[Rcpp-devel] memory not mapped with Rcpp on Ubuntu

[Serguei Sokol]

Hi John,

Le 13/02/2025 à 15:17, John Clarke a écrit :
> Hey folks,
> 
> I've been developing an Rcpp package on my Mac and testing on Mac and 
> Windows. I also have been testing on linux-latest with the standard 
> Github action which runs the CMD check. These passed without any problem 
> until I implemented a test suite (testthat) and increased the test 
> coverage to include additional calls. It turns out that the two main 
> functions (and maybe others) that I wrote cause a segfault on Ubuntu 
> builds. Several versions on Linux are tested and all fail.
> 
> It appears to be related to Rcpp so I'm wondering if you've encountered 
> this before and how I might go about finding a solution. I can reproduce 
> the error on a local docker image consistently, but... I don't have the 
> debugging tools I"m used to on MacOS via VS Code to help me step through 
> when the error occurs. And I suspect it has to do with a mismatched 
> library version because the tests pass fine on Windows and MacOS. So not 
> sure if debugging would help much.
> 
> Is there a known configuration/compiling issue/fix that I could try? 
You can see some techniques e.g. here 
https://github.com/wch/r-debug/blob/master/debugging-r.md
In short, if you already have a docker image, you can compile you code 
there with "-g -O0" options and run it in:

R -d gdb
(gdb) run
<run your R/Rcpp (test)code. An error will bring you back to gdb where 
you can check relevant frames, parameters, cals and so on.>

Hoping it helps,
Best,
Serguei.


> Apart from installing a full fledged instance of Ubuntu with VS Code and 
> debugger, is there a way I can get closer to finding out what the issue is?
> 
> Clip from the failed R error messages when I call  
> shg$runSimFromFixedValues(N, 0, 0, 1940):
> 
>   *** caught segfault ***
> address (nil), cause 'memory not mapped'
> 
> Traceback:
>   1: .External(list(name = "CppMethod__invoke_notvoid", address = 
> <pointer: 0x55efab6ef710>,     dll = list(name = "Rcpp", path = "/usr/ 
> local/lib/R/site-library/Rcpp/libs/Rcpp.so",         dynamicLookup = 
> TRUE, handle = <pointer: 0x55efa9b64b30>,         info = <pointer: 
> 0x55efaa89aaa0>, forceSymbols = FALSE),     numParameters = -1L), 
> <pointer: 0x55efae9ae1f0>, <pointer: 0x55efaf2399d0>,     .pointer, ...)
>   2: shg$runSimFromFixedValues(N, 0, 0, 1940)
> 
> Thanks,
> 
> -John
> 
> John Clarke | Senior Technical Advisor |
> Cornerstone Systems Northwest | john.clarke at cornerstonenw.com 
> <mailto:john.clarke at cornerstonenw.com>
> 
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