<feed xmlns='http://www.w3.org/2005/Atom'>
<title>blaster4385/linux-IllusionX/tools/testing/selftests/mm/Makefile, branch v6.12.1</title>
<subtitle>Linux kernel with personal config changes for arch linux</subtitle>
<id>http://git.tablaster.dev/blaster4385/linux-IllusionX/atom?h=v6.12.1</id>
<link rel='self' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/atom?h=v6.12.1'/>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/'/>
<updated>2024-09-21T14:29:05Z</updated>
<entry>
<title>Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2024-09-21T14:29:05Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-09-21T14:29:05Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=617a814f14b8914271f7a70366d72c6196d17663'/>
<id>urn:sha1:617a814f14b8914271f7a70366d72c6196d17663</id>
<content type='text'>
Pull MM updates from Andrew Morton:
 "Along with the usual shower of singleton patches, notable patch series
  in this pull request are:

   - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
     consistency to the APIs and behaviour of these two core allocation
     functions. This also simplifies/enables Rustification.

   - "Some cleanups for shmem" from Baolin Wang. No functional changes -
     mode code reuse, better function naming, logic simplifications.

   - "mm: some small page fault cleanups" from Josef Bacik. No
     functional changes - code cleanups only.

   - "Various memory tiering fixes" from Zi Yan. A small fix and a
     little cleanup.

   - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
     simplifications and .text shrinkage.

   - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
     Butt. This is a feature, it adds new feilds to /proc/vmstat such as

       $ grep kstack /proc/vmstat
       kstack_1k 3
       kstack_2k 188
       kstack_4k 11391
       kstack_8k 243
       kstack_16k 0

     which tells us that 11391 processes used 4k of stack while none at
     all used 16k. Useful for some system tuning things, but
     partivularly useful for "the dynamic kernel stack project".

   - "kmemleak: support for percpu memory leak detect" from Pavel
     Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

   - "mm: memcg: page counters optimizations" from Roman Gushchin. "3
     independent small optimizations of page counters".

   - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
     David Hildenbrand. Improves PTE/PMD splitlock detection, makes
     powerpc/8xx work correctly by design rather than by accident.

   - "mm: remove arch_make_page_accessible()" from David Hildenbrand.
     Some folio conversions which make arch_make_page_accessible()
     unneeded.

   - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
     Finkel. Cleans up and fixes our handling of the resetting of the
     cgroup/process peak-memory-use detector.

   - "Make core VMA operations internal and testable" from Lorenzo
     Stoakes. Rationalizaion and encapsulation of the VMA manipulation
     APIs. With a view to better enable testing of the VMA functions,
     even from a userspace-only harness.

   - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
     issues in the zswap global shrinker, resulting in improved
     performance.

   - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
     in some missing info in /proc/zoneinfo.

   - "mm: replace follow_page() by folio_walk" from David Hildenbrand.
     Code cleanups and rationalizations (conversion to folio_walk())
     resulting in the removal of follow_page().

   - "improving dynamic zswap shrinker protection scheme" from Nhat
     Pham. Some tuning to improve zswap's dynamic shrinker. Significant
     reductions in swapin and improvements in performance are shown.

   - "mm: Fix several issues with unaccepted memory" from Kirill
     Shutemov. Improvements to the new unaccepted memory feature,

   - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
     DAX PUDs. This was missing, although nobody seems to have notied
     yet.

   - "Introduce a store type enum for the Maple tree" from Sidhartha
     Kumar. Cleanups and modest performance improvements for the maple
     tree library code.

   - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
     more cgroup v1 remnants away from the v2 memcg code.

   - "memcg: initiate deprecation of v1 features" from Shakeel Butt.
     Adds various warnings telling users that memcg v1 features are
     deprecated.

   - "mm: swap: mTHP swap allocator base on swap cluster order" from
     Chris Li. Greatly improves the success rate of the mTHP swap
     allocation.

