linux-stable.git/tools/testing/selftests/vm, branch v5.13.2

selftests/vm/pkeys: refill shadow register after implicit kernel write

2021-07-14T15:07:48+00:00

[ Upstream commit 6039ca254979694c5362dfebadd105e286c397bb ]

The pkey test code keeps a "shadow" of the pkey register around.  This
ensures that any bugs which might write to the register can be caught more
quickly.

Generally, userspace has a good idea when the kernel is going to write to
the register.  For instance, alloc_pkey() is passed a permission mask.
The caller of alloc_pkey() can update the shadow based on the return value
and the mask.

But, the kernel can also modify the pkey register in a more sneaky way.
For mprotect(PROT_EXEC) mappings, the kernel will allocate a pkey and
write the pkey register to create an execute-only mapping.  The kernel
never tells userspace what key it uses for this.

This can cause the test to fail with messages like:

	protection_keys_64.2: pkey-helpers.h:132: _read_pkey_reg: Assertion `pkey_reg == shadow_pkey_reg' failed.

because the shadow was not updated with the new kernel-set value.

Forcibly update the shadow value immediately after an mprotect().

Link: https://lkml.kernel.org/r/20210611164200.EF76AB73@viggo.jf.intel.com
Fixes: 6af17cf89e99 ("x86/pkeys/selftests: Add PROT_EXEC test")
Signed-off-by: Dave Hansen 
Signed-off-by: Thomas Gleixner 
Tested-by: Aneesh Kumar K.V 
Cc: Ram Pai 
Cc: Sandipan Das 
Cc: Florian Weimer 
Cc: "Desnes A. Nunes do Rosario" 
Cc: Ingo Molnar 
Cc: Thiago Jung Bauermann 
Cc: Michael Ellerman 
Cc: Michal Hocko 
Cc: Michal Suchanek 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

selftests/vm/pkeys: handle negative sys_pkey_alloc() return code

2021-07-14T15:07:48+00:00

[ Upstream commit bf68294a2ec39ed7fec6a5b45d52034e6983157a ]

The alloc_pkey() sefltest function wraps the sys_pkey_alloc() system call.
On success, it updates its "shadow" register value because
sys_pkey_alloc() updates the real register.

But, the success check is wrong.  pkey_alloc() considers any non-zero
return code to indicate success where the pkey register will be modified.
This fails to take negative return codes into account.

Consider only a positive return value as a successful call.

Link: https://lkml.kernel.org/r/20210611164157.87AB4246@viggo.jf.intel.com
Fixes: 5f23f6d082a9 ("x86/pkeys: Add self-tests")
Reported-by: Thomas Gleixner 
Signed-off-by: Dave Hansen 
Tested-by: Aneesh Kumar K.V 
Cc: Ram Pai 
Cc: Sandipan Das 
Cc: Florian Weimer 
Cc: "Desnes A. Nunes do Rosario" 
Cc: Ingo Molnar 
Cc: Thiago Jung Bauermann 
Cc: Michael Ellerman 
Cc: Michal Hocko 
Cc: Michal Suchanek 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random

2021-07-14T15:07:48+00:00

[ Upstream commit f36ef407628835a7d7fb3d235b1f1aac7022d9a3 ]

Patch series "selftests/vm/pkeys: Bug fixes and a new test".

There has been a lot of activity on the x86 front around the XSAVE
architecture which is used to context-switch processor state (among other
things).  In addition, AMD has recently joined the protection keys club by
adding processor support for PKU.

The AMD implementation helped uncover a kernel bug around the PKRU "init
state", which actually applied to Intel's implementation but was just
harder to hit.  This series adds a test which is expected to help find
this class of bug both on AMD and Intel.  All the work around pkeys on x86
also uncovered a few bugs in the selftest.

This patch (of 4):

The "random" pkey allocation code currently does the good old:

	srand((unsigned int)time(NULL));

*But*, it unfortunately does this on every random pkey allocation.

