1. 18 Mar, 2015 38 commits
  2. 06 Mar, 2015 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 3.10.71 · 389fb5fb
      Greg Kroah-Hartman authored
      389fb5fb
    • Ilya Dryomov's avatar
      libceph: fix double __remove_osd() problem · 6af167fb
      Ilya Dryomov authored
      commit 7eb71e03 upstream.
      
      It turns out it's possible to get __remove_osd() called twice on the
      same OSD.  That doesn't sit well with rb_erase() - depending on the
      shape of the tree we can get a NULL dereference, a soft lockup or
      a random crash at some point in the future as we end up touching freed
      memory.  One scenario that I was able to reproduce is as follows:
      
                  <osd3 is idle, on the osd lru list>
      <con reset - osd3>
      con_fault_finish()
        osd_reset()
                                    <osdmap - osd3 down>
                                    ceph_osdc_handle_map()
                                      <takes map_sem>
                                      kick_requests()
                                        <takes request_mutex>
                                        reset_changed_osds()
                                          __reset_osd()
                                            __remove_osd()
                                        <releases request_mutex>
                                      <releases map_sem>
          <takes map_sem>
          <takes request_mutex>
          __kick_osd_requests()
            __reset_osd()
              __remove_osd() <-- !!!
      
      A case can be made that osd refcounting is imperfect and reworking it
      would be a proper resolution, but for now Sage and I decided to fix
      this by adding a safe guard around __remove_osd().
      
      Fixes: http://tracker.ceph.com/issues/8087
      
      Cc: Sage Weil <sage@redhat.com>
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      Reviewed-by: default avatarSage Weil <sage@redhat.com>
      Reviewed-by: default avatarAlex Elder <elder@linaro.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6af167fb