
pci pci-v5.3-changes 2019-07-15 20:44:49 -07:00
pcmcia
perf perf kmem: Fix memory leak in compact_gfp_flags() 2019-10-16 10:08:32 -03:00
power platform-drivers-x86 for v5.4-2 2019-09-24 12:39:40 -07:00
scripts perf build: Do not use -Wshadow on gcc < 4.8 2019-07-23 09:04:54 -03:00
spi
testing mm/gup_benchmark: fix MAP_HUGETLB case 2019-11-06 08:28:58 -08:00
thermal/tmon
time
usb usbip: tools: Fix read_usb_vudc_device() error path handling 2019-10-28 17:51:06 +01:00
virtio tools/virtio: xen stub 2019-10-13 09:38:27 -04:00
vm tools/vm/slabinfo: add sorting info to help menu 2019-07-12 11:05:46 -07:00
wmi
Makefile tools: Keep list of tools in alphabetical order 2019-08-14 10:59:59 -03:00