   - "mm: introduce numa_memblks" from Mike Rapoport. Moves various
     disparate per-arch implementations of numa_memblk code into generic
     code.

   - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
     improves the performance of munmap() of swap-filled ptes.

   - "support large folio swap-out and swap-in for shmem" from Baolin
     Wang. With this series we no longer split shmem large folios into
     simgle-page folios when swapping out shmem.

   - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
     performance improvements and code reductions for gigantic folios.

   - "support shmem mTHP collapse" from Baolin Wang. Adds support for
     khugepaged's collapsing of shmem mTHP folios.

   - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
     performance regression due to the addition of mseal().

   - "Increase the number of bits available in page_type" from Matthew
     Wilcox. Increases the number of bits available in page_type!

   - "Simplify the page flags a little" from Matthew Wilcox. Many legacy
     page flags are now folio flags, so the page-based flags and their
     accessors/mutators can be removed.

   - "mm: store zero pages to be swapped out in a bitmap" from Usama
     Arif. An optimization which permits us to avoid writing/reading
     zero-filled zswap pages to backing store.

   - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
     window which occurs when a MAP_FIXED operqtion is occurring during
     an unrelated vma tree walk.

   - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
     the vma_merge() functionality, making ot cleaner, more testable and
     better tested.

   - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
     Minor fixups of DAMON selftests and kunit tests.

   - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
     Code cleanups and folio conversions.

   - "Shmem mTHP controls and stats improvements" from Ryan Roberts.
     Cleanups for shmem controls and stats.

   - "mm: count the number of anonymous THPs per size" from Barry Song.
     Expose additional anon THP stats to userspace for improved tuning.

   - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
     folio conversions and removal of now-unused page-based APIs.

   - "replace per-quota region priorities histogram buffer with
     per-context one" from SeongJae Park. DAMON histogram
     rationalization.

   - "Docs/damon: update GitHub repo URLs and maintainer-profile" from
     SeongJae Park. DAMON documentation updates.

   - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
     improve related doc and warn" from Jason Wang: fixes usage of page
     allocator __GFP_NOFAIL and GFP_ATOMIC flags.

   - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
     This was overprovisioning THPs in sparsely accessed memory areas.

   - "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
     Add support for zram run-time compression algorithm tuning.

   - "mm: Care about shadow stack guard gap when getting an unmapped
     area" from Mark Brown. Fix up the various arch_get_unmapped_area()
     implementations to better respect guard areas.

   - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
     of mem_cgroup_iter() and various code cleanups.

   - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
     pfnmap support.

   - "resource: Fix region_intersects() vs add_memory_driver_managed()"
     from Huang Ying. Fix a bug in region_intersects() for systems with
     CXL memory.

   - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
     a couple more code paths to correctly recover from the encountering
     of poisoned memry.

   - "mm: enable large folios swap-in support" from Barry Song. Support
     the swapin of mTHP memory into appropriately-sized folios, rather
     than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
  zram: free secondary algorithms names
  uprobes: turn xol_area-&gt;pages[2] into xol_area-&gt;page
  uprobes: introduce the global struct vm_special_mapping xol_mapping
  Revert "uprobes: use vm_special_mapping close() functionality"
  mm: support large folios swap-in for sync io devices
  mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
  mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
  mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
  set_memory: add __must_check to generic stubs
  mm/vma: return the exact errno in vms_gather_munmap_vmas()
  memcg: cleanup with !CONFIG_MEMCG_V1
  mm/show_mem.c: report alloc tags in human readable units
  mm: support poison recovery from copy_present_page()
  mm: support poison recovery from do_cow_fault()
  resource, kunit: add test case for region_intersects()
  resource: make alloc_free_mem_region() works for iomem_resource
  mm: z3fold: deprecate CONFIG_Z3FOLD
  vfio/pci: implement huge_fault support
  mm/arm64: support large pfn mappings
  mm/x86: support large pfn mappings
  ...
</content>
</entry>
<entry>
<title>Merge tag 'x86-mm-2024-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2024-09-17T13:03:01Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-09-17T13:03:01Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=70f43ea3a360c5a7d3474b0cfbabb80be6424596'/>
<id>urn:sha1:70f43ea3a360c5a7d3474b0cfbabb80be6424596</id>
<content type='text'>
Pull x86 memory management updates from Thomas Gleixner:

 - Make LAM enablement safe vs. kernel threads using a process mm
   temporarily as switching back to the process would not update CR3 and
   therefore not enable LAM causing faults in user space when using
   tagged pointers. Cure it by synchronizing LAM enablement via IPIs to
   all CPUs which use the related mm.

