[SCIP] segmentation fault while using LProw functions

[Ambros Gleixner]

Hi Naga,

You would need to give us more details, e.g., how do you obtain the row 
pointer that you are trying to print.

Have you run it through valgrind?

(A random guess: You did not capture the row and somehow SCIP removed 
and freed it in between because it did not need it anymore and the row's 
use counter dropped to zero.  But it's hard to tell without further 
details.)

Best,
Ambros


Am 28.07.20 um 12:26 schrieb Naga Venkata Chaitanya Gudapati - 
nagavenkata.gudapati at studio.unibo.it:
> Hello SCIP community,
> 
> I am getting a  segmentation fault and it only happens when I am running a particular instance.  This is happening when I try to access rows added by a constraint handler in a function of pricer (adding a new variable).
> 
> I had used SCIP compiled for debugging to identify the issue and have the following output:
> 
> 	Thread 2 received signal SIGSEGV, Segmentation fault.
> 	0x000000010093b36d in SCIProwPrint (row=0x106c4fd30, messagehdlr=0x102926cb0, file=0x0) at src/scip/lp.c:5311
> 	5311	      assert(row->cols[i] != NULL);
> 	(gdb) strace
> 	warning: Couldn't determine the static tracepoint marker to probe
> 	Static tracepoint 1 at 0x10093b36d: file src/scip/lp.c, line 5311.
> 	(gdb) bt
> 	#0  0x000000010093b36d in SCIProwPrint (row=0x106c4fd30, messagehdlr=0x102926cb0, file=0x0) at src/scip/lp.c:5311
> 	#1  0x0000000100b775bd in SCIPprintRow (scip=0x1029364c0, row=0x106c4fd30, file=0x0) at src/scip/scip_lp.c:2162
> 	#2  0x000000010004379d in ObjPricerNDSR::add_path_variable (this=0x1056e7ef0, scip=0x1029364c0, path=..., commodity_index=6, p_cost=21)
> 	    at src/pricer_NDSR.cpp:434
> 	#3  0x0000000000000000 in ?? ()
> 
> 
> I am using scip7.0.1 . Can someone kindly let me know what's the issue here?
> 
> Thanks a bunch,
> Nag
>    
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-- 
Ambros Gleixner, Research Group Mathematical Optimization Methods at 
Zuse Institute Berlin, http://www.zib.de/gleixner