2 Replies Latest reply on Aug 11, 2017 2:35 AM by rwd4ever

    New Ryzen FMA bug


      Hi all,

      There is one more bug in Ryzen CPU, which still exists after BIOS update to version AGESA It affects Ryzen users of TN-Grid projects who want to use FMA app version. Apps without FMA instructions (AVX, SSE2) are fine. What is interesting, crash signature is always the same:

      Privileged Instruction (0xc0000096) at address 0x00000000004f5458

      I am author of this app, so I did some analysis and found that for some reason Ryzen loads instruction from incorrect address (in the middle of valid one). This invalid instruction is STI which is a privileged one, what causes crash.

      More details are on TN-Grid project forum: http://gene.disi.unitn.it/test/forum_thread.php?id=167