id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
2192	occasional segmentation faults when using Control.Parallel	ivant	igloo	"The attached program fails quite often with segmentation faults or internal errors (unpredictably, in consecutive runs, without changing the source):
{{{
% time ./parallel +RTS -N2                                   
zsh: segmentation fault (core dumped)  ./parallel +RTS -N2
./parallel +RTS -N2  2.79s user 0.42s system 107% cpu 2.988 total

% time ./parallel +RTS -N2
parallel: internal error: evacuate: strange closure type 65284
    (GHC version 6.8.2 for i386_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
zsh: abort (core dumped)  ./parallel +RTS -N2
./parallel +RTS -N2  3.60s user 0.51s system 108% cpu 3.781 total

% time ./parallel +RTS -N2
zsh: segmentation fault (core dumped)  ./parallel +RTS -N2
./parallel +RTS -N2  5.09s user 0.46s system 111% cpu 4.982 total

% time ./parallel +RTS -N2
500000
./parallel +RTS -N2  8.34s user 0.14s system 108% cpu 7.796 total
}}}

The program can fail both when it is compiled with and without -O2.
Changing the value of maxSparks makes a difference (with value 2 it is finishing successfully always (or probably more often))."	merge	closed	normal	6.8.3	Runtime System	6.8.2	fixed	par		Linux	x86		Unknown