There are a couple of recent GC-related bug fixes (#9045 and #9001). Before trying to track this down any further I suggest you try using the tip of the ghc-7.8 branch with commit fc0ed8a730 cherry-picked on top.
Regards, Reid Barton On Wed, May 28, 2014 at 6:04 AM, Ömer Sinan Ağacan <[email protected]>wrote: > Hi all, > > I'm suffering from a RTS bug(probably GC related) that makes making > progress in my GSoC project impossible. I have very limited knowledge > of GHC internals and I currently have no idea how to produce a minimal > program that demonstrates the bug. I wrote how to reproduce it and gdb > backtrace when segfault happens in a short blog post: > http://osa1.net/posts/2014-05-27-worst-bug.html . As also written in > the blog post, changing generation count of generational GC will makes > the bug disappear in some cases, but it's not a solution. > > I also pasted backtrace output below for those who don't want to click > links. > > GHC version used is 7.8.2. > > If anyone give me some pointers to understand what's going wrong or > how can I produce a simple program that demonstrates the bug, I'd like > to work on that. I'm basically stuck and I can't make any progress > with this bug. > > Thanks, > Ömer > > [ 5 of 202] Compiling GHC.Unicode[boot] ( GHC/Unicode.hs-boot, > dist/build/GHC/Unicode.js_p_o-boot ) > Detaching after fork from child process 3382. > [ 6 of 202] Compiling GHC.IO[boot] ( GHC/IO.hs-boot, > dist/build/GHC/IO.js_p_o-boot ) > Detaching after fork from child process 3383. > [ 7 of 202] Compiling GHC.Exception[boot] ( GHC/Exception.lhs-boot, > dist/build/GHC/Exception.js_p_o-boot ) > Detaching after fork from child process 3384. > [ 51 of 202] Compiling GHC.Fingerprint[boot] ( > GHC/Fingerprint.hs-boot, dist/build/GHC/Fingerprint.js_p_o-boot ) > Detaching after fork from child process 3385. > [ 55 of 202] Compiling GHC.IO.Exception[boot] ( > GHC/IO/Exception.hs-boot, dist/build/GHC/IO/Exception.js_p_o-boot ) > Detaching after fork from child process 3386. > [ 75 of 202] Compiling Foreign.C.Types ( Foreign/C/Types.hs, > dist/build/Foreign/C/Types.js_p_o ) > > Program received signal SIGSEGV, Segmentation fault. > 0x000000000425d5c4 in LOOKS_LIKE_CLOSURE_PTR (p=0x0) at > includes/rts/storage/ClosureMacros.h:258 > 258 includes/rts/storage/ClosureMacros.h: No such file or directory. > (gdb) bt > #0 0x000000000425d5c4 in LOOKS_LIKE_CLOSURE_PTR (p=0x0) at > includes/rts/storage/ClosureMacros.h:258 > #1 0x000000000425f776 in scavenge_mutable_list1 (bd=0x7fffe5c02a00, > gen=0x4d1fd48) at rts/sm/Scav.c:1400 > #2 0x000000000425fa13 in scavenge_capability_mut_Lists1 > (cap=0x4cfe5c0 <MainCapability>) at rts/sm/Scav.c:1493 > #3 0x0000000004256b66 in GarbageCollect (collect_gen=0, > do_heap_census=rtsFalse, gc_type=2, > cap=0x4cfe5c0 <MainCapability>) at rts/sm/GC.c:342 > #4 0x00000000042454a3 in scheduleDoGC (pcap=0x7fffffffc198, > task=0x4d32b60, force_major=rtsFalse) > at rts/Schedule.c:1650 > #5 0x0000000004243de4 in schedule (initialCapability=0x4cfe5c0 > <MainCapability>, task=0x4d32b60) > at rts/Schedule.c:553 > #6 0x0000000004246436 in scheduleWaitThread (tso=0x7ffff6708d60, > ret=0x0, pcap=0x7fffffffc2c0) at rts/Schedule.c:2346 > #7 0x000000000423e9b4 in rts_evalLazyIO (cap=0x7fffffffc2c0, > p=0x477f850, ret=0x0) at rts/RtsAPI.c:500 > #8 0x0000000004241666 in real_main () at rts/RtsMain.c:63 > #9 0x0000000004241759 in hs_main (argc=237, argv=0x7fffffffc448, > main_closure=0x477f850, rts_config=...) > at rts/RtsMain.c:114 > #10 0x0000000000408ea7 in main () > _______________________________________________ > ghc-devs mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/ghc-devs >
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