Missing symbols while relocating libstdc++.so.6 3.4.30 and libgcc_s.so.1

[vtikoo]

While running numpy_core_tests, following symbols are missing -

$readelf --relocs appdir/usr/lib/x86_64-linux-gnu/libgcc_s.so.1 | grep dl_find_object
00000001f108 000e00000007 R_X86_64_JUMP_SLO 0000000000000000 _dl_find_object@GLIBC_2.35 + 0
$readelf --relocs appdir/usr/lib/x86_64-linux-gnu/libstdc++.so.6 | grep arc4random
000000214150 000900000007 R_X86_64_JUMP_SLO 0000000000000000 arc4random@GLIBC_2.36 + 0
$readelf --relocs appdir/usr/lib/x86_64-linux-gnu/libstdc++.so.6 | grep libc_
000000213298 003000000006 R_X86_64_GLOB_DAT 0000000000000000 __libc_single_threaded@GLIBC_2.32 + 0

arc4random can be mitigated by runtime interpositioning libbsddev.

All these symbols are part of glibc shared object file -

 $strings appdir/usr/lib/x86_64-linux-gnu/libc.so.6 | grep _dl_find_object
_dl_find_object
$strings appdir/usr/lib/x86_64-linux-gnu/libc.so.6 | grep arc4random
arc4random_uniform
arc4random_buf
arc4random
Fatal glibc error: cannot get entropy for arc4random
$strings appdir/usr/lib/x86_64-linux-gnu/libc.so.6 | grep __libc_single_threaded
__libc_single_threaded

libstdc++ version information -

$strings appdir/usr/lib/x86_64-linux-gnu/libstdc++.so.6 | grep LIBCXX
GLIBCXX_3.4
GLIBCXX_3.4.1
GLIBCXX_3.4.2
GLIBCXX_3.4.3
GLIBCXX_3.4.4
GLIBCXX_3.4.5
GLIBCXX_3.4.6
GLIBCXX_3.4.7
GLIBCXX_3.4.8
GLIBCXX_3.4.9
GLIBCXX_3.4.10
GLIBCXX_3.4.11
GLIBCXX_3.4.12
GLIBCXX_3.4.13
GLIBCXX_3.4.14
GLIBCXX_3.4.15
GLIBCXX_3.4.16
GLIBCXX_3.4.17
GLIBCXX_3.4.18
GLIBCXX_3.4.19
GLIBCXX_3.4.20
GLIBCXX_3.4.21
GLIBCXX_3.4.22
GLIBCXX_3.4.23
GLIBCXX_3.4.24
GLIBCXX_3.4.25
GLIBCXX_3.4.26
GLIBCXX_3.4.27
GLIBCXX_3.4.28
GLIBCXX_3.4.29
GLIBCXX_3.4.30
GLIBCXX_DEBUG_MESSAGE_LENGTH

libgcc_s version information -

$strings appdir/usr/lib/x86_64-linux-gnu/libgcc_s.so.1 | grep GCC
GCC_3.0
GCC_3.3
GCC_3.3.1
GCC_3.4
GCC_3.4.2
GCC_3.4.4
GCC_4.0.0
GCC_4.2.0
GCC_4.3.0
GCC_4.7.0
GCC_4.8.0
GCC_7.0.0
GCC_12.0.0

[anakrish]

For __libc_single_threaded, see

• Detecting Single-Threaded Execution
• Why glibc 2.34 removed libpthread

[vtikoo]

@radhikaj we are hitting this for .net 8 too. This seems like a musl C vs glibc difference. We could check if newer musl versions support this (I couldn't find anything promising from my cursory search). Or implement these symbols in musl ourselves.