From 21ab24eeca1220aab049c6da21566e4f8d96d1ad Mon Sep 17 00:00:00 2001 From: Elliot Saba Date: Sat, 25 Jun 2022 16:08:00 +0000 Subject: [PATCH] Don't call `jl_errorf()` when we're early in bringup When calling `jl_error()` or `jl_errorf()`, we must check to see if we are so early in the bringup process that it is dangerous to attempt to construct a backtrace because the data structures used to provide line information are not properly setup. This can be easily triggered by running: ``` julia -C invalid ``` On an `i686-linux-gnu` build, this will hit the "Invalid CPU Name" branch in `jitlayers.cpp`, which calls `jl_errorf()`. This in turn calls `jl_throw()`, which will eventually call `jl_DI_for_fptr` as part of the backtrace printing process, which fails as the object maps are not fully initialized. See the below `gdb` stacktrace for details: ``` $ gdb -batch -ex 'r' -ex 'bt' --args ./julia -C invalid ... fatal: error thrown and no exception handler available. ErrorException("Invalid CPU name "invalid".") Thread 1 "julia" received signal SIGSEGV, Segmentation fault. 0xf75bd665 in std::_Rb_tree, std::_Select1st >, std::greater, std::allocator > >::lower_bound (__k=, this=0x248) at /usr/local/i686-linux-gnu/include/c++/9.1.0/bits/stl_tree.h:1277 1277 /usr/local/i686-linux-gnu/include/c++/9.1.0/bits/stl_tree.h: No such file or directory. #0 0xf75bd665 in std::_Rb_tree, std::_Select1st >, std::greater, std::allocator > >::lower_bound (__k=, this=0x248) at /usr/local/i686-linux-gnu/include/c++/9.1.0/bits/stl_tree.h:1277 #1 std::map, std::allocator > >::lower_bound (__x=, this=0x248) at /usr/local/i686-linux-gnu/include/c++/9.1.0/bits/stl_map.h:1258 #2 jl_DI_for_fptr (fptr=4155049385, symsize=symsize@entry=0xffffcfa8, slide=slide@entry=0xffffcfa0, Section=Section@entry=0xffffcfb8, context=context@entry=0xffffcf94) at /cache/build/default-amdci5-4/julialang/julia-master/src/debuginfo.cpp:1181 #3 0xf75c056a in jl_getFunctionInfo_impl (frames_out=0xffffd03c, pointer=4155049385, skipC=0, noInline=0) at /cache/build/default-amdci5-4/julialang/julia-master/src/debuginfo.cpp:1210 #4 0xf7a6ca98 in jl_print_native_codeloc (ip=4155049385) at /cache/build/default-amdci5-4/julialang/julia-master/src/stackwalk.c:636 #5 0xf7a6cd54 in jl_print_bt_entry_codeloc (bt_entry=0xf0798018) at /cache/build/default-amdci5-4/julialang/julia-master/src/stackwalk.c:657 #6 jlbacktrace () at /cache/build/default-amdci5-4/julialang/julia-master/src/stackwalk.c:1090 #7 0xf7a3cd2b in ijl_no_exc_handler (e=0xf0794010) at /cache/build/default-amdci5-4/julialang/julia-master/src/task.c:605 #8 0xf7a3d10a in throw_internal (ct=ct@entry=0xf070c010, exception=, exception@entry=0xf0794010) at /cache/build/default-amdci5-4/julialang/julia-master/src/task.c:638 #9 0xf7a3d330 in ijl_throw (e=0xf0794010) at /cache/build/default-amdci5-4/julialang/julia-master/src/task.c:654 #10 0xf7a905aa in ijl_errorf (fmt=fmt@entry=0xf7647cd4 "Invalid CPU name \"%s\".") at /cache/build/default-amdci5-4/julialang/julia-master/src/rtutils.c:77 #11 0xf75a4b22 in (anonymous namespace)::createTargetMachine () at /cache/build/default-amdci5-4/julialang/julia-master/src/jitlayers.cpp:823 #12 JuliaOJIT::JuliaOJIT (this=) at /cache/build/default-amdci5-4/julialang/julia-master/src/jitlayers.cpp:1044 #13 0xf7531793 in jl_init_llvm () at /cache/build/default-amdci5-4/julialang/julia-master/src/codegen.cpp:8585 #14 0xf75318a8 in jl_init_codegen_impl () at /cache/build/default-amdci5-4/julialang/julia-master/src/codegen.cpp:8648 #15 0xf7a51a52 in jl_restore_system_image_from_stream (f=) at /cache/build/default-amdci5-4/julialang/julia-master/src/staticdata.c:2131 #16 0xf7a55c03 in ijl_restore_system_image_data (buf=0xe859c1c0 "8'\031\003", len=125161105) at /cache/build/default-amdci5-4/julialang/julia-master/src/staticdata.c:2184 #17 0xf7a55cf9 in jl_load_sysimg_so () at /cache/build/default-amdci5-4/julialang/julia-master/src/staticdata.c:424 #18 ijl_restore_system_image (fname=0x80a0900 "/build/bk_download/julia-d78fdad601/lib/julia/sys.so") at /cache/build/default-amdci5-4/julialang/julia-master/src/staticdata.c:2157 #19 0xf7a3bdfc in _finish_julia_init (rel=rel@entry=JL_IMAGE_JULIA_HOME, ct=, ptls=) at /cache/build/default-amdci5-4/julialang/julia-master/src/init.c:741 #20 0xf7a3c8ac in julia_init (rel=) at /cache/build/default-amdci5-4/julialang/julia-master/src/init.c:728 #21 0xf7a7f61d in jl_repl_entrypoint (argc=, argv=0xffffddf4) at /cache/build/default-amdci5-4/julialang/julia-master/src/jlapi.c:705 #22 0x080490a7 in main (argc=3, argv=0xffffddf4) at /cache/build/default-amdci5-4/julialang/julia-master/cli/loader_exe.c:59 ``` To prevent this, we simply avoid calling `jl_errorf` this early in the process, punting the problem to a later PR that can update guard conditions within `jl_error*`. --- src/jitlayers.cpp | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/src/jitlayers.cpp b/src/jitlayers.cpp index eda841cbadb73..50316c258d3a0 100644 --- a/src/jitlayers.cpp +++ b/src/jitlayers.cpp @@ -814,13 +814,20 @@ namespace { SmallVector targetFeatures(target.second.begin(), target.second.end()); std::string errorstr; const Target *TheTarget = TargetRegistry::lookupTarget("", TheTriple, errorstr); - if (!TheTarget) - jl_errorf("%s", errorstr.c_str()); + if (!TheTarget) { + // Note we are explicitly not using `jl_errorf()` here, as it will attempt to + // collect a backtrace, but we're too early in LLVM initialization for that. + jl_printf(JL_STDERR, "ERROR: %s", errorstr.c_str()); + exit(1); + } if (jl_processor_print_help || (target_flags & JL_TARGET_UNKNOWN_NAME)) { std::unique_ptr MSTI( TheTarget->createMCSubtargetInfo(TheTriple.str(), "", "")); - if (!MSTI->isCPUStringValid(TheCPU)) - jl_errorf("Invalid CPU name \"%s\".", TheCPU.c_str()); + if (!MSTI->isCPUStringValid(TheCPU)) { + // Same as above, we are too early to use `jl_errorf()` here. + jl_printf(JL_STDERR, "ERROR: Invalid CPU name \"%s\".", TheCPU.c_str()); + exit(1); + } if (jl_processor_print_help) { // This is the only way I can find to print the help message once. // It'll be nice if we can iterate through the features and print our own help