There may be thousands of these a second.  time() has a one second
resolution.  So, each time alloc_random_pkey() is called, the PRNG is
*RESET* to time().  This is nasty.  Normally, if you do:

	srand();
	foo = rand();
	bar = rand();

You'll be quite guaranteed that 'foo' and 'bar' are different.  But, if
you do:

	srand(1);
	foo = rand();
	srand(1);
	bar = rand();

You are quite guaranteed that 'foo' and 'bar' are the *SAME*.  The recent
"fix" effectively forced the test case to use the same "random" pkey for
the whole test, unless the test run crossed a second boundary.

Only run srand() once at program startup.

This explains some very odd and persistent test failures I've been seeing.

Link: https://lkml.kernel.org/r/20210611164153.91B76FB8@viggo.jf.intel.com
Link: https://lkml.kernel.org/r/20210611164155.192D00FF@viggo.jf.intel.com
Fixes: 6e373263ce07 ("selftests/vm/pkeys: fix alloc_random_pkey() to make it really random")
Signed-off-by: Dave Hansen 
Signed-off-by: Thomas Gleixner 
Tested-by: Aneesh Kumar K.V 
Cc: Ram Pai 
Cc: Sandipan Das 
Cc: Florian Weimer 
Cc: "Desnes A. Nunes do Rosario" 
Cc: Ingo Molnar 
Cc: Thiago Jung Bauermann 
Cc: Michael Ellerman 
Cc: Michal Hocko 
Cc: Michal Suchanek 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

selftests/vm: gup_test: test faulting in kernel, and verify pinnable pages

2021-05-05T18:27:26+00:00

When pages are pinned they can be faulted in userland and migrated, and
they can be faulted right in kernel without migration.

In either case, the pinned pages must end-up being pinnable (not
movable).

Add a new test to gup_test, to help verify that the gup/pup
(get_user_pages() / pin_user_pages()) behavior with respect to pinnable
and movable pages is reasonable and correct.  Specifically, provide a
way to:

1) Verify that only "pinnable" pages are pinned.  This is checked
   automatically for you.

2) Verify that gup/pup performance is reasonable.  This requires
   comparing benchmarks between doing gup/pup on pages that have been
   pre-faulted in from user space, vs.  doing gup/pup on pages that are
   not faulted in until gup/pup time (via FOLL_TOUCH).  This decision is
   controlled with the new -z command line option.

Link: https://lkml.kernel.org/r/20210215161349.246722-15-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin 
Reviewed-by: John Hubbard 
Cc: Dan Williams 
Cc: David Hildenbrand 
Cc: David Rientjes 
Cc: Ingo Molnar 
Cc: Ira Weiny 
Cc: James Morris 
Cc: Jason Gunthorpe 
Cc: Jason Gunthorpe 
Cc: Joonsoo Kim 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Michal Hocko 
Cc: Mike Kravetz 
Cc: Oscar Salvador 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Steven Rostedt (VMware) 
Cc: Tyler Hicks 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

selftests/vm: gup_test: fix test flag

2021-05-05T18:27:26+00:00

In gup_test both gup_flags and test_flags use the same flags field.
This is broken.

Farther, in the actual gup_test.c all the passed gup_flags are erased
and unconditionally replaced with FOLL_WRITE.

Which means that test_flags are ignored, and code like this always
performs pin dump test:

155  			if (gup->flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)
156  				nr = pin_user_pages(addr, nr, gup->flags,
157  						    pages + i, NULL);
158  			else
159  				nr = get_user_pages(addr, nr, gup->flags,
160  						    pages + i, NULL);
161  			break;

Add a new test_flags field, to allow raw gup_flags to work.  Add a new
subcommand for DUMP_USER_PAGES_TEST to specify that pin test should be
performed.

Remove unconditional overwriting of gup_flags via FOLL_WRITE.  But,
preserve the previous behaviour where FOLL_WRITE was the default flag,
and add a new option "-W" to unset FOLL_WRITE.

Rename flags with gup_flags.

