1. 16 Nov, 2012 12 commits
    • Andrew Morton's avatar
      revert "mm: fix-up zone present pages" · 5576646f
      Andrew Morton authored
      Revert commit 7f1290f2 ("mm: fix-up zone present pages")
      
      That patch tried to fix a issue when calculating zone->present_pages,
      but it caused a regression on 32bit systems with HIGHMEM.  With that
      change, reset_zone_present_pages() resets all zone->present_pages to
      zero, and fixup_zone_present_pages() is called to recalculate
      zone->present_pages when the boot allocator frees core memory pages into
      buddy allocator.  Because highmem pages are not freed by bootmem
      allocator, all highmem zones' present_pages becomes zero.
      
      Various options for improving the situation are being discussed but for
      now, let's return to the 3.6 code.
      
      Cc: Jianguo Wu <wujianguo@huawei.com>
      Cc: Jiang Liu <jiang.liu@huawei.com>
      Cc: Petr Tesarik <ptesarik@suse.cz>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Tested-by: default avatarChris Clayton <chris2553@googlemail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5576646f
    • Hugh Dickins's avatar
      tmpfs: change final i_blocks BUG to WARNING · 0f3c42f5
      Hugh Dickins authored
      Under a particular load on one machine, I have hit shmem_evict_inode()'s
      BUG_ON(inode->i_blocks), enough times to narrow it down to a particular
      race between swapout and eviction.
      
      It comes from the "if (freed > 0)" asymmetry in shmem_recalc_inode(),
      and the lack of coherent locking between mapping's nrpages and shmem's
      swapped count.  There's a window in shmem_writepage(), between lowering
      nrpages in shmem_delete_from_page_cache() and then raising swapped
      count, when the freed count appears to be +1 when it should be 0, and
      then the asymmetry stops it from being corrected with -1 before hitting
      the BUG.
      
      One answer is coherent locking: using tree_lock throughout, without
      info->lock; reasonable, but the raw_spin_lock in percpu_counter_add() on
      used_blocks makes that messier than expected.  Another answer may be a
      further effort to eliminate the weird shmem_recalc_inode() altogether,
      but previous attempts at that failed.
      
      So far undecided, but for now change the BUG_ON to WARN_ON: in usual
      circumstances it remains a useful consistency check.
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0f3c42f5
    • Hugh Dickins's avatar
      tmpfs: fix shmem_getpage_gfp() VM_BUG_ON · 215c02bc
      Hugh Dickins authored
      Fuzzing with trinity hit the "impossible" VM_BUG_ON(error) (which Fedora
      has converted to WARNING) in shmem_getpage_gfp():
      
        WARNING: at mm/shmem.c:1151 shmem_getpage_gfp+0xa5c/0xa70()
        Pid: 29795, comm: trinity-child4 Not tainted 3.7.0-rc2+ #49
        Call Trace:
          warn_slowpath_common+0x7f/0xc0
          warn_slowpath_null+0x1a/0x20
          shmem_getpage_gfp+0xa5c/0xa70
          shmem_fault+0x4f/0xa0
          __do_fault+0x71/0x5c0
          handle_pte_fault+0x97/0xae0
          handle_mm_fault+0x289/0x350
          __do_page_fault+0x18e/0x530
          do_page_fault+0x2b/0x50
          page_fault+0x28/0x30
          tracesys+0xe1/0xe6
      
      Thanks to Johannes for pointing to truncation: free_swap_and_cache()
      only does a trylock on the page, so the page lock we've held since
      before confirming swap is not enough to protect against truncation.
      
      What cleanup is needed in this case? Just delete_from_swap_cache(),
      which takes care of the memcg uncharge.
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Reported-by: default avatarDave Jones <davej@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      215c02bc
    • Will Deacon's avatar
      mm: highmem: don't treat PKMAP_ADDR(LAST_PKMAP) as a highmem address · 498c2280
      Will Deacon authored
      kmap_to_page returns the corresponding struct page for a virtual address
      of an arbitrary mapping.  This works by checking whether the address
      falls in the pkmap region and using the pkmap page tables instead of the
      linear mapping if appropriate.
      
      Unfortunately, the bounds checking means that PKMAP_ADDR(LAST_PKMAP) is
      incorrectly treated as a highmem address and we can end up walking off
      the end of pkmap_page_table and subsequently passing junk to pte_page.
      
