1. 26 Sep, 2016 38 commits
  2. 25 Sep, 2016 2 commits
    • Lorenzo Stoakes's avatar
      mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing · 38e08854
      Lorenzo Stoakes authored
      The NUMA balancing logic uses an arch-specific PROT_NONE page table flag
      defined by pte_protnone() or pmd_protnone() to mark PTEs or huge page
      PMDs respectively as requiring balancing upon a subsequent page fault.
      User-defined PROT_NONE memory regions which also have this flag set will
      not normally invoke the NUMA balancing code as do_page_fault() will send
      a segfault to the process before handle_mm_fault() is even called.
      
      However if access_remote_vm() is invoked to access a PROT_NONE region of
      memory, handle_mm_fault() is called via faultin_page() and
      __get_user_pages() without any access checks being performed, meaning
      the NUMA balancing logic is incorrectly invoked on a non-NUMA memory
      region.
      
      A simple means of triggering this problem is to access PROT_NONE mmap'd
      memory using /proc/self/mem which reliably results in the NUMA handling
      functions being invoked when CONFIG_NUMA_BALANCING is set.
      
      This issue was reported in bugzilla (issue 99101) which includes some
      simple repro code.
      
      There are BUG_ON() checks in do_numa_page() and do_huge_pmd_numa_page()
      added at commit c0e7cad9 to avoid accidentally provoking strange
      behaviour by attempting to apply NUMA balancing to pages that are in
      fact PROT_NONE.  The BUG_ON()'s are consistently triggered by the repro.
      
      This patch moves the PROT_NONE check into mm/memory.c rather than
      invoking BUG_ON() as faulting in these pages via faultin_page() is a
      valid reason for reaching the NUMA check with the PROT_NONE page table
      flag set and is therefore not always a bug.
      
      Link: https://bugzilla.kernel.org/show_bug.cgi?id=99101Reported-by: default avatarTrevor Saunders <tbsaunde@tbsaunde.org>
      Signed-off-by: default avatarLorenzo Stoakes <lstoakes@gmail.com>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      38e08854
    • Linus Torvalds's avatar
      Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus · 831e45d8
      Linus Torvalds authored
      Pull MIPS fixes from Ralf Baechle:
       "A round of 4.8 fixes:
      
        MIPS generic code:
         - Add a missing ".set pop" in an early commit
         - Fix memory regions reaching top of physical
         - MAAR: Fix address alignment
         - vDSO: Fix Malta EVA mapping to vDSO page structs
         - uprobes: fix incorrect uprobe brk handling
         - uprobes: select HAVE_REGS_AND_STACK_ACCESS_API
         - Avoid a BUG warning during PR_SET_FP_MODE prctl
         - SMP: Fix possibility of deadlock when bringing CPUs online
         - R6: Remove compact branch policy Kconfig entries
         - Fix size calc when avoiding IPIs for small icache flushes
         - Fix pre-r6 emulation FPU initialisation
         - Fix delay slot emulation count in debugfs
      
        ATH79:
         - Fix test for error return of clk_register_fixed_factor.
      
        Octeon:
         - Fix kernel header to work for VDSO build.
         - Fix initialization of platform device probing.
      
        paravirt:
         - Fix undefined reference to smp_bootstrap"
      
      * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
        MIPS: Fix delay slot emulation count in debugfs
        MIPS: SMP: Fix possibility of deadlock when bringing CPUs online
        MIPS: Fix pre-r6 emulation FPU initialisation
        MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs
        MIPS: Select HAVE_REGS_AND_STACK_ACCESS_API
        MIPS: Octeon: Fix platform bus probing
        MIPS: Octeon: mangle-port: fix build failure with VDSO code
        MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)
        MIPS: c-r4k: Fix size calc when avoiding IPIs for small icache flushes
        MIPS: Add a missing ".set pop" in an early commit
        MIPS: paravirt: Fix undefined reference to smp_bootstrap
        MIPS: Remove compact branch policy Kconfig entries
        MIPS: MAAR: Fix address alignment
        MIPS: Fix memory regions reaching top of physical
        MIPS: uprobes: fix incorrect uprobe brk handling
        MIPS: ath79: Fix test for error return of clk_register_fixed_factor().
      831e45d8