Type conversion oddness in Lua spank:get_item

[GoogleCodeExporter]

We are seeing unexpected results from the Lua function spank:get_item in 
version 0.23 built as an RPM on SL6.3 (gcc 4.4.6-4).

Sample Lua program (note that the values are printed in hex):
function slurm_spank_task_init_privileged (spank)
  SPANK.log_info("NCPUS = %x", spank:get_item('S_JOB_NCPUS'))
  SPANK.log_info("UID = %x", spank:get_item('S_JOB_UID'))
end

Output (single-core job run as root):
Sep  5 19:35:43 localhost slurmd[linux0][30130]: NCPUS = 100000001
Sep  5 19:35:43 localhost slurmd[linux0][30130]: UID = 7274732000000000

It appears that the 8-byte long "val" in lua.c:l_spank_get_item_val() is only 
partially set in the call to spank_get_item(). The lower 16 bits are set when 
retrieving S_JOB_NCPUS and the lower 32 are set for S_JOB_UID.

Initializing val appeared to resolve the issue. (In replicating this problem, 
we only saw invalid UID values when lua.so was compiled with -O1 and higher. 
Invalid NCPUS values were present with no optimization.)

Regards,
John

Original issue reported on code.google.com by [email protected] on 6 Sep 2012 at 12:48

Attachments:

• slurm-spank-plugins-0.23-get_item.patch

[nlqq]

Hi there, this patch file link has become invalid, does it has backup or 0.40 version has already not need this patch ?

[grondo]

I believe this is fixed in the latest version, please see chaos/slurm-spank-plugins as the new upstream repo.