      This patch fixes the bound check to stay within the pkmap tables.
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      498c2280
    • Mel Gorman's avatar
      mm: revert "mm: vmscan: scale number of pages reclaimed by reclaim/compaction based on failures" · 96710098
      Mel Gorman authored
      Jiri Slaby reported the following:
      
      	(It's an effective revert of "mm: vmscan: scale number of pages
      	reclaimed by reclaim/compaction based on failures".) Given kswapd
      	had hours of runtime in ps/top output yesterday in the morning
      	and after the revert it's now 2 minutes in sum for the last 24h,
      	I would say, it's gone.
      
      The intention of the patch in question was to compensate for the loss of
      lumpy reclaim.  Part of the reason lumpy reclaim worked is because it
      aggressively reclaimed pages and this patch was meant to be a sane
      compromise.
      
      When compaction fails, it gets deferred and both compaction and
      reclaim/compaction is deferred avoid excessive reclaim.  However, since
      commit c6543459 ("mm: remove __GFP_NO_KSWAPD"), kswapd is woken up
      each time and continues reclaiming which was not taken into account when
      the patch was developed.
      
      Attempts to address the problem ended up just changing the shape of the
      problem instead of fixing it.  The release window gets closer and while
      a THP allocation failing is not a major problem, kswapd chewing up a lot
      of CPU is.
      
      This patch reverts commit 83fde0f2 ("mm: vmscan: scale number of
      pages reclaimed by reclaim/compaction based on failures") and will be
      revisited in the future.
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Cc: Zdenek Kabelac <zkabelac@redhat.com>
      Tested-by: default avatarValdis Kletnieks <Valdis.Kletnieks@vt.edu>
      Cc: Jiri Slaby <jirislaby@gmail.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Jiri Slaby <jslaby@suse.cz>
      Cc: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      96710098
    • Randy Dunlap's avatar
      rapidio: fix kernel-doc warnings · 2ca3cb50
      Randy Dunlap authored
      Fix rapidio kernel-doc warnings:
      
        Warning(drivers/rapidio/rio.c:415): No description found for parameter 'local'
        Warning(drivers/rapidio/rio.c:415): Excess function parameter 'lstart' description in 'rio_map_inb_region'
        Warning(include/linux/rio.h:290): No description found for parameter 'switches'
        Warning(include/linux/rio.h:290): No description found for parameter 'destid_table'
      Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Cc: Matt Porter <mporter@kernel.crashing.org>
      Acked-by: default avatarAlexandre Bounine <alexandre.bounine@idt.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2ca3cb50
    • Xiaotian Feng's avatar
      swapfile: fix name leak in swapoff · f58b59c1
      Xiaotian Feng authored
      There's a name leak introduced by commit 91a27b2a ("vfs: define
      struct filename and have getname() return it").  Add the missing
      putname.
      
      [akpm@linux-foundation.org: cleanup]
      Signed-off-by: default avatarXiaotian Feng <dannyfeng@tencent.com>
      Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f58b59c1
    • Hugh Dickins's avatar
      memcg: fix hotplugged memory zone oops · bea8c150
      Hugh Dickins authored
      When MEMCG is configured on (even when it's disabled by boot option),
      when adding or removing a page to/from its lru list, the zone pointer
      used for stats updates is nowadays taken from the struct lruvec.  (On
      many configurations, calculating zone from page is slower.)
      
      But we have no code to update all the lruvecs (per zone, per memcg) when
      a memory node is hotadded.  Here's an extract from the oops which
      results when running numactl to bind a program to a newly onlined node:
      
        BUG: unable to handle kernel NULL pointer dereference at 0000000000000f60
        IP:  __mod_zone_page_state+0x9/0x60
        Pid: 1219, comm: numactl Not tainted 3.6.0-rc5+ #180 Bochs Bochs
        Process numactl (pid: 1219, threadinfo ffff880039abc000, task ffff8800383c4ce0)
        Call Trace:
          __pagevec_lru_add_fn+0xdf/0x140
          pagevec_lru_move_fn+0xb1/0x100
          __pagevec_lru_add+0x1c/0x30
          lru_add_drain_cpu+0xa3/0x130
          lru_add_drain+0x2f/0x40
         ...
      
