[Bug sanitizer/84761] New: AddressSanitizer is not compatible with glibc 2.27 on x86

["vincent-gcc at vinc17 dot net" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84761

            Bug ID: 84761
           Summary: AddressSanitizer is not compatible with glibc 2.27 on
                    x86
           Product: gcc
           Version: 8.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vincent-gcc at vinc17 dot net
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

After an upgrade to glibc 2.27 on a Debian/unstable machine, on a program that
does nothing, the AddressSanitizer segfaults with the 32-bit x86 ABI.

I have the following gcc-snapshot script:

#!/bin/sh
LD_LIBRARY_PATH=/usr/lib/gcc-snapshot/lib:$LD_LIBRARY_PATH
PATH=/usr/lib/gcc-snapshot/bin:$PATH
rpath=""
OLD_IFS="$IFS"
IFS=:
for i in $LD_RUN_PATH
do
  rpath="$rpath -Wl,-rpath -Wl,$i"
done
IFS="$OLD_IFS"
exec gcc -Wl,-rpath -Wl,/usr/lib/gcc-snapshot/lib \
         -Wl,-rpath -Wl,/usr/lib/gcc-snapshot/lib32 \
         -Wl,-rpath -Wl,/usr/lib/gcc-snapshot/libx32 $rpath "$@"

cventin:~> gcc-snapshot --version
gcc (Debian 20180216-1) 8.0.1 20180216 (experimental) [trunk revision 257720]
[...]
cventin:~> cat tst.c
int main (void)
{
  return 0;
}
cventin:~> gcc-snapshot -m32 -fsanitize=address tst.c -o tst
cventin:~> ./tst
AddressSanitizer:DEADLYSIGNAL
=================================================================
==25032==ERROR: AddressSanitizer: SEGV on unknown address 0xf7fa7e70 (pc
0xf7fa7e84 bp 0xffbf40ac sp 0xffbf406c T16777215)
==25032==The signal is caused by a WRITE memory access.
    #0 0xf7fa7e83 in _dl_get_tls_static_info (/lib/ld-linux.so.2+0x11e83)
    #1 0xf7ac147d  (/usr/lib/gcc-snapshot/lib32/libasan.so.5+0x10e47d)
    #2 0xf7aafd27  (/usr/lib/gcc-snapshot/lib32/libasan.so.5+0xfcd27)
    #3 0xf7fa591a  (/lib/ld-linux.so.2+0xf91a)
    #4 0xf7f96cb9  (/lib/ld-linux.so.2+0xcb9)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/ld-linux.so.2+0x11e83) in
_dl_get_tls_static_info
==25032==ABORTING

My original bug report:
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892096

The explanations given by Aurelien Jarno:

------------------------------------------------------------
The AddressSanitizer is using glibc internal functions though dlsym(), and such
functions have the right to change in new major versions:

From libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc:
|  void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");

And on the glibc side:
| $ readelf -s /lib/ld-linux.so.2  | grep _dl_get_tls_static_info
|      4: 00011e70    35 FUNC    GLOBAL DEFAULT   12
_dl_get_tls_static_info@@GLIBC_PRIVATE

This has been discussed for example there:
https://www.sourceware.org/ml/libc-alpha/2018-02/msg00611.html

The AddressSanitizer people should discuss for a public API so that it doesn't
happen again. Otherwise it might break at every new glibc version.
------------------------------------------------------------

In the mean time, it should at least be made compatible with glibc 2.27.