linux.git/tools/testing/selftests/mm, branch v6.11

selftests: mm: fix build errors on armhf

2024-09-02T00:58:59+00:00

The __NR_mmap isn't found on armhf.  The mmap() is commonly available
system call and its wrapper is present on all architectures.  So it should
be used directly.  It solves problem for armhf and doesn't create problem
for other architectures.

Remove sys_mmap() functions as they aren't doing anything else other than
calling mmap().  There is no need to set errno = 0 manually as glibc
always resets it.

For reference errors are as following:

  CC       seal_elf
seal_elf.c: In function 'sys_mmap':
seal_elf.c:39:33: error: '__NR_mmap' undeclared (first use in this function)
   39 |         sret = (void *) syscall(__NR_mmap, addr, len, prot,
      |                                 ^~~~~~~~~

mseal_test.c: In function 'sys_mmap':
mseal_test.c:90:33: error: '__NR_mmap' undeclared (first use in this function)
   90 |         sret = (void *) syscall(__NR_mmap, addr, len, prot,
      |                                 ^~~~~~~~~

Link: https://lkml.kernel.org/r/20240809082511.497266-1-usama.anjum@collabora.com
Fixes: 4926c7a52de7 ("selftest mm/mseal memory sealing")
Signed-off-by: Muhammad Usama Anjum 
Cc: Jeff Xu 
Cc: Kees Cook 
Cc: Liam R. Howlett 
Cc: Shuah Khan 
Cc: 
Signed-off-by: Andrew Morton

selftests: memfd_secret: don't build memfd_secret test on unsupported arches

2024-08-16T05:16:15+00:00

[1] mentions that memfd_secret is only supported on arm64, riscv, x86 and
x86_64 for now.  It doesn't support other architectures.  I found the
build error on arm and decided to send the fix as it was creating noise on
KernelCI:

memfd_secret.c: In function 'memfd_secret':
memfd_secret.c:42:24: error: '__NR_memfd_secret' undeclared (first use in this function);
did you mean 'memfd_secret'?
   42 |         return syscall(__NR_memfd_secret, flags);
      |                        ^~~~~~~~~~~~~~~~~
      |                        memfd_secret

Hence I'm adding condition that memfd_secret should only be compiled on
supported architectures.

Also check in run_vmtests script if memfd_secret binary is present before
executing it.

Link: https://lkml.kernel.org/r/20240812061522.1933054-1-usama.anjum@collabora.com
Link: https://lore.kernel.org/all/20210518072034.31572-7-rppt@kernel.org/ [1]
Link: https://lkml.kernel.org/r/20240809075642.403247-1-usama.anjum@collabora.com
Fixes: 76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)")
Signed-off-by: Muhammad Usama Anjum 
Reviewed-by: Shuah Khan 
Acked-by: Mike Rapoport (Microsoft) 
Cc: Albert Ou 
Cc: James Bottomley 
Cc: Mike Rapoport (Microsoft) 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: 
Signed-off-by: Andrew Morton

selftests/mm: compaction_test: fix off by one in check_compaction()

2024-08-16T05:16:15+00:00

The "initial_nr_hugepages" variable is unsigned long so it takes up to 20
characters to print, plus 1 more character for the NUL terminator. 
Unfortunately, this buffer is not quite large enough for the terminator to
fit.  Also use snprintf() for a belt and suspenders approach.

Link: https://lkml.kernel.org/r/87470c06-b45a-4e83-92ff-aac2e7b9c6ba@stanley.mountain
Fixes: fb9293b6b015 ("selftests/mm: compaction_test: fix bogus test success and reduce probability of OOM-killer invocation")
Signed-off-by: Dan Carpenter 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

Merge tag 'mm-hotfixes-stable-2024-08-07-18-32' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-08-08T14:32:20+00:00

Pull misc fixes from Andrew Morton:
 "Nine hotfixes. Five are cc:stable, the others either pertain to
  post-6.10 material or aren't considered necessary for earlier kernels.

  Five are MM and four are non-MM. No identifiable theme here - please
  see the individual changelogs"

* tag 'mm-hotfixes-stable-2024-08-07-18-32' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  padata: Fix possible divide-by-0 panic in padata_mt_helper()
  mailmap: update entry for David Heidelberg
  memcg: protect concurrent access to mem_cgroup_idr
  mm: shmem: fix incorrect aligned index when checking conflicts
  mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem
  mm: list_lru: fix UAF for memory cgroup
  kcov: properly check for softirq context
  MAINTAINERS: Update LTP members and web
  selftests: mm: add s390 to ARCH check

selftests: mm: add s390 to ARCH check

2024-08-08T01:33:55+00:00

commit 0518dbe97fe6 ("selftests/mm: fix cross compilation with LLVM")
changed the env variable for the architecture from MACHINE to ARCH.

