1. 09 Mar, 2016 3 commits
  2. 08 Mar, 2016 33 commits
  3. 04 Mar, 2016 4 commits
    • Simon Guinot's avatar
      kernel/resource.c: fix muxed resource handling in __request_region() · c40374d5
      Simon Guinot authored
      commit 59ceeaaf upstream.
      
      In __request_region, if a conflict with a BUSY and MUXED resource is
      detected, then the caller goes to sleep and waits for the resource to be
      released.  A pointer on the conflicting resource is kept.  At wake-up
      this pointer is used as a parent to retry to request the region.
      
      A first problem is that this pointer might well be invalid (if for
      example the conflicting resource have already been freed).  Another
      problem is that the next call to __request_region() fails to detect a
      remaining conflict.  The previously conflicting resource is passed as a
      parameter and __request_region() will look for a conflict among the
      children of this resource and not at the resource itself.  It is likely
      to succeed anyway, even if there is still a conflict.
      
      Instead, the parent of the conflicting resource should be passed to
      __request_region().
      
      As a fix, this patch doesn't update the parent resource pointer in the
      case we have to wait for a muxed region right after.
      Reported-and-tested-by: default avatarVincent Pelletier <plr.vincent@gmail.com>
      Signed-off-by: default avatarSimon Guinot <simon.guinot@sequanux.org>
      Tested-by: default avatarVincent Donnefort <vdonnefort@gmail.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      c40374d5
    • Jan Kara's avatar
      ext4: fix crashes in dioread_nolock mode · c0c009a0
      Jan Kara authored
      commit 74dae427 upstream.
      
      Competing overwrite DIO in dioread_nolock mode will just overwrite
      pointer to io_end in the inode. This may result in data corruption or
      extent conversion happening from IO completion interrupt because we
      don't properly set buffer_defer_completion() when unlocked DIO races
      with locked DIO to unwritten extent.
      
      Since unlocked DIO doesn't need io_end for anything, just avoid
      allocating it and corrupting pointer from inode for locked DIO.
      A cleaner fix would be to avoid these games with io_end pointer from the
      inode but that requires more intrusive changes so we leave that for
      later.
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      c0c009a0
    • Jan Kara's avatar
      ext4: fix bh->b_state corruption · 6d4048ac
      Jan Kara authored
      commit ed8ad838 upstream.
      
      ext4 can update bh->b_state non-atomically in _ext4_get_block() and
      ext4_da_get_block_prep(). Usually this is fine since bh is just a
      temporary storage for mapping information on stack but in some cases it
      can be fully living bh attached to a page. In such case non-atomic
      update of bh->b_state can race with an atomic update which then gets
      lost. Usually when we are mapping bh and thus updating bh->b_state
      non-atomically, nobody else touches the bh and so things work out fine
      but there is one case to especially worry about: ext4_finish_bio() uses
      BH_Uptodate_Lock on the first bh in the page to synchronize handling of
      PageWriteback state. So when blocksize < pagesize, we can be atomically
      modifying bh->b_state of a buffer that actually isn't under IO and thus
      can race e.g. with delalloc trying to map that buffer. The result is
      that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
      corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.
      
      Fix the problem by always updating bh->b_state bits atomically.
      Reported-by: default avatarNikolay Borisov <kernel@kyup.com>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      [ luis: backported to 3.16:
        - replaced READ_ONCE() by ACCESS_ONCE() ]
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      6d4048ac
    • Gerd Hoffmann's avatar
      drm/qxl: use kmalloc_array to alloc reloc_info in qxl_process_single_command · 14aa81c8
      Gerd Hoffmann authored
      commit 34855706 upstream.
      
      This avoids integer overflows on 32bit machines when calculating
      reloc_info size, as reported by Alan Cox.
      
      Cc: gnomes@lxorguk.ukuu.org.uk
      Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      14aa81c8