Bug#842642: clang-3.9: memory sanitizer segfaults immediately

[Norbert Lange]

The same 2 patches also apply to toolchain 3.8.1-15 (with some
offsets), but I haven`t testing building it

2016-11-11 1:25 GMT+01:00 Norbert Lange <nolange79 at gmail.com>:
> BTW. make check-sanitizer would have likely found this issue, might
> want to enable it?
> I believe it knows which sanitizers should work
>
> 2016-11-11 0:46 GMT+01:00 Norbert Lange <nolange79 at gmail.com>:
>> Tags: patch
>>
>>
>> Hi,
>>
>> I got it working, seems that from the 3 related patched, one is already applied.
>> The attached archive is the 3 patches and a edited "series" file,
>> it should be painless for you to integrate it into the debian/patches
>> directory for 3.9
>>
>> I did not try with 3.8 yet (possibly more difficult), building llvm
>> takes quite a while.
>>
>> Kind Regards,
>> Norbert
>>
>> 2016-11-09 11:04 GMT+01:00 Norbert Lange <nolange79 at gmail.com>:
>>> Hi,
>>>
>>> researched a bit further and the same compiled programm will run fine
>>> on debian jessie.
>>> I tracked it down to being caused by a newer glibc version [1][2],
>>> apparently during loading of shared libs, glibc can now allocate
>>> memory which messes up sanitzers (mostly in more subtile ways than the
>>> memory sanitizer).
>>>
>>> The result is, that if stretch will ship with the current glibc, clang
>>> and gcc (I dont think its patched there either), then the sanitizers
>>> won`t be usable.
>>> 1) revert the fix in glibc. Would have the advantage that "sanitized"
>>> binaries compiled from current and older clang/gcc versions will work
>>> 2) adopt the fixed from upstream [3][4] (possibly more) into clang
>>> (and possibly gcc).
>>> or maybe both?
>>>
>>> Kind Regards,
>>> Norbert
>>>
>>> PS. shouldn`t the testsuite catch these bugs?
>>>
>>> [1] https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=24e2b1cede1952d7d4411a3cafd25dd8593dab9f
>>> [2] https://llvm.org/bugs/show_bug.cgi?id=27310
>>> [3] https://github.com/llvm-mirror/compiler-rt/commit/827ea206c1078fc7c7da287984a7ba4563390589
>>> [4] https://github.com/llvm-mirror/compiler-rt/commit/570ee9dd7a6f90b0370a86535cbde6738d0ccf67
>>>
>>> 2016-10-31 21:43 GMT+01:00 Norbert Lange <nolange79 at gmail.com>:
>>>> On Mon, 31 Oct 2016 08:38:21 +0100 Sylvestre Ledru <sylvestre at debian.org> wrote:
>>>>> Le 31/10/2016 à 00:39, Norbert Lange a écrit :
>>>>> > Package: clang-3.9
>>>>> > Version: 1:3.9-2
>>>>> > Severity: normal
>>>>> >
>>>>> > Dear Maintainer,
>>>>> >
>>>>> > The memory sanitizer is unusable as it segfaults during initialization.
>>>>> > To reproduce:
>>>>> > echo 'int main() { return 0; }' >/tmp/test.c
>>>>> > clang -fsanitize=memory -o test test.c
>>>>> can you try with clang-3.9 instead?
>>>>
>>>> Same thing, output:
>>>>
>>>> $ clang-3.9 -fsanitize=memory -o test test.c -v
>>>> clang version 3.9.0-2 (tags/RELEASE_390/final)
>>>> Target: x86_64-pc-linux-gnu
>>>> Thread model: posix
>>>> InstalledDir: /usr/bin
>>>> Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/6
>>>> Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/6.2.0
>>>> Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5
>>>> Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.1
>>>> Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6
>>>> Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0
>>>> Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6
>>>> Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6.2.0
>>>> Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
>>>> Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.1
>>>> Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
>>>> Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.2.0
>>>> Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0
>>>> Candidate multilib: .;@m64
>>>> Candidate multilib: 32;@m32
>>>> Candidate multilib: x32;@mx32
>>>> Selected multilib: .;@m64
>>>>  "/usr/lib/llvm-3.9/bin/clang" -cc1 -triple x86_64-pc-linux-gnu
>>>> -emit-obj -mrelax-all -disable-free -disable-llvm-verifier
>>>> -discard-value-names -main-file-name test.c -mrelocation-model static
>>>> -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose
>>>> -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu
>>>> x86-64 -v -dwarf-column-info -debugger-tuning=gdb -resource-dir
>>>> /usr/lib/llvm-3.9/bin/../lib/clang/3.9.0 -internal-isystem
>>>> /usr/local/include -internal-isystem
>>>> /usr/lib/llvm-3.9/bin/../lib/clang/3.9.0/include
>>>> -internal-externc-isystem /usr/include/x86_64-linux-gnu
>>>> -internal-externc-isystem /include -internal-externc-isystem
>>>> /usr/include -fdebug-compilation-dir /tmp -ferror-limit 19
>>>> -fmessage-length 135 -fsanitize=memory
>>>> -fsanitize-blacklist=/usr/lib/llvm-3.9/bin/../lib/clang/3.9.0/msan_blacklist.txt
>>>> -fno-assume-sane-operator-new -fobjc-runtime=gcc
>>>> -fdiagnostics-show-option -fcolor-diagnostics -o /tmp/test-2d4d2c.o -x
>>>> c test.c
>>>> clang -cc1 version 3.9.0 based upon LLVM 3.9.0 default target
>>>> x86_64-pc-linux-gnu
>>>> ignoring nonexistent directory "/include"
>>>> #include "..." search starts here:
>>>> #include <...> search starts here:
>>>>  /usr/local/include
>>>>  /usr/lib/llvm-3.9/bin/../lib/clang/3.9.0/include
>>>>  /usr/include/x86_64-linux-gnu
>>>>  /usr/include
>>>> End of search list.
>>>>  "/usr/bin/ld" --hash-style=both --eh-frame-hdr -m elf_x86_64
>>>> -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o test
>>>> /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/../../../x86_64-linux-gnu/crt1.o
>>>> /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/../../../x86_64-linux-gnu/crti.o
>>>> /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/crtbegin.o
>>>> -L/usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0
>>>> -L/usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/../../../x86_64-linux-gnu
>>>> -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu
>>>> -L/usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/../../..
>>>> -L/usr/lib/llvm-3.9/bin/../lib -L/lib -L/usr/lib -whole-archive
>>>> /usr/lib/llvm-3.9/bin/../lib/clang/3.9.0/lib/linux/libclang_rt.msan-x86_64.a
>>>> -no-whole-archive
>>>> --dynamic-list=/usr/lib/llvm-3.9/bin/../lib/clang/3.9.0/lib/linux/libclang_rt.msan-x86_64.a.syms
>>>> /tmp/test-2d4d2c.o --no-as-needed -lpthread -lrt -lm -ldl -lgcc
>>>> --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s
>>>> --no-as-needed /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/crtend.o
>>>> /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0/../../../x86_64-linux-gnu/crtn.o