[gdal-dev] Multithread deadlock
even.rouault at spatialys.com
Thu Sep 29 16:04:49 PDT 2016
> I don't think this comes from GDALPam, but rather from the lower level
> machinery of GDALRasterBand & GDALRasterBlock. As I said before, multi-
> threaded writing has never properly worked and I'm not sure if the issue
> you see is just an implementation bug or a design bug.
OK, after investigation, it was just an implementation bug. A lack of mutex in
GetLockedBlock() that caused IReadBlock() & IWriteBlock() to be called from 2
different threads on the same dataset.
Fixed per https://trac.osgeo.org/gdal/ticket/6665
I think the issue was mostly due to using the low level
GetLockedBlock()/MarkDirty()/DropLock() interfaces, and that people using
RasterIO(GF_Read/GF_Write) should be immune to that bug due to locks being
already taken at that stage.
Anyway fixed now (with a new test case similar to yours). Thanks for the
Spatialys - Geospatial professional services
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