1. 12 Jul, 2012 1 commit
    • Eric Dumazet's avatar
      splice: fix racy pipe->buffers uses · 9558b2ab
      Eric Dumazet authored
      commit 047fe360 upstream.
      
      Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
      by splice_shrink_spd() called from vmsplice_to_pipe()
      
      commit 35f3d14d (pipe: add support for shrinking and growing pipes)
      added capability to adjust pipe->buffers.
      
      Problem is some paths don't hold pipe mutex and assume pipe->buffers
      doesn't change for their duration.
      
      Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
      use it in place of pipe->buffers where appropriate.
      
      splice_shrink_spd() loses its struct pipe_inode_info argument.
      Reported-by: default avatarDave Jones <davej@redhat.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Tom Herbert <therbert@google.com>
      Tested-by: default avatarDave Jones <davej@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      [bwh: Backported to 3.2:
       - Adjust context in vmsplice_to_pipe()
       - Update one more call to splice_shrink_spd(), from skb_splice_bits()]
      Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      9558b2ab
  2. 04 Jul, 2012 39 commits