[ET Trac] [Einstein Toolkit] #1473: Carpet segfaults in Shutdown

[Einstein Toolkit]

#1473: Carpet segfaults in Shutdown
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  Reporter:  knarf   |       Owner:  eschnett           
      Type:  defect  |      Status:  new                
  Priority:  minor   |   Milestone:                     
 Component:  Carpet  |     Version:  development version
Resolution:          |    Keywords:                     
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Comment (by rhaas):

 I agree PUGH's and Carpet's current behaviour if perfectly well defined.
 Since these error are very hard to track down (for example it seems that
 Philipp's recovery issue on bluewaters is due to this problem after all) I
 would also suggest that CarpetIOHDF5/IOHDF5 warn with level 1 if the array
 size in the checkpoint does not agree with the current one.

 The typical case (similar thing can happen I think with vectors of
 SCALARS) where this fails is something like this:
 {{{
 CCTK_REAL myscalar TYPE=ARRAY DIM=1 SIZE=numberofthingummies
 DISTRIB=constant "some number of things"

 for(int i = 0 ; i < numberofthingummies ; i++) { do_something(); }
 }}}
 which is very common (eg Carpet does it, the PITTNullCode does it,
 ZelmaniLeak does it). Right now CarpetIOHDF5 will abort the array grows (I
 think) since then it can be read only partially from file, while shrinking
 the array (which is what happened in the testsuite) is not caught and can
 cause memory corruption.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/1473#comment:8>
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