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[netCDF #KLM-754067]: netCDF 4.2.1 segfaults when adding/changing attribute _FillValue

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  • Subject: [netCDF #KLM-754067]: netCDF 4.2.1 segfaults when adding/changing attribute _FillValue
  • Date: Tue, 07 Aug 2012 13:15:36 -0600
Hi Florian,

> it seems to be impossible adding the attribute _FillValue to an existing
> netCDF4 file or changing an existing attribute with this name. NetCDF
> segfaults because of a NULL-pointer access (NC_DIM_INFO_T) in
> var_create_dataset().
> 
> Note: The same works fine with classic file.
> 
> Find attached the debugger output and a C-example to reproduce this
> failure.

Thanks for reporting this bug and providing a simple example with which it
can be demonstrated.  I've duplicated the problem here, but don't have a fix 
for it yet.  I've also entered it into our issues tracking system here:

  https://www.unidata.ucar.edu/jira/browse/NCF-187

in case you want to follow status of this bug, which I hope we'll fix before 
the 4.3 release.

--Russ

> Program received signal EXC_BAD_ACCESS, Could not access memory.
> Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000014
> 0x00000001000a8cfd in var_create_dataset (grp=0x100938fa0, var=0x100943350, 
> write_dimid=0) at nc4hdf.c:1387
> 1387           if (var->dim[d]->unlimited)
> (gdb) bt
> #0  0x00000001000a8cfd in var_create_dataset (grp=0x100938fa0, 
> var=0x100943350, write_dimid=0) at nc4hdf.c:1387
> #1  0x00000001000aac1d in write_var (var=0x100943350, grp=0x100938fa0, 
> write_dimid=0) at nc4hdf.c:2222
> #2  0x00000001000ab68d in nc4_rec_write_metadata (grp=0x100938fa0) at 
> nc4hdf.c:2485
> #3  0x000000010009accc in sync_netcdf4_file (h5=0x10093fe90) at nc4file.c:2884
> #4  0x000000010009aec0 in close_netcdf4_file (h5=0x10093fe90, abort=0) at 
> nc4file.c:2950
> #5  0x000000010009b213 in NC4_close (ncid=65536) at nc4file.c:3079
> #6  0x0000000100008e24 in nc_close (ncid=65536) at dfile.c:1049
> #7  0x0000000100000e54 in main () at nc4test3.c:66
> (gdb) p *var
> $1 = {
> name = 0x100943430 "var_name",
> hdf5_name = 0x0,
> ndims = 1,
> dimids = 0x1009429b0,
> dim = 0x1009428f0,
> varid = 0,
> natts = 0,
> next = 0x0,
> prev = 0x0,
> dirty = 1,
> created = 1,
> written_to = 0,
> dimscale_attached = 0x1009435e0,
> type_info = 0x100943550,
> xtype = 5,
> hdf_datasetid = 83886081,
> att = 0x1009434d0,
> no_fill = 0,
> fill_value = 0x1009435d0,
> chunksizes = 0x0,
> contiguous = 1,
> parallel_access = 0,
> dimscale = 0,
> dimscale_hdf5_objids = 0x1009435f0,
> deflate = 0,
> deflate_level = 0,
> shuffle = 0,
> fletcher32 = 0,
> options_mask = 0,
> pixels_per_block = 0,
> chunk_cache_size = 1048576,
> chunk_cache_nelems = 521,
> chunk_cache_preemption = 0.75,
> sdsid = 0,
> hdf4_data_type = 0,
> diskless_data = 0x0
> }
> (gdb) p *var->dim
> $2 = (NC_DIM_INFO_T *) 0x0
> 
> 
> 
Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: KLM-754067
Department: Support netCDF
Priority: Normal
Status: Closed