Segfault in pure R code

Tue, Dec 12, 2006 12:18 PM #

I just caught a segfault:

*** caught segfault ***
address 0x99b279c, cause 'memory not mapped'

Traceback:
 1: structure(y, class = oldClass(x), row.names = attr(x, "row.names"))
 2: `[.data.frame`(gudata, -(1:5))
 3: gudata[-(1:5)]
 4: names(gudata[-(1:5)])
 5: inherits(x, "factor")
 6: is.factor(table)
 7: match(x, table, nomatch = 0)
 8: who %in% names(gudata[-(1:5)])
 9: courses("Ingrid")

when running a function 'courses' in an R package without compiled
code. Is this "possible"? I have got many segfaults when testing my
own packages, but it has always been caused by stupidities in C or
Fortran code, never with pure R code.

So, before I start debugging, I'd like to know if a segfault in pure R
code indicates  a bug in R itself, or if it can be in my function?

I have used 'courses' many times before without problems.

Thanks,

G?ran
++++++++++++++++++++++++++++++++++++++

R version 2.4.0 Patched (2006-10-29 r39744)
i686-pc-linux-gnu

G?ran Brostr?m

Peter Dalgaard

Tue, Dec 12, 2006 1:01 PM #

G?ran Brostr?m wrote:

By definition, reproducible segfaults in R code are bugs in R, unless 
caused by abuse of .C calls or similar. (Irreproducible ones are often 
hardware faults.)

However, at least presently, you are the only one with a handle on the 
bug. So either you get to do the debugging or you have to provide 
something that others can reproduce.

Astarting point could be to run R under the debugger (R -d gdb)  and 
generate a C backtrace, then look at the variables involved.

(Further discussion should probably go on r-devel instead of r-help).

-p