1. 21 4月, 2017 26 次提交
  2. 20 4月, 2017 2 次提交
  3. 19 4月, 2017 1 次提交
  4. 18 4月, 2017 4 次提交
    • P
      Merge remote-tracking branch 'remotes/famz/tags/block-pull-request' into staging · d1263f8f
      Peter Maydell 提交于
      # gpg: Signature made Tue 18 Apr 2017 15:58:32 BST
      # gpg:                using RSA key 0xCA35624C6A9171C6
      # gpg: Good signature from "Fam Zheng <famz@redhat.com>"
      # gpg: WARNING: This key is not certified with sufficiently trusted signatures!
      # gpg:          It is not certain that the signature belongs to the owner.
      # Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6
      
      * remotes/famz/tags/block-pull-request:
        block: Drain BH in bdrv_drained_begin
        block: Walk bs->children carefully in bdrv_drain_recurse
      Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
      d1263f8f
    • F
      block: Drain BH in bdrv_drained_begin · 91af091f
      Fam Zheng 提交于
      During block job completion, nothing is preventing
      block_job_defer_to_main_loop_bh from being called in a nested
      aio_poll(), which is a trouble, such as in this code path:
      
          qmp_block_commit
            commit_active_start
              bdrv_reopen
                bdrv_reopen_multiple
                  bdrv_reopen_prepare
                    bdrv_flush
                      aio_poll
                        aio_bh_poll
                          aio_bh_call
                            block_job_defer_to_main_loop_bh
                              stream_complete
                                bdrv_reopen
      
      block_job_defer_to_main_loop_bh is the last step of the stream job,
      which should have been "paused" by the bdrv_drained_begin/end in
      bdrv_reopen_multiple, but it is not done because it's in the form of a
      main loop BH.
      
      Similar to why block jobs should be paused between drained_begin and
      drained_end, BHs they schedule must be excluded as well.  To achieve
      this, this patch forces draining the BH in BDRV_POLL_WHILE.
      
      As a side effect this fixes a hang in block_job_detach_aio_context
      during system_reset when a block job is ready:
      
          #0  0x0000555555aa79f3 in bdrv_drain_recurse
          #1  0x0000555555aa825d in bdrv_drained_begin
          #2  0x0000555555aa8449 in bdrv_drain
          #3  0x0000555555a9c356 in blk_drain
          #4  0x0000555555aa3cfd in mirror_drain
          #5  0x0000555555a66e11 in block_job_detach_aio_context
          #6  0x0000555555a62f4d in bdrv_detach_aio_context
          #7  0x0000555555a63116 in bdrv_set_aio_context
          #8  0x0000555555a9d326 in blk_set_aio_context
          #9  0x00005555557e38da in virtio_blk_data_plane_stop
          #10 0x00005555559f9d5f in virtio_bus_stop_ioeventfd
          #11 0x00005555559fa49b in virtio_bus_stop_ioeventfd
          #12 0x00005555559f6a18 in virtio_pci_stop_ioeventfd
          #13 0x00005555559f6a18 in virtio_pci_reset
          #14 0x00005555559139a9 in qdev_reset_one
          #15 0x0000555555916738 in qbus_walk_children
          #16 0x0000555555913318 in qdev_walk_children
          #17 0x0000555555916738 in qbus_walk_children
          #18 0x00005555559168ca in qemu_devices_reset
          #19 0x000055555581fcbb in pc_machine_reset
          #20 0x00005555558a4d96 in qemu_system_reset
          #21 0x000055555577157a in main_loop_should_exit
          #22 0x000055555577157a in main_loop
          #23 0x000055555577157a in main
      
      The rationale is that the loop in block_job_detach_aio_context cannot
      make any progress in pausing/completing the job, because bs->in_flight
      is 0, so bdrv_drain doesn't process the block_job_defer_to_main_loop
      BH. With this patch, it does.
      Reported-by: NJeff Cody <jcody@redhat.com>
      Signed-off-by: NFam Zheng <famz@redhat.com>
      Message-Id: <20170418143044.12187-3-famz@redhat.com>
      Reviewed-by: NJeff Cody <jcody@redhat.com>
      Tested-by: NJeff Cody <jcody@redhat.com>
      Signed-off-by: NFam Zheng <famz@redhat.com>
      91af091f
    • F
      block: Walk bs->children carefully in bdrv_drain_recurse · 178bd438
      Fam Zheng 提交于
      The recursive bdrv_drain_recurse may run a block job completion BH that
      drops nodes. The coming changes will make that more likely and use-after-free
      would happen without this patch
      
      Stash the bs pointer and use bdrv_ref/bdrv_unref in addition to
      QLIST_FOREACH_SAFE to prevent such a case from happening.
      
      Since bdrv_unref accesses global state that is not protected by the AioContext
      lock, we cannot use bdrv_ref/bdrv_unref unconditionally.  Fortunately the
      protection is not needed in IOThread because only main loop can modify a graph
      with the AioContext lock held.
      Signed-off-by: NFam Zheng <famz@redhat.com>
      Message-Id: <20170418143044.12187-2-famz@redhat.com>
      Reviewed-by: NJeff Cody <jcody@redhat.com>
      Tested-by: NJeff Cody <jcody@redhat.com>
      Signed-off-by: NFam Zheng <famz@redhat.com>
      178bd438
    • G
      9pfs: local: set the path of the export root to "." · 9c6b899f
      Greg Kurz 提交于
      The local backend was recently converted to using "at*()" syscalls in order
      to ensure all accesses happen below the shared directory. This requires that
      we only pass relative paths, otherwise the dirfd argument to the "at*()"
      syscalls is ignored and the path is treated as an absolute path in the host.
      This is actually the case for paths in all fids, with the notable exception
      of the root fid, whose path is "/". This causes the following backend ops to
      act on the "/" directory of the host instead of the virtfs shared directory
      when the export root is involved:
      - lstat
      - chmod
      - chown
      - utimensat
      
      ie, chmod /9p_mount_point in the guest will be converted to chmod / in the
      host for example. This could cause security issues with a privileged QEMU.
      
      All "*at()" syscalls are being passed an open file descriptor. In the case
      of the export root, this file descriptor points to the path in the host that
      was passed to -fsdev.
      
      The fix is thus as simple as changing the path of the export root fid to be
      "." instead of "/".
      
      This is CVE-2017-7471.
      
      Cc: qemu-stable@nongnu.org
      Reported-by: NLéo Gaspard <leo@gaspard.io>
      Signed-off-by: NGreg Kurz <groug@kaod.org>
      Reviewed-by: NEric Blake <eblake@redhat.com>
      Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
      9c6b899f
  5. 12 4月, 2017 1 次提交
  6. 11 4月, 2017 6 次提交