bug#48064: texlive-* packages fail to build non-deterministically

[Ludovic Courtès]

Hello,

While investigating luatex crashes in the TeX Live 2020 package of
GNU Guix¹, we identified the following heap corruption reported by
Valgrind (this is on GNU/Linux, with glibc 2.33):

--8<---------------cut here---------------start------------->8---
sh-5.0$  ~ludo/.guix-profile/bin/valgrind 
--extra-debuginfo-path=/gnu/store/f933bvd6ab6l2lg6xl6k1a6jwvcls0z6-glibc-2.33-debug/lib/debug
 "luatex" "-interaction=nonstopmode" "-output-directory=build" "&luatex" 
"amsbsy.dtx"
==28531== Memcheck, a memory error detector
==28531== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==28531== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
==28531== Command: luatex -interaction=nonstopmode -output-directory=build 
&luatex amsbsy.dtx
==28531== 
This is LuaTeX, Version 1.12.0 (TeX Live 2020) 
 restricted system commands enabled.
==28531== Invalid write of size 8
==28531==    at 0x485C691: lua_pushlstring (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x568E03: load_hyphenation (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x56B41C: undump_language_data (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4DFB9F: load_fmt_file (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4EF0ED: main_body (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x45118D: main (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==  Address 0xae14170 is 0 bytes after a block of size 1,168 alloc'd
==28531==    at 0x483EBE1: realloc (in 
/gnu/store/jlmh0jbgr6zn4iyvhfbvxps8pykzj5ry-valgrind-3.16.1/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==28531==    by 0x46695D: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x486D932: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x48660F2: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x4868BE7: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x4868FCF: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x486988B: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x485C6BB: lua_pushlstring (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x568E03: load_hyphenation (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x56B41C: undump_language_data (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4DFB9F: load_fmt_file (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4EF0ED: main_body (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531== 
==28531== Invalid write of size 4
==28531==    at 0x485C6A2: lua_pushlstring (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x568E03: load_hyphenation (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x56B41C: undump_language_data (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4DFB9F: load_fmt_file (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4EF0ED: main_body (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x45118D: main (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==  Address 0xae14178 is 8 bytes after a block of size 1,168 alloc'd
==28531==    at 0x483EBE1: realloc (in 
/gnu/store/jlmh0jbgr6zn4iyvhfbvxps8pykzj5ry-valgrind-3.16.1/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==28531==    by 0x46695D: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x486D932: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x48660F2: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x4868BE7: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x4868FCF: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x486988B: ??? (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x485C6BB: lua_pushlstring (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/lib/libtexlua53.so.5.3.5)
==28531==    by 0x568E03: load_hyphenation (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x56B41C: undump_language_data (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4DFB9F: load_fmt_file (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531==    by 0x4EF0ED: main_body (in 
/gnu/store/w20xxg8p0wksbrxxvj3y46fngvr3954w-texlive-bin-20200406/bin/luatex)
==28531== 

[...]

valgrind: m_mallocfree.c:305 (get_bszB_as_is): Assertion 'bszB_lo == bszB_hi' 
failed.
valgrind: Heap block lo/hi size mismatch: lo = 1232, hi = 68.
This is probably caused by your program erroneously writing past the
end of a heap block and corrupting heap metadata.  If you fix any
invalid writes reported by Memcheck, this assertion failure will
probably go away.  Please try that before reporting this as a bug.
--8<---------------cut here---------------end--------------->8---

Does that ring a bell?  Is there a chance this problem was fixed in the
meantime?

Thanks in advance,
Ludovic.

¹ https://issues.guix.gnu.org/48064