      The natural solution might be to use a memcg callback whenever memory is
      hotadded; but that solution has not been scoped out, and it happens that
      we do have an easy location at which to update lruvec->zone.  The lruvec
      pointer is discovered either by mem_cgroup_zone_lruvec() or by
      mem_cgroup_page_lruvec(), and both of those do know the right zone.
      
      So check and set lruvec->zone in those; and remove the inadequate
      attempt to set lruvec->zone from lruvec_init(), which is called before
      NODE_DATA(node) has been allocated in such cases.
      
      Ah, there was one exceptionr.  For no particularly good reason,
      mem_cgroup_force_empty_list() has its own code for deciding lruvec.
      Change it to use the standard mem_cgroup_zone_lruvec() and
      mem_cgroup_get_lru_size() too.  In fact it was already safe against such
      an oops (the lru lists in danger could only be empty), but we're better
      proofed against future changes this way.
      
      I've marked this for stable (3.6) since we introduced the problem in 3.5
      (now closed to stable); but I have no idea if this is the only fix
      needed to get memory hotadd working with memcg in 3.6, and received no
      answer when I enquired twice before.
      Reported-by: default avatarTang Chen <tangchen@cn.fujitsu.com>
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
      Cc: Wen Congyang <wency@cn.fujitsu.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bea8c150
    • David Rientjes's avatar
      mips, arc: fix build failure · 18f69427
      David Rientjes authored
      Using a cross-compiler to fix another issue, the following build error
      occurred for mips defconfig:
      
        arch/mips/fw/arc/misc.c: In function 'ArcHalt':
        arch/mips/fw/arc/misc.c:25:2: error: implicit declaration of function 'local_irq_disable'
      
      Fix it up by including irqflags.h.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      18f69427
    • Michal Hocko's avatar
      memcg: oom: fix totalpages calculation for memory.swappiness==0 · 9a5a8f19
      Michal Hocko authored
      oom_badness() takes a totalpages argument which says how many pages are
      available and it uses it as a base for the score calculation.  The value
      is calculated by mem_cgroup_get_limit which considers both limit and
      total_swap_pages (resp.  memsw portion of it).
      
      This is usually correct but since fe35004f ("mm: avoid swapping out
      with swappiness==0") we do not swap when swappiness is 0 which means
      that we cannot really use up all the totalpages pages.  This in turn
      confuses oom score calculation if the memcg limit is much smaller than
      the available swap because the used memory (capped by the limit) is
      negligible comparing to totalpages so the resulting score is too small
      if adj!=0 (typically task with CAP_SYS_ADMIN or non zero oom_score_adj).
      A wrong process might be selected as result.
      
      The problem can be worked around by checking mem_cgroup_swappiness==0
      and not considering swap at all in such a case.
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.cz>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9a5a8f19
    • David Rientjes's avatar
      mm: fix build warning for uninitialized value · 1756954c
      David Rientjes authored
      do_wp_page() sets mmun_called if mmun_start and mmun_end were
      initialized and, if so, may call mmu_notifier_invalidate_range_end()
      with these values.  This doesn't prevent gcc from emitting a build
      warning though:
      
        mm/memory.c: In function `do_wp_page':
        mm/memory.c:2530: warning: `mmun_start' may be used uninitialized in this function
        mm/memory.c:2531: warning: `mmun_end' may be used uninitialized in this function
      
      It's much easier to initialize the variables to impossible values and do
      a simple comparison to determine if they were initialized to remove the
      bool entirely.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1756954c
    • Michel Lespinasse's avatar
      mm: add anon_vma_lock to validate_mm() · 63c3b902
      Michel Lespinasse authored
      Iterating over the vma->anon_vma_chain without anon_vma_lock may cause
      NULL ptr deref in anon_vma_interval_tree_verify(), because the node in the
      chain might have been removed.
      