 - Cure a LAM harmless inconsistency between CR3 and the state during
   context switch. It's both confusing and prone to lead to real bugs

 - Handle alt stack handling for threads which run with a non-zero
   protection key. The non-zero key prevents the kernel to access the
   alternate stack. Cure it by temporarily enabling all protection keys
   for the alternate stack setup/restore operations.

 - Provide a EFI config table identity mapping for kexec kernel to
   prevent kexec fails because the new kernel cannot access the config
   table array

 - Use GB pages only when a full GB is mapped in the identity map as
   otherwise the CPU can speculate into reserved areas after the end of
   memory which causes malfunction on UV systems.

 - Remove the noisy and pointless SRAT table dump during boot

 - Use is_ioremap_addr() for iounmap() address range checks instead of
   high_memory. is_ioremap_addr() is more precise.

* tag 'x86-mm-2024-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ioremap: Improve iounmap() address range checks
  x86/mm: Remove duplicate check from build_cr3()
  x86/mm: Remove unused NX related declarations
  x86/mm: Remove unused CR3_HW_ASID_BITS
  x86/mm: Don't print out SRAT table information
  x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
  x86/kexec: Add EFI config table identity mapping for kexec kernel
  selftests/mm: Add new testcases for pkeys
  x86/pkeys: Restore altstack access in sigreturn()
  x86/pkeys: Update PKRU to enable all pkeys before XSAVE
  x86/pkeys: Add helper functions to update PKRU on the sigframe
  x86/pkeys: Add PKRU as a parameter in signal handling functions
  x86/mm: Cleanup prctl_enable_tagged_addr() nr_bits error checking
  x86/mm: Fix LAM inconsistency during context switch
  x86/mm: Use IPIs to synchronize LAM enablement
</content>
</entry>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2024-09-16T04:55:07Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-09-16T04:55:07Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=114143a595895c03fbefccfd8346fc51fb4908ed'/>
<id>urn:sha1:114143a595895c03fbefccfd8346fc51fb4908ed</id>
<content type='text'>
Pull arm64 updates from Will Deacon:
 "The highlights are support for Arm's "Permission Overlay Extension"
  using memory protection keys, support for running as a protected guest
  on Android as well as perf support for a bunch of new interconnect
  PMUs.

  Summary:

  ACPI:
   - Enable PMCG erratum workaround for HiSilicon HIP10 and 11
     platforms.
   - Ensure arm64-specific IORT header is covered by MAINTAINERS.

  CPU Errata:
   - Enable workaround for hardware access/dirty issue on Ampere-1A
     cores.

  Memory management:
   - Define PHYSMEM_END to fix a crash in the amdgpu driver.
   - Avoid tripping over invalid kernel mappings on the kexec() path.
   - Userspace support for the Permission Overlay Extension (POE) using
     protection keys.

  Perf and PMUs:
   - Add support for the "fixed instruction counter" extension in the
     CPU PMU architecture.
   - Extend and fix the event encodings for Apple's M1 CPU PMU.
   - Allow LSM hooks to decide on SPE permissions for physical
     profiling.
   - Add support for the CMN S3 and NI-700 PMUs.

  Confidential Computing:
   - Add support for booting an arm64 kernel as a protected guest under
     Android's "Protected KVM" (pKVM) hypervisor.

  Selftests:
   - Fix vector length issues in the SVE/SME sigreturn tests
   - Fix build warning in the ptrace tests.

