1. 07 Aug, 2015 6 commits
    • Amanieu d'Antras's avatar
      signal: fix information leak in copy_siginfo_from_user32 · 3c00cb5e
      Amanieu d'Antras authored
      This function can leak kernel stack data when the user siginfo_t has a
      positive si_code value.  The top 16 bits of si_code descibe which fields
      in the siginfo_t union are active, but they are treated inconsistently
      between copy_siginfo_from_user32, copy_siginfo_to_user32 and
      copy_siginfo_to_user.
      
      copy_siginfo_from_user32 is called from rt_sigqueueinfo and
      rt_tgsigqueueinfo in which the user has full control overthe top 16 bits
      of si_code.
      
      This fixes the following information leaks:
      x86:   8 bytes leaked when sending a signal from a 32-bit process to
             itself. This leak grows to 16 bytes if the process uses x32.
             (si_code = __SI_CHLD)
      x86:   100 bytes leaked when sending a signal from a 32-bit process to
             a 64-bit process. (si_code = -1)
      sparc: 4 bytes leaked when sending a signal from a 32-bit process to a
             64-bit process. (si_code = any)
      
      parsic and s390 have similar bugs, but they are not vulnerable because
      rt_[tg]sigqueueinfo have checks that prevent sending a positive si_code
      to a different process.  These bugs are also fixed for consistency.
      Signed-off-by: default avatarAmanieu d'Antras <amanieu@gmail.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3c00cb5e
    • Joseph Qi's avatar
      ocfs2: fix BUG in ocfs2_downconvert_thread_do_work() · 209f7512
      Joseph Qi authored
      The "BUG_ON(list_empty(&osb->blocked_lock_list))" in
      ocfs2_downconvert_thread_do_work can be triggered in the following case:
      
      ocfs2dc has firstly saved osb->blocked_lock_count to local varibale
      processed, and then processes the dentry lockres.  During the dentry
      put, it calls iput and then deletes rw, inode and open lockres from
      blocked list in ocfs2_mark_lockres_freeing.  And this causes the
      variable `processed' to not reflect the number of blocked lockres to be
      processed, which triggers the BUG.
      Signed-off-by: default avatarJoseph Qi <joseph.qi@huawei.com>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Cc: Joel Becker <jlbec@evilplan.org>
      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>
      209f7512
    • Mel Gorman's avatar
      fs, file table: reinit files_stat.max_files after deferred memory initialisation · 4248b0da
      Mel Gorman authored
      Dave Hansen reported the following;
      
      	My laptop has been behaving strangely with 4.2-rc2.  Once I log
      	in to my X session, I start getting all kinds of strange errors
      	from applications and see this in my dmesg:
      
              	VFS: file-max limit 8192 reached
      
      The problem is that the file-max is calculated before memory is fully
      initialised and miscalculates how much memory the kernel is using.  This
      patch recalculates file-max after deferred memory initialisation.  Note
      that using memory hotplug infrastructure would not have avoided this
      problem as the value is not recalculated after memory hot-add.
      
      4.1:             files_stat.max_files = 6582781
      4.2-rc2:         files_stat.max_files = 8192
      4.2-rc2 patched: files_stat.max_files = 6562467
      
      Small differences with the patch applied and 4.1 but not enough to matter.
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Reported-by: default avatarDave Hansen <dave.hansen@intel.com>
      Cc: Nicolai Stange <nicstange@gmail.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Alex Ng <alexng@microsoft.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4248b0da
    • Nicolai Stange's avatar
      mm, meminit: replace rwsem with completion · d3cd131d
      Nicolai Stange authored
      Commit 0e1cc95b ("mm: meminit: finish initialisation of struct pages
      before basic setup") introduced a rwsem to signal completion of the
      initialization workers.
      
      Lockdep complains about possible recursive locking:
        =============================================
        [ INFO: possible recursive locking detected ]
        4.1.0-12802-g1dc51b82 #3 Not tainted
        ---------------------------------------------
        swapper/0/1 is trying to acquire lock:
        (pgdat_init_rwsem){++++.+},
          at: [<ffffffff8424c7fb>] page_alloc_init_late+0xc7/0xe6
      
        but task is already holding lock:
        (pgdat_init_rwsem){++++.+},
          at: [<ffffffff8424c772>] page_alloc_init_late+0x3e/0xe6
      
      Replace the rwsem by a completion together with an atomic
      "outstanding work counter".
      
      [peterz@infradead.org: Barrier removal on the grounds of being pointless]
      [mgorman@suse.de: Applied review feedback]
      Signed-off-by: default avatarNicolai Stange <nicstange@gmail.com>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Alex Ng <alexng@microsoft.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d3cd131d
    • Mel Gorman's avatar
      mm, meminit: allow early_pfn_to_nid to be used during runtime · 7ace9917
      Mel Gorman authored
      early_pfn_to_nid() historically was inherently not SMP safe but only
      used during boot which is inherently single threaded or during hotplug
      which is protected by a giant mutex.
      
