[PATCH] D24736: [lsan] Prevent initialization failure with newer (2.23+) glibc in use.

Tue Sep 20 09:38:53 PDT 2016

m.ostapenko added a comment.

In https://reviews.llvm.org/D24736#546611, @m.ostapenko wrote:

> In https://reviews.llvm.org/D24736#546554, @eugenis wrote:
>
> > There are reports that MSan initialization fails on newer libc. Do we need the same change there?
>
>
> Hm, I'll check this tomorrow.

Oh, it seems that LSan actually doesn't need this stuff, because the error with malloc occurs only when **dlsym fails** to find a symbol (and this is not the case for LSan, because it intercepts only well-known symbols).

However, this is the case for MSan, running trivial program with trunk Glibc causes segfault:

  (gdb) r
  Starting program: /home/max/build/llvm/a.out 
  warning: Could not load shared library symbols for linux-vdso.so.1.
  Do you need "set solib-search-path" or "set sysroot"?
  warning: File "/home/max/install/glibc/lib/libthread_db-1.0.so" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
  To enable execution of this file add
  	add-auto-load-safe-path /home/max/install/glibc/lib/libthread_db-1.0.so
  line to your configuration file "/home/max/.gdbinit".
  To completely disable this security protection add
  	set auto-load safe-path /
  line to your configuration file "/home/max/.gdbinit".
  For more information about this security protection see the
  "Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
  	info "(gdb)Auto-loading safe path"
  warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.

  Program received signal SIGSEGV, Segmentation fault.
  0x0000000000472c61 in Lock () at /home/max/src/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc:523
  523	  CHECK_EQ(owner_, 0);
  (gdb) bt
  #0  0x0000000000472c61 in Lock () at /home/max/src/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc:523
  #1  0x000000000041d389 in GenericScopedLock () at /home/max/src/llvm/projects/compiler-rt/lib/msan/../sanitizer_common/sanitizer_mutex.h:179
  #2  GetFromAllocator () at /home/max/src/llvm/projects/compiler-rt/lib/msan/../sanitizer_common/sanitizer_allocator_primary64.h:122
  #3  0x000000000041d333 in Refill () at /home/max/src/llvm/projects/compiler-rt/lib/msan/../sanitizer_common/sanitizer_allocator_local_cache.h:106
  #4  0x000000000041cf21 in Allocate () at /home/max/src/llvm/projects/compiler-rt/lib/msan/../sanitizer_common/sanitizer_allocator_local_cache.h:51
  #5  0x000000000041ce0d in Allocate () at /home/max/src/llvm/projects/compiler-rt/lib/msan/../sanitizer_common/sanitizer_allocator_combined.h:58
  #6  0x000000000041c78e in MsanAllocate () at /home/max/src/llvm/projects/compiler-rt/lib/msan/msan_allocator.cc:134
  #7  0x00000000004254c6 in __interceptor_malloc () at /home/max/src/llvm/projects/compiler-rt/lib/msan/msan_interceptors.cc:931
  #8  0x00007ffff7de9a61 in _dl_signal_error (errcode=errcode at entry=0, objname=objname at entry=0x7fffffffe2e3 "/home/max/build/llvm/a.out", occation=occation at entry=0x7ffff7df7413 "symbol lookup error", 
      errstring=errstring at entry=0x7fffffffd900 "undefined symbol: __isoc99_printf") at dl-error.c:90
  #9  0x00007ffff7de9c1e in _dl_signal_cerror (errcode=0, objname=0x7fffffffe2e3 "/home/max/build/llvm/a.out", occation=0x7ffff7df7413 "symbol lookup error", errstring=0x7fffffffd900 "undefined symbol: __isoc99_printf") at dl-error.c:155
  #10 0x00007ffff7de52e2 in _dl_lookup_symbol_x (undef_name=0x48ba5e "__isoc99_printf", undef_map=0x7ffff7ffe170, ref=0x7fffffffda78, symbol_scope=0x7ffff7ffe4f8, version=<optimised out>, type_class=<optimised out>, flags=0, skip_map=0x7ffff7ffe170) at dl-lookup.c:874
  #11 0x00007ffff701a0ba in do_sym (handle=0xffffffffffffffff, name=0x48ba5e "__isoc99_printf", who=<optimised out>, vers=vers at entry=0x0, flags=flags at entry=2) at dl-sym.c:161
  #12 0x00007ffff701a4bd in _dl_sym (handle=<optimised out>, name=<optimised out>, who=<optimised out>) at dl-sym.c:273
  #13 0x00007ffff74af0a4 in dlsym_doit (a=a at entry=0x7fffffffdc80) at dlsym.c:50
  #14 0x00007ffff7de9c94 in _dl_catch_error (objname=0x20bdc10 <__interceptor_calloc::calloc_memory_for_dlsym+16>, errstring=0x20bdc18 <__interceptor_calloc::calloc_memory_for_dlsym+24>, mallocedp=0x20bdc08 <__interceptor_calloc::calloc_memory_for_dlsym+8>, 
      operate=0x7ffff74af090 <dlsym_doit>, args=0x7fffffffdc80) at dl-error.c:187
  #15 0x00007ffff74af53d in _dlerror_run (operate=operate at entry=0x7ffff74af090 <dlsym_doit>, args=args at entry=0x7fffffffdc80) at dlerror.c:163
  #16 0x00007ffff74af0f8 in __dlsym (handle=<optimised out>, name=<optimised out>) at dlsym.c:70
  #17 0x0000000000469010 in __interception::GetRealFunctionAddress(char const*, unsigned long*, unsigned long, unsigned long) () at /home/max/src/llvm/projects/compiler-rt/lib/interception/interception_linux.cc:23
  #18 0x0000000000457621 in InitializeCommonInterceptors () at /home/max/src/llvm/projects/compiler-rt/lib/msan/../sanitizer_common/sanitizer_common_interceptors.inc:5925
  #19 0x0000000000454fd3 in __msan::InitializeInterceptors() () at /home/max/src/llvm/projects/compiler-rt/lib/msan/msan_interceptors.cc:1471
  #20 0x000000000041b2e1 in __msan_init () at /home/max/src/llvm/projects/compiler-rt/lib/msan/msan.cc:386
  #21 0x00000000004876b6 in msan.module_ctor ()
  #22 0x000000000048770d in __libc_csu_init ()
  #23 0x00007ffff6f20cc5 in __libc_start_main (main=0x487550 <main>, argc=1, argv=0x7fffffffdf88, init=0x4876c0 <__libc_csu_init>, fini=<optimised out>, rtld_fini=<optimised out>, stack_end=0x7fffffffdf78) at ../csu/libc-start.c:245
  #24 0x000000000041a09f in _start ()

Thus, I'm removing LSan changes and adding MSan ones that fix this issue.

Repository:
  rL LLVM

https://reviews.llvm.org/D24736