Patches have now been committed to QEMU which fix the subset of "multithreaded guests crash" which this bug covers [ie ones where there was a race between tb_unlink_cpu() and the cpu thread using or modifying the TB graph], so I'm closing this bug.
Note that there are still other classes of QEMU bug which also manifest as "my multithreaded guest crashes" -- those are covered by LP:1098729.
Patches have now been committed to QEMU which fix the subset of "multithreaded guests crash" which this bug covers [ie ones where there was a race between tb_unlink_cpu() and the cpu thread using or modifying the TB graph], so I'm closing this bug.
Note that there are still other classes of QEMU bug which also manifest as "my multithreaded guest crashes" -- those are covered by LP:1098729.