With the fix, dump works like this:

  root@virtme:/# gup_test  -c
  ---- page #0, starting from user virt addr: 0x7f8acb9e4000
  page:00000000d3d2ee27 refcount:2 mapcount:1 mapping:0000000000000000
  index:0x0 pfn:0x100bcf
  anon flags: 0x300000000080016(referenced|uptodate|lru|swapbacked)
  raw: 0300000000080016 ffffd0e204021608 ffffd0e208df2e88 ffff8ea04243ec61
  raw: 0000000000000000 0000000000000000 0000000200000000 0000000000000000
  page dumped because: gup_test: dump_pages() test
  DUMP_USER_PAGES_TEST: done

  root@virtme:/# gup_test  -c -p
  ---- page #0, starting from user virt addr: 0x7fd19701b000
  page:00000000baed3c7d refcount:1025 mapcount:1 mapping:0000000000000000
  index:0x0 pfn:0x108008
  anon flags: 0x300000000080014(uptodate|lru|swapbacked)
  raw: 0300000000080014 ffffd0e204200188 ffffd0e205e09088 ffff8ea04243ee71
  raw: 0000000000000000 0000000000000000 0000040100000000 0000000000000000
  page dumped because: gup_test: dump_pages() test
  DUMP_USER_PAGES_TEST: done

Refcount shows the difference between pin vs no-pin case.
Also change type of nr from int to long, as it counts number of pages.

Link: https://lkml.kernel.org/r/20210215161349.246722-14-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin 
Reviewed-by: John Hubbard 
Cc: Dan Williams 
Cc: David Hildenbrand 
Cc: David Rientjes 
Cc: Ingo Molnar 
Cc: Ira Weiny 
Cc: James Morris 
Cc: Jason Gunthorpe 
Cc: Jason Gunthorpe 
Cc: Joonsoo Kim 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Michal Hocko 
Cc: Mike Kravetz 
Cc: Oscar Salvador 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Steven Rostedt (VMware) 
Cc: Tyler Hicks 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

userfaultfd/selftests: add test exercising minor fault handling

2021-05-05T18:27:23+00:00

Fix a dormant bug in userfaultfd_events_test(), where we did `return
faulting_process(0)` instead of `exit(faulting_process(0))`.  This
caused the forked process to keep running, trying to execute any further
test cases after the events test in parallel with the "real" process.

Add a simple test case which exercises minor faults.  In short, it does
the following:

1. "Sets up" an area (area_dst) and a second shared mapping to the same
   underlying pages (area_dst_alias).

2. Register one of these areas with userfaultfd, in minor fault mode.

3. Start a second thread to handle any minor faults.

4. Populate the underlying pages with the non-UFFD-registered side of
   the mapping. Basically, memset() each page with some arbitrary
   contents.

5. Then, using the UFFD-registered mapping, read all of the page
   contents, asserting that the contents match expectations (we expect
   the minor fault handling thread can modify the page contents before
   resolving the fault).

The minor fault handling thread, upon receiving an event, flips all the
bits (~) in that page, just to prove that it can modify it in some
arbitrary way.  Then it issues a UFFDIO_CONTINUE ioctl, to setup the
mapping and resolve the fault.  The reading thread should wake up and
see this modification.

Currently the minor fault test is only enabled in hugetlb_shared mode,
as this is the only configuration the kernel feature supports.

Link: https://lkml.kernel.org/r/20210301222728.176417-7-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen 
Reviewed-by: Peter Xu 
Cc: Adam Ruprecht 
Cc: Alexander Viro 
Cc: Alexey Dobriyan 
Cc: Andrea Arcangeli 
Cc: Anshuman Khandual 
Cc: Cannon Matthews 
Cc: Catalin Marinas 
Cc: Chinwen Chang 
Cc: David Rientjes 
Cc: "Dr . David Alan Gilbert" 
Cc: Huang Ying 
Cc: Ingo Molnar 
Cc: Jann Horn 
Cc: Jerome Glisse 
Cc: Kirill A. Shutemov 
Cc: Lokesh Gidra 
Cc: "Matthew Wilcox (Oracle)" 
Cc: Michael Ellerman 
Cc: "Michal Koutn" 
Cc: Michel Lespinasse 
Cc: Mike Kravetz 
Cc: Mike Rapoport 
Cc: Mina Almasry 
Cc: Nicholas Piggin 
Cc: Oliver Upton 
Cc: Shaohua Li 
Cc: Shawn Anastasio 
Cc: Steven Price 
Cc: Steven Rostedt 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: huge_memory: debugfs for file-backed THP split