      With deferred memory initialisation there was a thread-safe version
      introduced and the early_pfn_to_nid would trigger a BUG_ON if used
      unsafely.  Memory hotplug hit that check.  This patch makes
      early_pfn_to_nid introduces a lock to make it safe to use during
      hotplug.
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Reported-by: default avatarAlex Ng <alexng@microsoft.com>
      Tested-by: default avatarAlex Ng <alexng@microsoft.com>
      Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Nicolai Stange <nicstange@gmail.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7ace9917
    • Marcus Gelderie's avatar
      ipc: modify message queue accounting to not take kernel data structures into account · de54b9ac
      Marcus Gelderie authored
      A while back, the message queue implementation in the kernel was
      improved to use btrees to speed up retrieval of messages, in commit
      d6629859 ("ipc/mqueue: improve performance of send/recv").
      
      That patch introducing the improved kernel handling of message queues
      (using btrees) has, as a by-product, changed the meaning of the QSIZE
      field in the pseudo-file created for the queue.  Before, this field
      reflected the size of the user-data in the queue.  Since, it also takes
      kernel data structures into account.  For example, if 13 bytes of user
      data are in the queue, on my machine the file reports a size of 61
      bytes.
      
      There was some discussion on this topic before (for example
      https://lkml.org/lkml/2014/10/1/115).  Commenting on a th lkml, Michael
      Kerrisk gave the following background
      (https://lkml.org/lkml/2015/6/16/74):
      
          The pseudofiles in the mqueue filesystem (usually mounted at
          /dev/mqueue) expose fields with metadata describing a message
          queue. One of these fields, QSIZE, as originally implemented,
          showed the total number of bytes of user data in all messages in
          the message queue, and this feature was documented from the
          beginning in the mq_overview(7) page. In 3.5, some other (useful)
          work happened to break the user-space API in a couple of places,
          including the value exposed via QSIZE, which now includes a measure
          of kernel overhead bytes for the queue, a figure that renders QSIZE
          useless for its original purpose, since there's no way to deduce
          the number of overhead bytes consumed by the implementation.
          (The other user-space breakage was subsequently fixed.)
      
      This patch removes the accounting of kernel data structures in the
      queue.  Reporting the size of these data-structures in the QSIZE field
      was a breaking change (see Michael's comment above).  Without the QSIZE
      field reporting the total size of user-data in the queue, there is no
      way to deduce this number.
      
      It should be noted that the resource limit RLIMIT_MSGQUEUE is counted
      against the worst-case size of the queue (in both the old and the new
      implementation).  Therefore, the kernel overhead accounting in QSIZE is
      not necessary to help the user understand the limitations RLIMIT imposes
      on the processes.
      Signed-off-by: default avatarMarcus Gelderie <redmnic@gmail.com>
      Acked-by: default avatarDoug Ledford <dledford@redhat.com>
      Acked-by: default avatarMichael Kerrisk <mtk.manpages@gmail.com>
      Acked-by: default avatarDavidlohr Bueso <dbueso@suse.de>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: John Duffy <jb_duffy@btinternet.com>
      Cc: Arto Bendiken <arto@bendiken.net>
      Cc: Manfred Spraul <manfred@colorfullife.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>
      de54b9ac
  2. 05 Aug, 2015 5 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 4469942b
      Linus Torvalds authored
      Pull KVM fixes from Paolo Bonzini:
       "Just two very small & simple patches"
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
        KVM: MTRR: Use default type for non-MTRR-covered gfn before WARN_ON
        KVM: s390: Fix hang VCPU hang/loop regression
      4469942b
    • Alex Williamson's avatar
      KVM: MTRR: Use default type for non-MTRR-covered gfn before WARN_ON · fc1a8126
      Alex Williamson authored
      The patch was munged on commit to re-order these tests resulting in
      excessive warnings when trying to do device assignment.  Return to
      original ordering: https://lkml.org/lkml/2015/7/15/769
      
      Fixes: 3e5d2fdc ("KVM: MTRR: simplify kvm_mtrr_get_guest_memory_type")
      Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
      Reviewed-by: default avatarXiao Guangrong <guangrong.xiao@linux.intel.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      fc1a8126
    • Linus Torvalds's avatar
      Merge tag 'md/4.2-rc5-fixes' of git://neil.brown.name/md · 4e6b6ee2
      Linus Torvalds authored
      Pull md fixes from Neil Brown:
       "Three more fixes for md in 4.2
      
        Mostly corner-case stuff.
      
        One of these patches is for a CVE: CVE-2015-5697
      
        I'm not convinced it is serious (data leak from CAP_SYS_ADMIN ioctl)
        but as people seem to want to back-port it, I've included a minimal
        version here.  The remainder of that patch from Benjamin is
        code-cleanup and will arrive in the 4.3 merge window"
      
      * tag 'md/4.2-rc5-fixes' of git://neil.brown.name/md:
        md/raid5: don't let shrink_slab shrink too far.
        md: use kzalloc() when bitmap is disabled
        md/raid1: extend spinlock to protect raid1_end_read_request against inconsistencies
      4e6b6ee2
    • Linus Torvalds's avatar
      Merge branch 'for-4.2' of git://linux-nfs.org/~bfields/linux · 9e91edcd
      Linus Torvalds authored
      Pull nfsd fixes from Bruce Fields.
      
      * 'for-4.2' of git://linux-nfs.org/~bfields/linux:
        nfsd: do nfs4_check_fh in nfs4_check_file instead of nfs4_check_olstateid
        nfsd: Fix a file leak on nfsd4_layout_setlease failure
        nfsd: Drop BUG_ON and ignore SECLABEL on absent filesystem
      9e91edcd
    • Michal Hocko's avatar
      mm, vmscan: Do not wait for page writeback for GFP_NOFS allocations · ecf5fc6e
      Michal Hocko authored
      Nikolay has reported a hang when a memcg reclaim got stuck with the
      following backtrace:
      
      PID: 18308  TASK: ffff883d7c9b0a30  CPU: 1   COMMAND: "rsync"
        #0 __schedule at ffffffff815ab152
        #1 schedule at ffffffff815ab76e
        #2 schedule_timeout at ffffffff815ae5e5
        #3 io_schedule_timeout at ffffffff815aad6a
        #4 bit_wait_io at ffffffff815abfc6
        #5 __wait_on_bit at ffffffff815abda5
        #6 wait_on_page_bit at ffffffff8111fd4f
        #7 shrink_page_list at ffffffff81135445
        #8 shrink_inactive_list at ffffffff81135845
        #9 shrink_lruvec at ffffffff81135ead
       #10 shrink_zone at ffffffff811360c3
       #11 shrink_zones at ffffffff81136eff
       #12 do_try_to_free_pages at ffffffff8113712f
       #13 try_to_free_mem_cgroup_pages at ffffffff811372be
       #14 try_charge at ffffffff81189423
       #15 mem_cgroup_try_charge at ffffffff8118c6f5
       #16 __add_to_page_cache_locked at ffffffff8112137d
       #17 add_to_page_cache_lru at ffffffff81121618
       #18 pagecache_get_page at ffffffff8112170b
       #19 grow_dev_page at ffffffff811c8297
       #20 __getblk_slow at ffffffff811c91d6
       #21 __getblk_gfp at ffffffff811c92c1
       #22 ext4_ext_grow_indepth at ffffffff8124565c
       #23 ext4_ext_create_new_leaf at ffffffff81246ca8
       #24 ext4_ext_insert_extent at ffffffff81246f09
       #25 ext4_ext_map_blocks at ffffffff8124a848
       #26 ext4_map_blocks at ffffffff8121a5b7
       #27 mpage_map_one_extent at ffffffff8121b1fa
       #28 mpage_map_and_submit_extent at ffffffff8121f07b
       #29 ext4_writepages at ffffffff8121f6d5
       #30 do_writepages at ffffffff8112c490
       #31 __filemap_fdatawrite_range at ffffffff81120199
       #32 filemap_flush at ffffffff8112041c
       #33 ext4_alloc_da_blocks at ffffffff81219da1
       #34 ext4_rename at ffffffff81229b91
       #35 ext4_rename2 at ffffffff81229e32
       #36 vfs_rename at ffffffff811a08a5
       #37 SYSC_renameat2 at ffffffff811a3ffc
       #38 sys_renameat2 at ffffffff811a408e
       #39 sys_rename at ffffffff8119e51e
       #40 system_call_fastpath at ffffffff815afa89
      
      Dave Chinner has properly pointed out that this is a deadlock in the
      reclaim code because ext4 doesn't submit pages which are marked by
      PG_writeback right away.
      
      The heuristic was introduced by commit e62e384e ("memcg: prevent OOM
      with too many dirty pages") and it was applied only when may_enter_fs
      was specified.  The code has been changed by c3b94f44 ("memcg:
      further prevent OOM with too many dirty pages") which has removed the
      __GFP_FS restriction with a reasoning that we do not get into the fs
      code.  But this is not sufficient apparently because the fs doesn't
      necessarily submit pages marked PG_writeback for IO right away.
      
      ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily
      submit the bio.  Instead it tries to map more pages into the bio and
      mpage_map_one_extent might trigger memcg charge which might end up
      waiting on a page which is marked PG_writeback but hasn't been submitted
      yet so we would end up waiting for something that never finishes.
      
      Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2)
      before we go to wait on the writeback.  The page fault path, which is
      the only path that triggers memcg oom killer since 3.12, shouldn't
      require GFP_NOFS and so we shouldn't reintroduce the premature OOM
      killer issue which was originally addressed by the heuristic.
      
      As per David Chinner the xfs is doing similar thing since 2.6.15 already
      so ext4 is not the only affected filesystem.  Moreover he notes:
      
      : For example: IO completion might require unwritten extent conversion
      : which executes filesystem transactions and GFP_NOFS allocations. The
      : writeback flag on the pages can not be cleared until unwritten
      : extent conversion completes. Hence memory reclaim cannot wait on
      : page writeback to complete in GFP_NOFS context because it is not
      : safe to do so, memcg reclaim or otherwise.
      
      Cc: stable@vger.kernel.org # 3.9+
      [tytso@mit.edu: corrected the control flow]
      Fixes: c3b94f44 ("memcg: further prevent OOM with too many dirty pages")
      Reported-by: default avatarNikolay Borisov <kernel@kyup.com>
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ecf5fc6e
  3. 04 Aug, 2015 9 commits
  4. 03 Aug, 2015 11 commits
  5. 02 Aug, 2015 5 commits
    • Linus Torvalds's avatar
      i915: temporary fix for DP MST docking station NULL pointer dereference · 27667f47
      Linus Torvalds authored
      Ted Ts'o reports that his Lenovo T540p ThinkPad crashes at boot if
      attached to the docking station.  This is a regression that he was able
      to bisect to commit 8c7b5ccb: "drm/i915: Use atomic helpers for
      computing changed flags:"
      
      The reason seems to be the new call to drm_atomic_helper_check_modeset()
      added to intel_modeset_compute_config(), which in turn calls
      update_connector_routing(), and somehow ends up picking a NULL crtc for
      the connector state, causing the subsequent drm_crtc_index() to OOPS.
      
      Daniel Vetter says that the fundamental issue seems to be confusion in
      the encoder selection, and this isn't the right fix, but while he chases
      down the proper fix, this at least avoids the NULL pointer dereference
      and makes Ted's docking station work again.
      Reported-bisected-and-tested-by: default avatarTheodore Ts'o <tytso@mit.edu>
      Cc: Daniel Vetter <daniel.vetter@intel.com>
      Cc: Mani Nikula <jani.nikula@linux.intel.com>
      Cc: Dave Airlie <airlied@gmail.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      27667f47
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · d4edea40
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "A set of three fixes for the ipr driver and one fairly major one for
        memory leaks in the mq path of SCSI"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: fix memory leak with scsi-mq
        ipr: Fix invalid array indexing for HRRQ
        ipr: Fix incorrect trace indexing
        ipr: Fix locking for unit attention handling
      d4edea40
    • Linus Torvalds's avatar
      Merge tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc · 30c7b56d
      Linus Torvalds authored
      Pull ARM SoC fixes from Olof Johansson:
       "Things are calming down nicely here w.r.t. fixes.  This batch
        includes two week's worth since I missed to send before -rc4.
      
        Nothing particularly scary to point out, smaller fixes here and there.
        Shortlog describes it pretty well"
      
      * tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
        ARM: dts: keystone: fix dt bindings to use post div register for mainpll
        ARM: nomadik: disable UART0 on Nomadik boards
        ARM: dts: i.MX35: Fix can support.
        ARM: OMAP2+: hwmod: Fix _wait_target_ready() for hwmods without sysc
        ARM: dts: add CPU OPP and regulator supply property for exynos4210
        ARM: dts: Update video-phy node with syscon phandle for exynos3250
        ARM: DRA7: hwmod: fix gpmc hwmod
      30c7b56d
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 01183609
      Linus Torvalds authored
      Pull VFS fix from Al Viro:
       "Spurious ENOTDIR fix"
      
      This should fix the problems reported by Dominique Martinet and Hugh
      Dickins.
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        link_path_walk(): be careful when failing with ENOTDIR
      01183609
    • Al Viro's avatar
      link_path_walk(): be careful when failing with ENOTDIR · 97242f99
      Al Viro authored
      In RCU mode we might end up with dentry evicted just we check
      that it's a directory.  In such case we should return ECHILD
      rather than ENOTDIR, so that pathwalk would be retries in non-RCU
      mode.
      
      Breakage had been introduced in commit b18825a7 - prior to that
      we were looking at nd->inode, which had been fetched before
      verifying that ->d_seq was still valid.  That form of check
      would only be satisfied if at some point the pathname prefix
      would indeed have resolved to a non-directory.  The fix consists
      of checking ->d_seq after we'd run into a non-directory dentry,
      and failing with ECHILD in case of mismatch.
      
      Note that all branches since 3.12 have that problem...
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      97242f99
  6. 01 Aug, 2015 4 commits