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  1. HPCC
  2. HPCC-17543

Segmentation fault in eclblas::dgemm

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 6.4.0
    • Component/s: Code Generator, Plugins
    • Labels:
      None

      Description

      I had the following crash when running one of the ML examples:

      Program terminated with signal SIGSEGV, Segmentation fault.
      #0  0x00007f20c7ea81e7 in eclblas::dgemm (__isAllResult=<optimised out>, __lenResult=@0x7f20c0d61d48: 128, __result=@0x7f20c0d61dd0: 0x0, 
          transposeA=<optimised out>, transposeB=<optimised out>, m=4, n=4, k=9, alpha=1, isAllA=false, lenA=288, A=0x7f20c50b3d80, isAllB=false, 
          lenB=288, B=0x7f20c9e80097, beta=1, isAllC=false, lenC=128, C=0x7f20c9bc02d7) at /home/gavin/dev/hpcc/plugins/eclblas/dgemm.cpp:38
      

      Causes by the following instuction:

         0x00007f20c7ea81d9 <+297>:	mov    %rdi,%r10
         0x00007f20c7ea81dc <+300>:	add    0xb0(%rsp),%r10
         0x00007f20c7ea81e4 <+308>:	add    %rbx,%rdi
      => 0x00007f20c7ea81e7 <+311>:	movapd (%r10,%rax,1),%xmm0
         0x00007f20c7ea81ed <+317>:	add    $0x1,%edx
         0x00007f20c7ea81f0 <+320>:	movups %xmm0,(%rdi,%rax,1)
         0x00007f20c7ea81f4 <+324>:	add    $0x10,%rax
      

      movapd requires that the source is 16byte aligned, but our sets of doubles will not be. Even if the code didn't crash the non aligned access may affect performance.

      Richard Chapman John Holt not quite sure how to fix...

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            • Assignee:
              ghalliday Gavin Halliday
              Reporter:
              ghalliday Gavin Halliday
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              • Created:
                Updated:
                Resolved: