relocation error: symbol pthread_sigmask version GLIBC_2.2.5 not defined in file libc.so.6 with link time reference
lithdew opened this issue · 8 comments
Encountered this error while trying to run CI tests on Github Actions for a Zig project, using the Zig nightly bundle provided here: https://ziglang.org/builds/zig-linux-x86_64-0.7.1+dfacac916.tar.xz. Linking with musl makes the problem go away.
The latest glibc version available in Github Actions is 2.27.
root@dew:/github/workspace# ldd ./zig-cache/o/ea49ec9c878272fe2410dfdf1fc66939/test
linux-vdso.so.1 (0x00007ffe5b38e000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fa3c72c5000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fa3c6f27000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fa3c6d08000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fa3c6b04000)
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fa3c68fc000)
/lib64/ld-linux-x86-64.so.2 (0x00007fa3c76b6000)
libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007fa3c66f9000)
root@dew:/github/workspace# nm -D /lib/x86_64-linux-gnu/libpthread.so.0 | grep pthread_sig
000000000000f290 T pthread_sigmask
000000000000f3e0 T pthread_sigqueue
root@dew:/github/workspace# nm -D /lib/x86_64-linux-gnu/libc.so.6 | grep pthread_sig
root@dew:/github/workspace#
Reproduction requires an 18.2GB Docker image that emulates the Github Actions CI Environment, which can be found here: https://hub.docker.com/layers/nektos/act-environments-ubuntu/18.04/images/sha256-4d991875312e2ad084ff5350aa193e8a7dbdc4c144476d48df6a69e1e3404427
References to pthread symbols in built executable:
root@dew:/github/workspace# objdump -T ./zig-cache/o/ea49ec9c878272fe2410dfdf1fc66939/test | grep pthread
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.3.2 pthread_cond_destroy
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.3.2 pthread_cond_init
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.3.2 pthread_cond_signal
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.3.2 pthread_cond_wait
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_create
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_getspecific
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_join
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_key_create
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_key_delete
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.12 pthread_mutex_consistent
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutex_destroy
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutex_init
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutex_lock
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutex_unlock
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutexattr_destroy
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutexattr_init
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutexattr_setpshared
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.12 pthread_mutexattr_setrobust
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_self
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_setspecific
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_sigmask
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_atfork
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 pthread_mutex_trylock
hello.zig reduction (fails on issue host, works for my host)
const std = @import("std");
// hack to force symbol requirement
extern "c" var pthread_sigmask: u32;
pub fn main() !void {
const stdout = std.io.getStdOut().writer();
try stdout.print("Hello, {}!\n", .{"world"});
try stdout.print("Hello, {d}!\n", .{pthread_sigmask});
}output from readelf -a hello on archlinux w/ glibc 2.32; snipped to sections/headers that have pthread_sigmask
Dynamic section at offset 0x38f70 contains 27 entries:
Tag Type Name/Value
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x0000000000000001 (NEEDED) Shared library: [libm.so.6]
0x0000000000000001 (NEEDED) Shared library: [libpthread.so.0]
0x0000000000000001 (NEEDED) Shared library: [libdl.so.2]
0x0000000000000001 (NEEDED) Shared library: [librt.so.1]
0x0000000000000001 (NEEDED) Shared library: [ld-linux-x86-64.so.2]
0x0000000000000001 (NEEDED) Shared library: [libutil.so.1]
[SNIP]
Relocation section '.rela.dyn' at offset 0x850 contains 5 entries:
Offset Info Type Sym. Value Sym. Name + Addend
00000023b138 000100000006 R_X86_64_GLOB_DAT 0000000000000000 __libc_start_main@GLIBC_2.2.5 + 0
00000023b140 000200000006 R_X86_64_GLOB_DAT 0000000000000000 __gmon_start__ + 0
00000023a998 000300000001 R_X86_64_64 0000000000000000 __errno_location@GLIBC_2.2.5 + 0
00000023b150 000900000006 R_X86_64_GLOB_DAT 0000000000000000 environ@GLIBC_2.2.5 + 0
00000023b148 001400000006 R_X86_64_GLOB_DAT 0000000000000000 pthread_sigmask@GLIBC_2.2.5 + 0
Symbol table '.symtab' contains 928 entries:
Num: Value Size Type Bind Vis Ndx Name
[SNIP]
919: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_mutex_lock
920: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_mutex_unlock
921: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask
your quick grep on discord showed 3 matches to pthread_sigmask for the command. Can you post here?
@daurnimator found this:
https://sourceware.org/pipermail/glibc-cvs/2020q2/069412.html
TL;DR: as of glibc 2.32 symbol for pthread_sigmask moved from libpthread → libc and it might be the trigger for this issue; issue host is a glibc 2.27 system.
your quick grep on discord showed 3 matches to
pthread_sigmaskfor the command. Can you post here?
Sure:
root@dew:/github/workspace# readelf -a /root/.cache/zig/o/9ef07c7e75e1fe8f2ae6df075cfa21ed/hello | grep pthread_sigmask
00000023adb8 001400000006 R_X86_64_GLOB_DAT 0000000000000000 pthread_sigmask@GLIBC_2.2.5 + 0
20: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask@GLIBC_2.2.5 (2)
904: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask
@daurnimator found this:
https://sourceware.org/pipermail/glibc-cvs/2020q2/069412.html
TL;DR: as of
glibc 2.32symbol forpthread_sigmaskmoved fromlibpthread→libcand it might be the trigger for this issue; issue host is a glibc 2.27 system.
Hmm, is there any way to workaround this?
I also faced this issue (and suspect the same underlying cause) but was unable to find a reasonable workaround.
I am getting this too on an internal project (which requires use of glibc 2.19):
id: relocation error: /lib/x86_64-linux-gnu/libnss_uber.so.2: symbol pthread_sigmask, version GLIBC_2.2.5 not defined in file libc.so.6 with link time reference
+1 on "would be nice to find a reasonable workaround". I will try to find some time to read about linkers and hopefully find one.
It seems that the problem might be related more to dynamically loaded libraries and incorrect symbol mapping to library from zig side.
Minimal reproducible c code example in debian jessie:
a.c file compiled by running: zig cc --target=x86_64-linux-gnu.2.19 -o a a.c
#define _GNU_SOURCE
#include <dlfcn.h>
int main()
{
void *lib = dlopen("./libshared.so", RTLD_LAZY);
void (*exported_func)(void);
exported_func = (void (*)(void))dlsym(lib, "exported_func");
exported_func();
return 0;
}sharedlib.c compiled into libshared.so by running the following commands:
zig cc --target=x86_64-linux-gnu.2.19 -c -Wall -Werror -fpic sharedlib.c -o sharedlib.o
zig cc -shared -o libshared.so sharedlib.o -lpthread#include <signal.h>
#include <stdio.h>
void exported_func()
{
printf("Address of pthread_sigmask: %p\n", pthread_sigmask);
}Output of readelf -Wa libshared.so | grep -Ei "pthread_sigmask|GLIBC.*Version" -1
0000000000002610 0000000100000006 R_X86_64_GLOB_DAT 0000000000000000 __gmon_start__ + 0
0000000000002618 0000000200000006 R_X86_64_GLOB_DAT 0000000000000000 pthread_sigmask@GLIBC_2.2.5 + 0
--
1: 0000000000000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
2: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask@GLIBC_2.2.5 (2)
3: 0000000000000000 0 FUNC GLOBAL DEFAULT UND printf@GLIBC_2.2.5 (2)
--
6: 0000000000001430 24 FUNC GLOBAL DEFAULT 12 exported_func
7: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask
8: 0000000000000000 0 FUNC GLOBAL DEFAULT UND printf
-- .gnu.version_r
000000: Version: 1 File: libc.so.6 Cnt: 1
0x0010: Name: GLIBC_2.2.5 Flags: none Version: 2
It seems that zig maps pthread_sigmask to libc library in .gnu.version_r section, but this symbol is still in libpthread in glibc 2.19. I assume that this fns.txt file is used to map symbols to specific libraries, because once I change this line pthread_sigmask c to pthread_sigmask pthread then zig cc correctly maps pthread_sigmask to libpthread and relocation error is gone:
0000000000002630 0000000100000006 R_X86_64_GLOB_DAT 0000000000000000 __gmon_start__ + 0
0000000000002638 0000000200000006 R_X86_64_GLOB_DAT 0000000000000000 pthread_sigmask@GLIBC_2.2.5 + 0
--
1: 0000000000000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
2: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask@GLIBC_2.2.5 (2)
3: 0000000000000000 0 FUNC GLOBAL DEFAULT UND printf@GLIBC_2.2.5 (3)
--
6: 0000000000001450 24 FUNC GLOBAL DEFAULT 12 exported_func
7: 0000000000000000 0 FUNC GLOBAL DEFAULT UND pthread_sigmask
8: 0000000000000000 0 FUNC GLOBAL DEFAULT UND printf
--
000000: Version: 1 File: libpthread.so.0 Cnt: 1
0x0020: Name: GLIBC_2.2.5 Flags: none Version: 2
0x0010: Version: 1 File: libc.so.6 Cnt: 1
0x0030: Name: GLIBC_2.2.5 Flags: none Version: 3
I assume that this edge case where a symbol can move between libraries might be overlooked and would need to be fixed by either having a separate fns.txt file for each glibc version or by introducing some versioning where there might be 2 lines for symbols like pthread_sigmask with something like pthread_sigmask pthread@2.31 where @2.31 is the last version where symbol is in that library. So when choosing specific glibc target version, correct symbol library mapping would be used.
@mjonaitis1 thanks for looking into this. Your suggested solution seems reasonable to me.