Hello Fabian, after some more searching and testing here is my "opinion" on this issue:
- OCaml versions 4.01 (used in Jessie) and before are not doing stack alignment on 16 byte boundaries [1]. - GCC does 16 byte stack alignment (at least when using SSE instructions) at compile time. - Now when calling libmp3lame0 from lame executable (gcc) this works just fine. But calling from liquidsoap (ocaml) we end up calling libmp3lame0 with a unaligned stack therefore getting the SIGSEGV on the "movaps %xmm0,0x20(%esp)". (See the second stack and the address of vec_xrpow_max in [2].) But until now I could not fully proove my theory because: - OCaml version 4.02 is just in experimental. Using this version would need to compile also all the packages depending on ocaml. - Just using this patch in [1] is also not binary compatible with the packages depending on ocaml, therefore needing them all to recompile too. For this reason chances for such a change to OCaml to enter Jessie are low? One thing did avoid the crash, that was adding "__attribute__((aligned(0x20)))" to the vecfloat_union used inside libmp3lame0 [3]. Requesting an alignment of 0x10 seems without effect. (Probably because GCC does this already and is therefore removed.) Options we have, if above could be proven right: - change libmp3lame0 [3] (at least for stable), even when it is not guilty - test rebuilding OCaml and all dependents with the patch in [1] - wait if problem vanishes when OCaml 4.02 enters unstable/testing. - get someone from debian-ocaml-maint involved. [1] http://caml.inria.fr/mantis/view.php?id=6038#c11630 [2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786438#22 [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786438#87 Kind regards, Bernhard -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
