#2502: segfault with GHC.Handle.fdToHandle'
---------------------+------------------------------------------------------
Reporter: EricKow | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 6.10 branch
Component: None | Version: 6.8.3
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: x86
Os: FreeBSD |
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Comment (by thorkilnaur):
With
{{{
$ uname -a
FreeBSD tn12.thorkilnaur.dk 6.2-RELEASE FreeBSD 6.2-RELEASE #0: Fri Jan 12
10:40:27 UTC 2007
[EMAIL PROTECTED]:/usr/obj/usr/src/sys/GENERIC i386
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.10.1
$
}}}
I can do
{{{
$ cat t1.hs
import GHC.Handle ( fdToHandle' )
import IO ( IOMode(..) )
main = fdToHandle' 1 Nothing False "stdout" WriteMode True
$ ghc -fforce-recomp --make t1.hs -threaded
[1 of 1] Compiling Main ( t1.hs, t1.o )
Linking t1 ...
$ ./t1
$ ghc -fforce-recomp --make t1.hs -threaded -optl-pthread
[1 of 1] Compiling Main ( t1.hs, t1.o )
Linking t1 ...
$ ./t1
Segmentation fault: 11 (core dumped)
$
}}}
Studying the {{{gcc}}} and {{{ld}}} command lines produced by {{{ghc}}}
using {{{-v}}}, I find that {{{-optl-pthread}}} (as one would expect) adds
{{{-pthread}}} to the {{{gcc}}} command for performing the link. This, in
turn, causes {{{-lpthread}}} to be added to the {{{ld}}} command. Now, the
{{{ld}}} command already has {{{-lthr}}} which prompted a search which
uncovered
http://planet.gentoo.org/developers/lavajoe/2007/09/17/spinning_my_tires_in_bug_mud.
According to Joe Peterson in this reference, libthr is the newer FreeBSD
threading library, replacing the older libpthread. And, again according to
the quoted reference, at least in older FreeBSDs (like the 6.2 I am using
here), mixing the two could lead to segmentation faults, in spite of
libpthread being "mapped to libthr by libmap.conf".
Summing all this up, I would say that this is a FreeBSD problem, not a GHC
problem. And, of course, the work-around is not to use the {{{-optl-
pthread}}} flag, which doesn't appear to be necessary in any case. So I
suggest that we close this ticket.
Best regards
Thorkil
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2502#comment:6>
GHC <http://www.haskell.org/ghc/>
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