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[msan] Prevent initialization failure with newer (2.23+) glibc in use.
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Authored by m.ostapenko on Sep 19 2016, 10:55 AM.

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rL LLVM

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m.ostapenko retitled this revision from to [lsan] Prevent initialization failure with newer (2.23+) glibc in use..
m.ostapenko updated this object.
m.ostapenko added reviewers: kcc, eugenis.
m.ostapenko set the repository for this revision to rL LLVM.
m.ostapenko added a project: Restricted Project.
m.ostapenko added subscribers: llvm-commits, ygribov.
kcc accepted this revision.Sep 19 2016, 10:59 AM
kcc edited edge metadata.

LGTM

This revision is now accepted and ready to land.Sep 19 2016, 10:59 AM
eugenis edited edge metadata.Sep 19 2016, 11:07 AM

There are reports that MSan initialization fails on newer libc. Do we need the same change there?

There are reports that MSan initialization fails on newer libc. Do we need the same change there?

Hm, I'll check this tomorrow.

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@entry=0, objname=objname@entry=0x7fffffffe2e3 "/home/max/build/llvm/a.out", occation=occation@entry=0x7ffff7df7413 "symbol lookup error", 
    errstring=errstring@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@entry=0x0, flags=flags@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@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@entry=0x7ffff74af090 <dlsym_doit>, args=args@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.

m.ostapenko retitled this revision from [lsan] Prevent initialization failure with newer (2.23+) glibc in use. to [msan] Prevent initialization failure with newer (2.23+) glibc in use..
m.ostapenko updated this object.
m.ostapenko edited edge metadata.
eugenis added inline comments.Sep 20 2016, 4:07 PM
lib/msan/msan_interceptors.cc
938

Should this go to AllocateFromLocalPool if msan is still not initialized?

Right, MsanAllocatorInit is called after InitializeInterceptors. Perhaps we need the same change for ASan.

eugenis accepted this revision.Sep 22 2016, 1:44 PM
eugenis edited edge metadata.

LGTM w/ nit

lib/asan/asan_malloc_linux.cc
81

if (UNLIKELY(!asan_inited)) AllocateFromLocalPool else asan_malloc

This probably does not matter in practice, but we should not keep reallocating in the local pool when the main allocator is available.

This revision was automatically updated to reflect the committed changes.
eugenis added inline comments.Sep 23 2016, 1:22 PM
compiler-rt/trunk/lib/asan/asan_malloc_linux.cc
82 ↗(On Diff #72238)

Could you do the same in MSan?