  Timers:
   - Add support for PR_{G,S}ET_TSC so that 'rr' can deal with
     non-determinism arising from the architected counter.

  Miscellaneous:
   - Rework our IPI-based CPU stopping code to try NMIs if regular IPIs
     don't succeed.
   - Minor fixes and cleanups"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (94 commits)
  perf: arm-ni: Fix an NULL vs IS_ERR() bug
  arm64: hibernate: Fix warning for cast from restricted gfp_t
  arm64: esr: Define ESR_ELx_EC_* constants as UL
  arm64: pkeys: remove redundant WARN
  perf: arm_pmuv3: Use BR_RETIRED for HW branch event if enabled
  MAINTAINERS: List Arm interconnect PMUs as supported
  perf: Add driver for Arm NI-700 interconnect PMU
  dt-bindings/perf: Add Arm NI-700 PMU
  perf/arm-cmn: Improve format attr printing
  perf/arm-cmn: Clean up unnecessary NUMA_NO_NODE check
  arm64/mm: use lm_alias() with addresses passed to memblock_free()
  mm: arm64: document why pte is not advanced in contpte_ptep_set_access_flags()
  arm64: Expose the end of the linear map in PHYSMEM_END
  arm64: trans_pgd: mark PTEs entries as valid to avoid dead kexec()
  arm64/mm: Delete __init region from memblock.reserved
  perf/arm-cmn: Support CMN S3
  dt-bindings: perf: arm-cmn: Add CMN S3
  perf/arm-cmn: Refactor DTC PMU register access
  perf/arm-cmn: Make cycle counts less surprising
  perf/arm-cmn: Improve build-time assertion
  ...
</content>
</entry>
<entry>
<title>selftests: mm: make protection_keys test work on arm64</title>
<updated>2024-09-04T11:54:06Z</updated>
<author>
<name>Joey Gouly</name>
<email>joey.gouly@arm.com</email>
</author>
<published>2024-08-22T15:11:09Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=f5b5ea51f78f2ebd94d5a77702bbe5eee8924b50'/>
<id>urn:sha1:f5b5ea51f78f2ebd94d5a77702bbe5eee8924b50</id>
<content type='text'>
The encoding of the pkey register differs on arm64, than on x86/ppc. On those
platforms, a bit in the register is used to disable permissions, for arm64, a
bit enabled in the register indicates that the permission is allowed.

This drops two asserts of the form:
	 assert(read_pkey_reg() &lt;= orig_pkey_reg);
Because on arm64 this doesn't hold, due to the encoding.

The pkey must be reset to both access allow and write allow in the signal
handler. pkey_access_allow() works currently for PowerPC as the
PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE have overlapping bits set.

Access to the uc_mcontext is abstracted, as arm64 has a different structure.

Signed-off-by: Joey Gouly &lt;joey.gouly@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Aneesh Kumar K.V &lt;aneesh.kumar@linux.ibm.com&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20240822151113.1479789-27-joey.gouly@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
</entry>
<entry>
<title>selftests/mm: remove unnecessary ia64 code and comment</title>
<updated>2024-09-04T04:15:38Z</updated>
<author>
<name>Jinjiang Tu</name>
<email>tujinjiang@huawei.com</email>
</author>
<published>2024-08-19T13:06:09Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=2f4db2861013fcfb4be11d0dc176271ae566241c'/>
<id>urn:sha1:2f4db2861013fcfb4be11d0dc176271ae566241c</id>
<content type='text'>
IA64 has gone with commit cf8e8658100d ("arch: Remove Itanium (IA-64)
architecture"), so remove unnecessary ia64 special mm code and comment in
selftests too.

Link: https://lkml.kernel.org/r/20240819130609.3386195-1-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu &lt;tujinjiang@huawei.com&gt;
Cc: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Nanyong Sun &lt;sunnanyong@huawei.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>selftests: memfd_secret: don't build memfd_secret test on unsupported arches</title>
<updated>2024-08-16T05:16:15Z</updated>
<author>
<name>Muhammad Usama Anjum</name>
<email>usama.anjum@collabora.com</email>
</author>
<published>2024-08-09T07:56:42Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=7c5e8d212d7d81991a580e7de3904ea213d9a852'/>
<id>urn:sha1:7c5e8d212d7d81991a580e7de3904ea213d9a852</id>
<content type='text'>
[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 &lt;usama.anjum@collabora.com&gt;
Reviewed-by: Shuah Khan &lt;skhan@linuxfoundation.org&gt;
Acked-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Cc: Albert Ou &lt;aou@eecs.berkeley.edu&gt;
Cc: James Bottomley &lt;James.Bottomley@HansenPartnership.com&gt;
Cc: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>selftests: mm: add s390 to ARCH check</title>
<updated>2024-08-08T01:33:55Z</updated>
<author>
<name>Nico Pache</name>
<email>npache@redhat.com</email>
</author>
<published>2024-07-24T21:35:17Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=30b651c8bc788c068a978dc760e9d5f824f7019e'/>
<id>urn:sha1:30b651c8bc788c068a978dc760e9d5f824f7019e</id>
<content type='text'>
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 &lt;npache@redhat.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Albert Ou &lt;aou@eecs.berkeley.edu&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>selftests/mm: Add new testcases for pkeys</title>
<updated>2024-08-02T12:12:21Z</updated>
<author>
<name>Keith Lucas</name>
<email>keith.lucas@oracle.com</email>
</author>
<published>2024-08-02T06:13:18Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=6998a73efbb8a87f4dd0bddde90b7f5b0d47b5e0'/>
<id>urn:sha1:6998a73efbb8a87f4dd0bddde90b7f5b0d47b5e0</id>
<content type='text'>
Add a few new tests to exercise the signal handler flow, especially with
PKEY 0 disabled:

 - Verify that the SIGSEGV handler is invoked when pkey 0 is disabled.

 - Verify that a thread which disables PKEY 0 segfaults with PKUERR when
   accessing the stack.

 - Verify that the SIGSEGV handler that uses an alternate signal stack is
   correctly invoked when the thread disabled PKEY 0

 - Verify that the PKRU value set by the application is correctly restored
   upon return from signal handling.

 - Verify that sigreturn() is able to restore the altstack even if the
   thread had PKEY 0 disabled

[ Aruna: Adapted to upstream ]
[ tglx: Made it actually compile. Restored protection_keys compile. Added
  	useful info to the changelog instead of bare function names. ]

Signed-off-by: Keith Lucas &lt;keith.lucas@oracle.com&gt;
Signed-off-by: Aruna Ramakrishna &lt;aruna.ramakrishna@oracle.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/all/20240802061318.2140081-6-aruna.ramakrishna@oracle.com
</content>
</entry>
<entry>
<title>Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random</title>
<updated>2024-07-24T17:29:50Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-07-24T17:29:50Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=7a3fad30fd8b4b5e370906b3c554f64026f56c2f'/>
<id>urn:sha1:7a3fad30fd8b4b5e370906b3c554f64026f56c2f</id>
<content type='text'>
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
</content>
</entry>
<entry>
<title>mm: add MAP_DROPPABLE for designating always lazily freeable mappings</title>
<updated>2024-07-19T18:22:12Z</updated>
<author>
<name>Jason A. Donenfeld</name>
<email>Jason@zx2c4.com</email>
</author>
<published>2022-12-08T16:55:04Z</published>
<link rel='alternate' type='text/html' href='http://git.tablaster.dev/blaster4385/linux-IllusionX/commit/?id=9651fcedf7b92d3f7f1ab179e8ab55b85ee10fc1'/>
<id>urn:sha1:9651fcedf7b92d3f7f1ab179e8ab55b85ee10fc1</id>
<content type='text'>
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 &lt;david@redhat.com&gt;
Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
</content>
</entry>
</feed>
