1. 25 Jan, 2016 36 commits
  2. 18 Jan, 2016 4 commits
    • Naoya Horiguchi's avatar
      mm: hugetlb: fix hugepage memory leak caused by wrong reserve count · 60d786c5
      Naoya Horiguchi authored
      commit a88c7695 upstream.
      
      When dequeue_huge_page_vma() in alloc_huge_page() fails, we fall back on
      alloc_buddy_huge_page() to directly create a hugepage from the buddy
      allocator.
      
      In that case, however, if alloc_buddy_huge_page() succeeds we don't
      decrement h->resv_huge_pages, which means that successful
      hugetlb_fault() returns without releasing the reserve count.  As a
      result, subsequent hugetlb_fault() might fail despite that there are
      still free hugepages.
      
      This patch simply adds decrementing code on that code path.
      
      I reproduced this problem when testing v4.3 kernel in the following situation:
       - the test machine/VM is a NUMA system,
       - hugepage overcommiting is enabled,
       - most of hugepages are allocated and there's only one free hugepage
         which is on node 0 (for example),
       - another program, which calls set_mempolicy(MPOL_BIND) to bind itself to
         node 1, tries to allocate a hugepage,
       - the allocation should fail but the reserve count is still hold.
      Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
      Cc: Mike Kravetz <mike.kravetz@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      [ luis: backported to 3.16:
        - use 'chg' instead of 'gbl_chg'
        - adjusted context ]
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      60d786c5
    • Mikulas Patocka's avatar
      parisc iommu: fix panic due to trying to allocate too large region · 03dd7ad3
      Mikulas Patocka authored
      commit e46e31a3 upstream.
      
      When using the Promise TX2+ SATA controller on PA-RISC, the system often
      crashes with kernel panic, for example just writing data with the dd
      utility will make it crash.
      
      Kernel panic - not syncing: drivers/parisc/sba_iommu.c: I/O MMU @ 000000000000a000 is out of mapping resources
      
      CPU: 0 PID: 18442 Comm: mkspadfs Not tainted 4.4.0-rc2 #2
      Backtrace:
       [<000000004021497c>] show_stack+0x14/0x20
       [<0000000040410bf0>] dump_stack+0x88/0x100
       [<000000004023978c>] panic+0x124/0x360
       [<0000000040452c18>] sba_alloc_range+0x698/0x6a0
       [<0000000040453150>] sba_map_sg+0x260/0x5b8
       [<000000000c18dbb4>] ata_qc_issue+0x264/0x4a8 [libata]
       [<000000000c19535c>] ata_scsi_translate+0xe4/0x220 [libata]
       [<000000000c19a93c>] ata_scsi_queuecmd+0xbc/0x320 [libata]
       [<0000000040499bbc>] scsi_dispatch_cmd+0xfc/0x130
       [<000000004049da34>] scsi_request_fn+0x6e4/0x970
       [<00000000403e95a8>] __blk_run_queue+0x40/0x60
       [<00000000403e9d8c>] blk_run_queue+0x3c/0x68
       [<000000004049a534>] scsi_run_queue+0x2a4/0x360
       [<000000004049be68>] scsi_end_request+0x1a8/0x238
       [<000000004049de84>] scsi_io_completion+0xfc/0x688
       [<0000000040493c74>] scsi_finish_command+0x17c/0x1d0
      
      The cause of the crash is not exhaustion of the IOMMU space, there is
      plenty of free pages. The function sba_alloc_range is called with size
      0x11000, thus the pages_needed variable is 0x11. The function
      sba_search_bitmap is called with bits_wanted 0x11 and boundary size is
      0x10 (because dma_get_seg_boundary(dev) returns 0xffff).
      
      The function sba_search_bitmap attempts to allocate 17 pages that must not
      cross 16-page boundary - it can't satisfy this requirement
      (iommu_is_span_boundary always returns true) and fails even if there are
      many free entries in the IOMMU space.
      
      How did it happen that we try to allocate 17 pages that don't cross
      16-page boundary? The cause is in the function iommu_coalesce_chunks. This
      function tries to coalesce adjacent entries in the scatterlist. The
      function does several checks if it may coalesce one entry with the next,
      one of those checks is this:
      
      	if (startsg->length + dma_len > max_seg_size)
      		break;
      
      When it finishes coalescing adjacent entries, it allocates the mapping:
      
      sg_dma_len(contig_sg) = dma_len;
      dma_len = ALIGN(dma_len + dma_offset, IOVP_SIZE);
      sg_dma_address(contig_sg) =
      	PIDE_FLAG
      	| (iommu_alloc_range(ioc, dev, dma_len) << IOVP_SHIFT)
      	| dma_offset;
      
      It is possible that (startsg->length + dma_len > max_seg_size) is false
      (we are just near the 0x10000 max_seg_size boundary), so the funcion
      decides to coalesce this entry with the next entry. When the coalescing
      succeeds, the function performs
      	dma_len = ALIGN(dma_len + dma_offset, IOVP_SIZE);
      And now, because of non-zero dma_offset, dma_len is greater than 0x10000.
      iommu_alloc_range (a pointer to sba_alloc_range) is called and it attempts
      to allocate 17 pages for a device that must not cross 16-page boundary.
      
      To fix the bug, we must make sure that dma_len after addition of
      dma_offset and alignment doesn't cross the segment boundary. I.e. change
      	if (startsg->length + dma_len > max_seg_size)
      		break;
      to
      	if (ALIGN(dma_len + dma_offset + startsg->length, IOVP_SIZE) > max_seg_size)
      		break;
      
      This patch makes this change (it precalculates max_seg_boundary at the
      beginning of the function iommu_coalesce_chunks). I also added a check
      that the mapping length doesn't exceed dma_get_seg_boundary(dev) (it is
      not needed for Promise TX2+ SATA, but it may be needed for other devices
      that have dma_get_seg_boundary lower than dma_get_max_seg_size).
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      03dd7ad3
    • Alan Stern's avatar
      USB: add quirk for devices with broken LPM · 23b42ce5
      Alan Stern authored
      commit ad87e032 upstream.
      
      Some USB device / host controller combinations seem to have problems
      with Link Power Management.  For example, Steinar found that his xHCI
      controller wouldn't handle bandwidth calculations correctly for two
      video cards simultaneously when LPM was enabled, even though the bus
      had plenty of bandwidth available.
      
      This patch introduces a new quirk flag for devices that should remain
      disabled for LPM, and creates quirk entries for Steinar's devices.
      Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
      Reported-by: default avatarSteinar H. Gunderson <sgunderson@bigfoot.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      [ luis: backported to 3.16: adjusted context ]
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      23b42ce5
    • Mathias Nyman's avatar
      xhci: fix usb2 resume timing and races. · 30f8b511
      Mathias Nyman authored
      commit f69115fd upstream.
      
      According to USB 2 specs ports need to signal resume for at least 20ms,
      in practice even longer, before moving to U0 state.
      Both host and devices can initiate resume.
      
      On device initiated resume, a port status interrupt with the port in resume
      state in issued. The interrupt handler tags a resume_done[port]
      timestamp with current time + USB_RESUME_TIMEOUT, and kick roothub timer.
      Root hub timer requests for port status, finds the port in resume state,
      checks if resume_done[port] timestamp passed, and set port to U0 state.
      
      On host initiated resume, current code sets the port to resume state,
      sleep 20ms, and finally sets the port to U0 state. This should also
      be changed to work in a similar way as the device initiated resume, with
      timestamp tagging, but that is not yet tested and will be a separate
      fix later.
      
      There are a few issues with this approach
      
      1. A host initiated resume will also generate a resume event. The event
         handler will find the port in resume state, believe it's a device
         initiated resume, and act accordingly.
      
      2. A port status request might cut the resume signalling short if a
         get_port_status request is handled during the host resume signalling.
         The port will be found in resume state. The timestamp is not set leading
         to time_after_eq(jiffies, timestamp) returning true, as timestamp = 0.
         get_port_status will proceed with moving the port to U0.
      
      3. If an error, or anything else happens to the port during device
         initiated resume signalling it will leave all the device resume
         parameters hanging uncleared, preventing further suspend, returning
         -EBUSY, and cause the pm thread to busyloop trying to enter suspend.
      
      Fix this by using the existing resuming_ports bitfield to indicate that
      resume signalling timing is taken care of.
      Check if the resume_done[port] is set before using it for timestamp
      comparison, and also clear out any resume signalling related variables
      if port is not in U0 or Resume state
      
      This issue was discovered when a PM thread busylooped, trying to runtime
      suspend the xhci USB 2 roothub on a Dell XPS
      Reported-by: default avatarDaniel J Blueman <daniel@quora.org>
      Tested-by: default avatarDaniel J Blueman <daniel@quora.org>
      Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      30f8b511