1. 01 Apr, 2017 1 commit
    • Michal Hocko's avatar
      mm: move mm_percpu_wq initialization earlier · 597b7305
      Michal Hocko authored
      Yang Li has reported that drain_all_pages triggers a WARN_ON which means
      that this function is called earlier than the mm_percpu_wq is
      initialized on arm64 with CMA configured:
      
        WARNING: CPU: 2 PID: 1 at mm/page_alloc.c:2423 drain_all_pages+0x244/0x25c
        Modules linked in:
        CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc1-next-20170310-00027-g64dfbc5 #127
        Hardware name: Freescale Layerscape 2088A RDB Board (DT)
        task: ffffffc07c4a6d00 task.stack: ffffffc07c4a8000
        PC is at drain_all_pages+0x244/0x25c
        LR is at start_isolate_page_range+0x14c/0x1f0
        [...]
         drain_all_pages+0x244/0x25c
         start_isolate_page_range+0x14c/0x1f0
         alloc_contig_range+0xec/0x354
         cma_alloc+0x100/0x1fc
         dma_alloc_from_contiguous+0x3c/0x44
         atomic_pool_init+0x7c/0x208
         arm64_dma_init+0x44/0x4c
         do_one_initcall+0x38/0x128
         kernel_init_freeable+0x1a0/0x240
         kernel_init+0x10/0xfc
         ret_from_fork+0x10/0x20
      
      Fix this by moving the whole setup_vmstat which is an initcall right now
      to init_mm_internals which will be called right after the WQ subsystem
      is initialized.
      
      Link: http://lkml.kernel.org/r/20170315164021.28532-1-mhocko@kernel.org
      
      
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
      Reported-by: default avatarYang Li <pku.leo@gmail.com>
      Tested-by: default avatarYang Li <pku.leo@gmail.com>
      Tested-by: default avatarXiaolong Ye <xiaolong.ye@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      597b7305
  2. 09 Mar, 2017 2 commits
  3. 25 Feb, 2017 7 commits
  4. 23 Feb, 2017 12 commits
  5. 11 Jan, 2017 3 commits
  6. 25 Dec, 2016 1 commit
    • Nicholas Piggin's avatar
      mm: add PageWaiters indicating tasks are waiting for a page bit · 62906027
      Nicholas Piggin authored
      
      
      Add a new page flag, PageWaiters, to indicate the page waitqueue has
      tasks waiting. This can be tested rather than testing waitqueue_active
      which requires another cacheline load.
      
      This bit is always set when the page has tasks on page_waitqueue(page),
      and is set and cleared under the waitqueue lock. It may be set when
      there are no tasks on the waitqueue, which will cause a harmless extra
      wakeup check that will clears the bit.
      
      The generic bit-waitqueue infrastructure is no longer used for pages.
      Instead, waitqueues are used directly with a custom key type. The
      generic code was not flexible enough to have PageWaiters manipulation
      under the waitqueue lock (which simplifies concurrency).
      
      This improves the performance of page lock intensive microbenchmarks by
      2-3%.
      
      Putting two bits in the same word opens the opportunity to remove the
      memory barrier between clearing the lock bit and testing the waiters
      bit, after some work on the arch primitives (e.g., ensuring memory
      operand widths match and cover both bits).
      
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Bob Peterson <rpeterso@redhat.com>
      Cc: Steven Whitehouse <swhiteho@redhat.com>
      Cc: Andrew Lutomirski <luto@kernel.org>
      Cc: Andreas Gruenbacher <agruenba@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      62906027
  7. 15 Dec, 2016 10 commits
  8. 22 Nov, 2016 1 commit
    • Eric W. Biederman's avatar
      ptrace: Don't allow accessing an undumpable mm · 84d77d3f
      Eric W. Biederman authored
      
      
      It is the reasonable expectation that if an executable file is not
      readable there will be no way for a user without special privileges to
      read the file.  This is enforced in ptrace_attach but if ptrace
      is already attached before exec there is no enforcement for read-only
      executables.
      
      As the only way to read such an mm is through access_process_vm
      spin a variant called ptrace_access_vm that will fail if the
      target process is not being ptraced by the current process, or
      the current process did not have sufficient privileges when ptracing
      began to read the target processes mm.
      
      In the ptrace implementations replace access_process_vm by
      ptrace_access_vm.  There remain several ptrace sites that still use
      access_process_vm as they are reading the target executables
      instructions (for kernel consumption) or register stacks.  As such it
      does not appear necessary to add a permission check to those calls.
      
      This bug has always existed in Linux.
      
      Fixes: v1.0
      Cc: stable@vger.kernel.org
      Reported-by: default avatarAndy Lutomirski <luto@amacapital.net>
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      84d77d3f
  9. 25 Oct, 2016 1 commit
    • Lorenzo Stoakes's avatar
      mm: unexport __get_user_pages() · 0d731759
      Lorenzo Stoakes authored
      
      
      This patch unexports the low-level __get_user_pages() function.
      
      Recent refactoring of the get_user_pages* functions allow flags to be
      passed through get_user_pages() which eliminates the need for access to
      this function from its one user, kvm.
      
      We can see that the two calls to get_user_pages() which replace
      __get_user_pages() in kvm_main.c are equivalent by examining their call
      stacks:
      
        get_user_page_nowait():
          get_user_pages(start, 1, flags, page, NULL)
          __get_user_pages_locked(current, current->mm, start, 1, page, NULL, NULL,
      			    false, flags | FOLL_TOUCH)
          __get_user_pages(current, current->mm, start, 1,
      		     flags | FOLL_TOUCH | FOLL_GET, page, NULL, NULL)
      
        check_user_page_hwpoison():
          get_user_pages(addr, 1, flags, NULL, NULL)
          __get_user_pages_locked(current, current->mm, addr, 1, NULL, NULL, NULL,
      			    false, flags | FOLL_TOUCH)
          __get_user_pages(current, current->mm, addr, 1, flags | FOLL_TOUCH, NULL,
      		     NULL, NULL)
      
      Signed-off-by: default avatarLorenzo Stoakes <lstoakes@gmail.com>
      Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0d731759
  10. 20 Oct, 2016 1 commit
  11. 19 Oct, 2016 1 commit