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

[Norbert Lange]

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