        BUG: unable to handle kernel paging request at fffffffffffffff0
        IP: [<ffffffff8122c29c>] anon_vma_interval_tree_verify+0xc/0xa0
        PGD 4e28067 PUD 4e29067 PMD 0
        Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
        CPU 0
        Pid: 9050, comm: trinity-child64 Tainted: G        W    3.7.0-rc2-next-20121025-sasha-00001-g673f98e-dirty #77
        RIP: 0010: anon_vma_interval_tree_verify+0xc/0xa0
        Process trinity-child64 (pid: 9050, threadinfo ffff880045f80000, task ffff880048eb0000)
        Call Trace:
          validate_mm+0x58/0x1e0
          vma_adjust+0x635/0x6b0
          __split_vma.isra.22+0x161/0x220
          split_vma+0x24/0x30
          sys_madvise+0x5da/0x7b0
          tracesys+0xe1/0xe6
        RIP  anon_vma_interval_tree_verify+0xc/0xa0
        CR2: fffffffffffffff0
      
      Figured out by Bob Liu.
      Reported-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Cc: Bob Liu <lliubbo@gmail.com>
      Signed-off-by: default avatarMichel Lespinasse <walken@google.com>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      63c3b902
  2. 15 Nov, 2012 9 commits
  3. 14 Nov, 2012 6 commits
  4. 13 Nov, 2012 11 commits
  5. 12 Nov, 2012 2 commits
    • Petr Matousek's avatar
      KVM: x86: invalid opcode oops on SET_SREGS with OSXSAVE bit set (CVE-2012-4461) · 6d1068b3
      Petr Matousek authored
      On hosts without the XSAVE support unprivileged local user can trigger
      oops similar to the one below by setting X86_CR4_OSXSAVE bit in guest
      cr4 register using KVM_SET_SREGS ioctl and later issuing KVM_RUN
      ioctl.
      
      invalid opcode: 0000 [#2] SMP
      Modules linked in: tun ip6table_filter ip6_tables ebtable_nat ebtables
      ...
      Pid: 24935, comm: zoog_kvm_monito Tainted: G      D      3.2.0-3-686-pae
      EIP: 0060:[<f8b9550c>] EFLAGS: 00210246 CPU: 0
      EIP is at kvm_arch_vcpu_ioctl_run+0x92a/0xd13 [kvm]
      EAX: 00000001 EBX: 000f387e ECX: 00000000 EDX: 00000000
      ESI: 00000000 EDI: 00000000 EBP: ef5a0060 ESP: d7c63e70
       DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
      Process zoog_kvm_monito (pid: 24935, ti=d7c62000 task=ed84a0c0
      task.ti=d7c62000)
      Stack:
       00000001 f70a1200 f8b940a9 ef5a0060 00000000 00200202 f8769009 00000000
       ef5a0060 000f387e eda5c020 8722f9c8 00015bae 00000000 ed84a0c0 ed84a0c0
       c12bf02d 0000ae80 ef7f8740 fffffffb f359b740 ef5a0060 f8b85dc1 0000ae80
      Call Trace:
       [<f8b940a9>] ? kvm_arch_vcpu_ioctl_set_sregs+0x2fe/0x308 [kvm]
      ...
       [<c12bfb44>] ? syscall_call+0x7/0xb
      Code: 89 e8 e8 14 ee ff ff ba 00 00 04 00 89 e8 e8 98 48 ff ff 85 c0 74
      1e 83 7d 48 00 75 18 8b 85 08 07 00 00 31 c9 8b 95 0c 07 00 00 <0f> 01
      d1 c7 45 48 01 00 00 00 c7 45 1c 01 00 00 00 0f ae f0 89
      EIP: [<f8b9550c>] kvm_arch_vcpu_ioctl_run+0x92a/0xd13 [kvm] SS:ESP
      0068:d7c63e70
      
      QEMU first retrieves the supported features via KVM_GET_SUPPORTED_CPUID
      and then sets them later. So guest's X86_FEATURE_XSAVE should be masked
      out on hosts without X86_FEATURE_XSAVE, making kvm_set_cr4 with
      X86_CR4_OSXSAVE fail. Userspaces that allow specifying guest cpuid with
      X86_FEATURE_XSAVE even on hosts that do not support it, might be
      susceptible to this attack from inside the guest as well.
      
      Allow setting X86_CR4_OSXSAVE bit only if host has XSAVE support.
      Signed-off-by: default avatarPetr Matousek <pmatouse@redhat.com>
      Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
      6d1068b3
    • Ulf Hansson's avatar
      clk: ux500: Register slimbus clock lookups for u8500 · 3d930678
      Ulf Hansson authored
      At the same time the prcc bit for the kclk is corrected to
      bit 8 instead of 3.
      Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
      Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      Acked-by: default avatarLee Jones <lee.jones@linaro.org>
      Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
      3d930678