RHEL6: Deadlock on frozen ext4 filesystem, one process stuck in thaw_bdev waiting on semaphore held by flush thread doing writeback and stuck in start_this_handle

Solution Unverified - Updated -


  • vmtoolsd froze a filesystem and was not able to thaw it because it was stuck due to the filesystem's frozen journal
  • vmtoolsd hang during snapshot operation, when calling ioctl FITHAW operation
  • process is stuck in thaw_bdev waiting inside rwsem_down_write_failed
  • flush thread holding semaphore doing writeback and stuck in start_this_handle


  • Redhat Enterprise Linux 6
    • kernels prior to 2.6.32-358.el6
  • ext4 filesystem
  • VMWare guest
  • fsfreeze
  • vmtoolsd

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