This is preventing 3 required TEST_GEN_FILES from being included when
cross compiling s390x and errors when trying to run the test suite.  This
is due to the ARCH variable already being set and the arch folder name
being s390.

Add "s390" to the filtered list to cover this case and have the 3 files
included in the build.

Link: https://lkml.kernel.org/r/20240724213517.23918-1-npache@redhat.com
Fixes: 0518dbe97fe6 ("selftests/mm: fix cross compilation with LLVM")
Signed-off-by: Nico Pache 
Cc: Mark Brown 
Cc: Albert Ou 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Shuah Khan 
Cc: 
Signed-off-by: Andrew Morton

minmax: make generic MIN() and MAX() macros available everywhere

2024-07-28T22:49:18+00:00

This just standardizes the use of MIN() and MAX() macros, with the very
traditional semantics.  The goal is to use these for C constant
expressions and for top-level / static initializers, and so be able to
simplify the min()/max() macros.

These macro names were used by various kernel code - they are very
traditional, after all - and all such users have been fixed up, with a
few different approaches:

 - trivial duplicated macro definitions have been removed

   Note that 'trivial' here means that it's obviously kernel code that
   already included all the major kernel headers, and thus gets the new
   generic MIN/MAX macros automatically.

 - non-trivial duplicated macro definitions are guarded with #ifndef

   This is the "yes, they define their own versions, but no, the include
   situation is not entirely obvious, and maybe they don't get the
   generic version automatically" case.

 - strange use case #1

   A couple of drivers decided that the way they want to describe their
   versioning is with

	#define MAJ 1
	#define MIN 2
	#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)

   which adds zero value and I just did my Alexander the Great
   impersonation, and rewrote that pointless Gordian knot as

	#define DRV_VERSION "1.2"

   instead.

 - strange use case #2

   A couple of drivers thought that it's a good idea to have a random
   'MIN' or 'MAX' define for a value or index into a table, rather than
   the traditional macro that takes arguments.

   These values were re-written as C enum's instead. The new
   function-line macros only expand when followed by an open
   parenthesis, and thus don't clash with enum use.

Happily, there weren't really all that many of these cases, and a lot of
users already had the pattern of using '#ifndef' guarding (or in one
case just using '#undef MIN') before defining their own private version
that does the same thing. I left such cases alone.

Cc: David Laight 
Cc: Lorenzo Stoakes 
Signed-off-by: Linus Torvalds

selftests/mm: skip test for non-LPA2 and non-LVA systems

2024-07-26T21:33:10+00:00

Post my improvement of the test in e4a4ba415419 ("selftests/mm:
va_high_addr_switch: dynamically initialize testcases to enable LPA2
testing"):

The test begins to fail on 4k and 16k pages, on non-LPA2 systems.  To
reduce noise in the CI systems, let us skip the test when higher address
space is not implemented.

Link: https://lkml.kernel.org/r/20240718052504.356517-1-dev.jain@arm.com
Fixes: e4a4ba415419 ("selftests/mm: va_high_addr_switch: dynamically initialize testcases to enable LPA2 testing")
Signed-off-by: Dev Jain 
Reviewed-by: Ryan Roberts 
Cc: Anshuman Khandual 
Cc: Mark Brown 
Signed-off-by: Andrew Morton

Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

2024-07-24T17:29:50+00:00

Pull random number generator updates from Jason Donenfeld:
 "This adds getrandom() support to the vDSO.

  First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
  lets the kernel zero out pages anytime under memory pressure, which
  enables allocating memory that never gets swapped to disk but also
  doesn't count as being mlocked.

  Then, the vDSO implementation of getrandom() is introduced in a
  generic manner and hooked into random.c.

  Next, this is implemented on x86. (Also, though it's not ready for
  this pull, somebody has begun an arm64 implementation already)

  Finally, two vDSO selftests are added.