2021-05-05T18:27:21+00:00

Further extend /split_huge_pages to accept
",," for file-backed THP split tests since
tmpfs may have file backed by THP that mapped nowhere.

Update selftest program to test file-backed THP split too.

Link: https://lkml.kernel.org/r/20210331235309.332292-2-zi.yan@sent.com
Signed-off-by: Zi Yan 
Suggested-by: Kirill A. Shutemov 
Reviewed-by: Yang Shi 
Cc: "Kirill A . Shutemov" 
Cc: Shuah Khan 
Cc: John Hubbard 
Cc: Sandipan Das 
Cc: David Hildenbrand 
Cc: Mika Penttila 
Cc: David Rientjes 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: huge_memory: a new debugfs interface for splitting THP tests

2021-05-05T18:27:21+00:00

We did not have a direct user interface of splitting the compound page
backing a THP and there is no need unless we want to expose the THP
implementation details to users.  Make /split_huge_pages accept a
new command to do that.

By writing ",," to
/split_huge_pages, THPs within the given virtual address range
from the process with the given pid are split. It is used to test
split_huge_page function. In addition, a selftest program is added to
tools/testing/selftests/vm to utilize the interface by splitting
PMD THPs and PTE-mapped THPs.

This does not change the old behavior, i.e., writing 1 to the interface
to split all THPs in the system.

Link: https://lkml.kernel.org/r/20210331235309.332292-1-zi.yan@sent.com
Signed-off-by: Zi Yan 
Reviewed-by: Yang Shi 
Cc: David Hildenbrand 
Cc: David Rientjes 
Cc: John Hubbard 
Cc: "Kirill A . Shutemov" 
Cc: Matthew Wilcox 
Cc: Mika Penttila 
Cc: Sandipan Das 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vm/test_vmalloc.sh: adapt for updated driver interface

2021-04-30T18:20:40+00:00

A 'single_cpu_test' parameter is odd and it does not exist anymore.
Instead there was introduced a 'nr_threads' one.  If it is not set it
behaves as the former parameter.

That is why update a "stress mode" according to this change specifying
number of workers which are equal to number of CPUs.  Also update an
output of help message based on a new interface.

Link: https://lkml.kernel.org/r/20210402202237.20334-3-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) 
Cc: Shuah Khan 
Cc: Hillf Danton 
Cc: Matthew Wilcox 
Cc: Michal Hocko 
Cc: Oleksiy Avramchenko 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

selftests: add a MREMAP_DONTUNMAP selftest for shmem

2021-04-30T18:20:39+00:00

This test extends the current mremap tests to validate that the
MREMAP_DONTUNMAP operation can be performed on shmem mappings.

Link: https://lkml.kernel.org/r/20210323182520.2712101-3-bgeffon@google.com
Signed-off-by: Brian Geffon 
Cc: Axel Rasmussen 
Cc: Lokesh Gidra 
Cc: Mike Rapoport 
Cc: Peter Xu 
Cc: Hugh Dickins 
Cc: "Michael S . Tsirkin" 
Cc: Brian Geffon 
Cc: Andy Lutomirski 
Cc: Vlastimil Babka 
Cc: Andrea Arcangeli 
Cc: Sonny Rao 
Cc: Minchan Kim 
Cc: "Kirill A . Shutemov" 
Cc: Dmitry Safonov 
Cc: Michael Kerrisk 
Cc: Alejandro Colomar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds