linux.git/kernel/fork.c, branch v4.14.34

kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK

2018-02-22T14:42:23+00:00

commit 75f296d93bcebcfe375884ddac79e30263a31766 upstream.

Convert all allocations that used a NOTRACK flag to stop using it.

Link: http://lkml.kernel.org/r/20171007030159.22241-3-alexander.levin@verizon.com
Signed-off-by: Sasha Levin 
Cc: Alexander Potapenko 
Cc: Eric W. Biederman 
Cc: Michal Hocko 
Cc: Pekka Enberg 
Cc: Steven Rostedt 
Cc: Tim Hansen 
Cc: Vegard Nossum 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

arch, mm: Allow arch_dup_mmap() to fail

2017-12-29T16:53:43+00:00

commit c10e83f598d08046dd1ebc8360d4bb12d802d51b upstream.

In order to sanitize the LDT initialization on x86 arch_dup_mmap() must be
allowed to fail. Fix up all instances.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andy Lutomirski 
Cc: Andy Lutomirsky 
Cc: Boris Ostrovsky 
Cc: Borislav Petkov 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Dave Hansen 
Cc: David Laight 
Cc: Denys Vlasenko 
Cc: Eduardo Valentin 
Cc: Greg KH 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Will Deacon 
Cc: aliguori@amazon.com
Cc: dan.j.williams@intel.com
Cc: hughd@google.com
Cc: keescook@google.com
Cc: kirill.shutemov@linux.intel.com
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

kmemleak: clear stale pointers from task stacks

2017-10-13T23:18:33+00:00

Kmemleak considers any pointers on task stacks as references.  This
patch clears newly allocated and reused vmap stacks.

Link: http://lkml.kernel.org/r/150728990124.744199.8403409836394318684.stgit@buzz
Signed-off-by: Konstantin Khlebnikov 
Acked-by: Catalin Marinas 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

android: binder: drop lru lock in isolate callback

2017-10-04T00:54:24+00:00

Drop the global lru lock in isolate callback before calling
zap_page_range which calls cond_resched, and re-acquire the global lru
lock before returning.  Also change return code to LRU_REMOVED_RETRY.

Use mmput_async when fail to acquire mmap sem in an atomic context.

Fix "BUG: sleeping function called from invalid context"
errors when CONFIG_DEBUG_ATOMIC_SLEEP is enabled.

Also restore mmput_async, which was initially introduced in commit
ec8d7c14ea14 ("mm, oom_reaper: do not mmput synchronously from the oom
reaper context"), and was removed in commit 212925802454 ("mm: oom: let
oom_reap_task and exit_mmap run concurrently").

Link: http://lkml.kernel.org/r/20170914182231.90908-1-sherryy@android.com
Fixes: f2517eb76f1f2 ("android: binder: Add global lru shrinker to binder")
Signed-off-by: Sherry Yang 
Signed-off-by: Greg Kroah-Hartman 
Reported-by: Kyle Yan 
Acked-by: Arve Hjønnevåg 
Acked-by: Michal Hocko 
Cc: Martijn Coenen 
Cc: Todd Kjos 
Cc: Riley Andrews 
Cc: Ingo Molnar 
Cc: Vlastimil Babka 
Cc: Hillf Danton 
Cc: Peter Zijlstra 
Cc: Andrea Arcangeli 
Cc: Thomas Gleixner 
Cc: Andy Lutomirski 
Cc: Oleg Nesterov 
Cc: Hoeun Ryu 
Cc: Christopher Lameter 
Cc: Vegard Nossum 
Cc: Frederic Weisbecker 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'selinux-pr-20170831' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

2017-09-12T20:21:00+00:00

Pull selinux updates from Paul Moore:
 "A relatively quiet period for SELinux, 11 patches with only two/three
  having any substantive changes.

  These noteworthy changes include another tweak to the NNP/nosuid
  handling, per-file labeling for cgroups, and an object class fix for
  AF_UNIX/SOCK_RAW sockets; the rest of the changes are minor tweaks or
  administrative updates (Stephen's email update explains the file
  explosion in the diffstat).

  Everything passes the selinux-testsuite"

[ Also a couple of small patches from the security tree from Tetsuo
  Handa for Tomoyo and LSM cleanup. The separation of security policy
  updates wasn't all that clean - Linus ]

* tag 'selinux-pr-20170831' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: constify nf_hook_ops
  selinux: allow per-file labeling for cgroupfs
  lsm_audit: update my email address
  selinux: update my email address
  MAINTAINERS: update the NetLabel and Labeled Networking information
  selinux: use GFP_NOWAIT in the AVC kmem_caches
  selinux: Generalize support for NNP/nosuid SELinux domain transitions
  selinux: genheaders should fail if too many permissions are defined
  selinux: update the selinux info in MAINTAINERS
  credits: update Paul Moore's info
  selinux: Assign proper class to PF_UNIX/SOCK_RAW sockets
  tomoyo: Update URLs in Documentation/admin-guide/LSM/tomoyo.rst
  LSM: Remove security_task_create() hook.

locking/rtmutex: replace top-waiter and pi_waiters leftmost caching

2017-09-09T01:26:49+00:00

... with the generic rbtree flavor instead. No changes
in semantics whatsoever.

Link: http://lkml.kernel.org/r/20170719014603.19029-10-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: heterogeneous memory management (HMM for short)

2017-09-09T01:26:45+00:00

HMM provides 3 separate types of functionality:
    - Mirroring: synchronize CPU page table and device page table
    - Device memory: allocating struct page for device memory
    - Migration: migrating regular memory to device memory

This patch introduces some common helpers and definitions to all of
those 3 functionality.

Link: http://lkml.kernel.org/r/20170817000548.32038-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Signed-off-by: Evgeny Baskakov 
Signed-off-by: John Hubbard 
Signed-off-by: Mark Hairgrove 
Signed-off-by: Sherry Cheung 
Signed-off-by: Subhash Gutti 
Cc: Aneesh Kumar 
Cc: Balbir Singh 
Cc: Benjamin Herrenschmidt 
Cc: Dan Williams 
Cc: David Nellans 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Paul E. McKenney 
Cc: Ross Zwisler 
Cc: Vladimir Davydov 
Cc: Bob Liu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm,fork: introduce MADV_WIPEONFORK

2017-09-07T00:27:30+00:00

Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty
in the child process after fork.  This differs from MADV_DONTFORK in one
important way.

If a child process accesses memory that was MADV_WIPEONFORK, it will get
zeroes.  The address ranges are still valid, they are just empty.

If a child process accesses memory that was MADV_DONTFORK, it will get a
segmentation fault, since those address ranges are no longer valid in
the child after fork.

Since MADV_DONTFORK also seems to be used to allow very large programs
to fork in systems with strict memory overcommit restrictions, changing
the semantics of MADV_DONTFORK might break existing programs.

MADV_WIPEONFORK only works on private, anonymous VMAs.

The use case is libraries that store or cache information, and want to
know that they need to regenerate it in the child process after fork.

Examples of this would be:
 - systemd/pulseaudio API checks (fail after fork) (replacing a getpid
   check, which is too slow without a PID cache)
 - PKCS#11 API reinitialization check (mandated by specification)
 - glibc's upcoming PRNG (reseed after fork)
 - OpenSSL PRNG (reseed after fork)

The security benefits of a forking server having a re-inialized PRNG in
every child process are pretty obvious.  However, due to libraries
having all kinds of internal state, and programs getting compiled with
many different versions of each library, it is unreasonable to expect
calling programs to re-initialize everything manually after fork.

A further complication is the proliferation of clone flags, programs
bypassing glibc's functions to call clone directly, and programs calling
unshare, causing the glibc pthread_atfork hook to not get called.

It would be better to have the kernel take care of this automatically.

The patch also adds MADV_KEEPONFORK, to undo the effects of a prior
MADV_WIPEONFORK.

This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:

    https://man.openbsd.org/minherit.2

[akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines]
Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.com
Signed-off-by: Rik van Riel 
Reported-by: Florian Weimer 
Reported-by: Colm MacCártaigh 
Reviewed-by: Mike Kravetz 
Cc: "H. Peter Anvin" 
Cc: "Kirill A. Shutemov" 
Cc: Andy Lutomirski 
Cc: Dave Hansen 
Cc: Ingo Molnar 
Cc: Helge Deller 
Cc: Kees Cook 
Cc: Matthew Wilcox 
Cc: Thomas Gleixner 
Cc: Will Drewry 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: oom: let oom_reap_task and exit_mmap run concurrently

2017-09-07T00:27:30+00:00

This is purely required because exit_aio() may block and exit_mmap() may
never start, if the oom_reap_task cannot start running on a mm with
mm_users == 0.

At the same time if the OOM reaper doesn't wait at all for the memory of
the current OOM candidate to be freed by exit_mmap->unmap_vmas, it would
generate a spurious OOM kill.

If it wasn't because of the exit_aio or similar blocking functions in
the last mmput, it would be enough to change the oom_reap_task() in the
case it finds mm_users == 0, to wait for a timeout or to wait for
__mmput to set MMF_OOM_SKIP itself, but it's not just exit_mmap the
problem here so the concurrency of exit_mmap and oom_reap_task is
apparently warranted.

It's a non standard runtime, exit_mmap() runs without mmap_sem, and
oom_reap_task runs with the mmap_sem for reading as usual (kind of
MADV_DONTNEED).

The race between the two is solved with a combination of
tsk_is_oom_victim() (serialized by task_lock) and MMF_OOM_SKIP
(serialized by a dummy down_write/up_write cycle on the same lines of
the ksm_exit method).

If the oom_reap_task() may be running concurrently during exit_mmap,
exit_mmap will wait it to finish in down_write (before taking down mm
structures that would make the oom_reap_task fail with use after free).

If exit_mmap comes first, oom_reap_task() will skip the mm if
MMF_OOM_SKIP is already set and in turn all memory is already freed and
furthermore the mm data structures may already have been taken down by
free_pgtables.

[aarcange@redhat.com: incremental one liner]
  Link: http://lkml.kernel.org/r/20170726164319.GC29716@redhat.com
[rientjes@google.com: remove unused mmput_async]
  Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708141733130.50317@chino.kir.corp.google.com
[aarcange@redhat.com: microoptimization]
  Link: http://lkml.kernel.org/r/20170817171240.GB5066@redhat.com
Link: http://lkml.kernel.org/r/20170726162912.GA29716@redhat.com
Fixes: 26db62f179d1 ("oom: keep mm of the killed task available")
Signed-off-by: Andrea Arcangeli 
Signed-off-by: David Rientjes 
Reported-by: David Rientjes 
Tested-by: David Rientjes 
Reviewed-by: Michal Hocko 
Cc: Tetsuo Handa 
Cc: Oleg Nesterov 
Cc: Hugh Dickins 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2017-09-05T16:53:37+00:00

Pull arm64 updates from Catalin Marinas:

 - VMAP_STACK support, allowing the kernel stacks to be allocated in the
   vmalloc space with a guard page for trapping stack overflows. One of
   the patches introduces THREAD_ALIGN and changes the generic
   alloc_thread_stack_node() to use this instead of THREAD_SIZE (no
   functional change for other architectures)

 - Contiguous PTE hugetlb support re-enabled (after being reverted a
   couple of times). We now have the semantics agreed in the generic mm
   layer together with API improvements so that the architecture code
   can detect between contiguous and non-contiguous huge PTEs

 - Initial support for persistent memory on ARM: DC CVAP instruction
   exposed to user space (HWCAP) and the in-kernel pmem API implemented

 - raid6 improvements for arm64: faster algorithm for the delta syndrome
   and implementation of the recovery routines using Neon

 - FP/SIMD refactoring and removal of support for Neon in interrupt
   context. This is in preparation for full SVE support

 - PTE accessors converted from inline asm to cmpxchg so that we can use
   LSE atomics if available (ARMv8.1)

 - Perf support for Cortex-A35 and A73

 - Non-urgent fixes and cleanups

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (75 commits)
  arm64: cleanup {COMPAT_,}SET_PERSONALITY() macro
  arm64: introduce separated bits for mm_context_t flags
  arm64: hugetlb: Cleanup setup_hugepagesz
  arm64: Re-enable support for contiguous hugepages
  arm64: hugetlb: Override set_huge_swap_pte_at() to support contiguous hugepages
  arm64: hugetlb: Override huge_pte_clear() to support contiguous hugepages
  arm64: hugetlb: Handle swap entries in huge_pte_offset() for contiguous hugepages
  arm64: hugetlb: Add break-before-make logic for contiguous entries
  arm64: hugetlb: Spring clean huge pte accessors
  arm64: hugetlb: Introduce pte_pgprot helper
  arm64: hugetlb: set_huge_pte_at Add WARN_ON on !pte_present
  arm64: kexec: have own crash_smp_send_stop() for crash dump for nonpanic cores
  arm64: dma-mapping: Mark atomic_pool as __ro_after_init
  arm64: dma-mapping: Do not pass data to gen_pool_set_algo()
  arm64: Remove the !CONFIG_ARM64_HW_AFDBM alternative code paths
  arm64: Ignore hardware dirty bit updates in ptep_set_wrprotect()
  arm64: Move PTE_RDONLY bit handling out of set_pte_at()
  kvm: arm64: Convert kvm_set_s2pte_readonly() from inline asm to cmpxchg()
  arm64: Convert pte handling from inline asm to using (cmp)xchg
  arm64: neon/efi: Make EFI fpsimd save/restore variables static
  ...