  There are also two housekeeping cleanup commits"

* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  MAINTAINERS: add random.h headers to RNG subsection
  random: note that RNDGETPOOL was removed in 2.6.9-rc2
  selftests/vDSO: add tests for vgetrandom
  x86: vdso: Wire up getrandom() vDSO implementation
  random: introduce generic vDSO getrandom() implementation
  mm: add MAP_DROPPABLE for designating always lazily freeable mappings

mm: add MAP_DROPPABLE for designating always lazily freeable mappings

2024-07-19T18:22:12+00:00

The vDSO getrandom() implementation works with a buffer allocated with a
new system call that has certain requirements:

- It shouldn't be written to core dumps.
  * Easy: VM_DONTDUMP.
- It should be zeroed on fork.
  * Easy: VM_WIPEONFORK.

- It shouldn't be written to swap.
  * Uh-oh: mlock is rlimited.
  * Uh-oh: mlock isn't inherited by forks.

- It shouldn't reserve actual memory, but it also shouldn't crash when
  page faulting in memory if none is available
  * Uh-oh: VM_NORESERVE means segfaults.

It turns out that the vDSO getrandom() function has three really nice
characteristics that we can exploit to solve this problem:

1) Due to being wiped during fork(), the vDSO code is already robust to
   having the contents of the pages it reads zeroed out midway through
   the function's execution.

2) In the absolute worst case of whatever contingency we're coding for,
   we have the option to fallback to the getrandom() syscall, and
   everything is fine.

3) The buffers the function uses are only ever useful for a maximum of
   60 seconds -- a sort of cache, rather than a long term allocation.

These characteristics mean that we can introduce VM_DROPPABLE, which
has the following semantics:

a) It never is written out to swap.
b) Under memory pressure, mm can just drop the pages (so that they're
   zero when read back again).
c) It is inherited by fork.
d) It doesn't count against the mlock budget, since nothing is locked.
e) If there's not enough memory to service a page fault, it's not fatal,
   and no signal is sent.

This way, allocations used by vDSO getrandom() can use:

    VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE

And there will be no problem with OOMing, crashing on overcommitment,
using memory when not in use, not wiping on fork(), coredumps, or
writing out to swap.

In order to let vDSO getrandom() use this, expose these via mmap(2) as
MAP_DROPPABLE.

Note that this involves removing the MADV_FREE special case from
sort_folio(), which according to Yu Zhao is unnecessary and will simply
result in an extra call to shrink_folio_list() in the worst case. The
chunk removed reenables the swapbacked flag, which we don't want for
VM_DROPPABLE, and we can't conditionalize it here because there isn't a
vma reference available.

Finally, the provided self test ensures that this is working as desired.

Cc: linux-mm@kvack.org
Acked-by: David Hildenbrand 
Signed-off-by: Jason A. Donenfeld

selftests: centralize -D_GNU_SOURCE= to CFLAGS in lib.mk

2024-07-10T19:14:51+00:00

Centralize the _GNU_SOURCE definition to CFLAGS in lib.mk.  Remove
redundant defines from Makefiles that import lib.mk.  Convert any usage of
"#define _GNU_SOURCE 1" to "#define _GNU_SOURCE".

This uses the form "-D_GNU_SOURCE=", which is equivalent to
"#define _GNU_SOURCE".

Otherwise using "-D_GNU_SOURCE" is equivalent to "-D_GNU_SOURCE=1" and
"#define _GNU_SOURCE 1", which is less commonly seen in source code and
would require many changes in selftests to avoid redefinition warnings.

Link: https://lkml.kernel.org/r/20240625223454.1586259-2-edliaw@google.com
Signed-off-by: Edward Liaw 
Suggested-by: John Hubbard 
Acked-by: Shuah Khan 
Reviewed-by: Muhammad Usama Anjum 
Cc: Albert Ou 
Cc: André Almeida 
Cc: Darren Hart 
Cc: Dave Hansen 
Cc: Davidlohr Bueso 
Cc: David S. Miller 
Cc: Eric Dumazet 
Cc: Eric W. Biederman 
Cc: Fenghua Yu 
Cc: Ingo Molnar 
Cc: Jakub Kicinski 
Cc: Jarkko Sakkinen 
Cc: Jason Gunthorpe 
Cc: Kees Cook 
Cc: Kevin Tian 
Cc: Palmer Dabbelt 
Cc: Paolo Abeni 
Cc: Paolo Bonzini 
Cc: Paul Walmsley 
Cc: Peter Zijlstra 
Cc: Reinette Chatre 
Cc: Sean Christopherson 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton