Android OS (Termux) _a.cxx_=`int main(int, const char **) {return 0;}`, `clang++ a.cxx`, `valgrind ./a.out` gives `Unrecognised instruction at address X`

[SwuduSusuwu]

Problem description

For almost all terminals which compile sources, valgrind has lots of uses. But with Termux, valgrind always outputs Unrecognized instruction at address X

What steps will reproduce the bug?

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~ $ cat a.cxx
int main(int, const char **) {
        return 0;
}

~ $ clang++ a.cxx
~ $ ./a.out
~ $ valgrind ./a.out
==8263== Memcheck, a memory error detector
==8263== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==8263== Using Valgrind-3.22.0 and LibVEX; rerun with -h for copyright info
==8263== Command: ./a.out
==8263==
ARM64 front end: load_store
disInstr(arm64): unhandled instruction 0x38BFC109
disInstr(arm64): 0011'1000 1011'1111 1100'0001 0000'1001
==8263== valgrind: Unrecognised instruction at address 0x4073170.
==8263==    at 0x4073170: __dl__Z26__libc_safe_arc4random_bufPvm (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x4078377: __dl___libc_init_main_thread_late (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x410665F: __dl__ZL29__linker_init_post_relocationR19KernelArgumentBlockR6soinfo (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x41065CB: __dl___linker_init (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x4048007: __dl__start (in /apex/com.android.runtime/bin/linker64)
==8263== Your program just tried to execute an instruction that Valgrind
==8263== did not recognise.  There are two possible reasons for this.
==8263== 1. Your program has a bug and erroneously jumped to a non-code
==8263==    location.  If you are running Memcheck and you just saw a
==8263==    warning about a bad jump, it's probably your program's fault.
==8263== 2. The instruction is legitimate but Valgrind doesn't handle it,
==8263==    i.e. it's Valgrind's fault.  If you think this is the case or
==8263==    you are not sure, please let us know and we'll try to fix it.
==8263== Either way, Valgrind will now raise a SIGILL signal which will
==8263== probably kill your program.
==8263==
==8263== Process terminating with default action of signal 4 (SIGILL)
==8263==  Illegal opcode at address 0x4073170
==8263==    at 0x4073170: __dl__Z26__libc_safe_arc4random_bufPvm (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x4078377: __dl___libc_init_main_thread_late (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x410665F: __dl__ZL29__linker_init_post_relocationR19KernelArgumentBlockR6soinfo (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x41065CB: __dl___linker_init (in /apex/com.android.runtime/bin/linker64)
==8263==    by 0x4048007: __dl__start (in /apex/com.android.runtime/bin/linker64)
==8263==
==8263== HEAP SUMMARY:
==8263==     in use at exit: 0 bytes in 0 blocks
==8263==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==8263==
==8263== All heap blocks were freed -- no leaks are possible
==8263==
==8263== For lists of detected and suppressed errors, rerun with: -s
==8263== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
Illegal instruction
~ $

[SwuduSusuwu]

~ $ valgrind /bin/ls
==14222== Memcheck, a memory error detector
==14222== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==14222== Using Valgrind-3.22.0 and LibVEX; rerun with -h for copyright info
==14222== Command: /bin/ls
==14222==
ARM64 front end: load_store
disInstr(arm64): unhandled instruction 0x38BFC109
disInstr(arm64): 0011'1000 1011'1111 1100'0001 0000'1001
==14222== valgrind: Unrecognised instruction at address 0x4073170.
==14222==    at 0x4073170: __dl__Z26__libc_safe_arc4random_bufPvm (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x4078377: __dl___libc_init_main_thread_late (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x410665F: __dl__ZL29__linker_init_post_relocationR19KernelArgumentBlockR6soinfo (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x41065CB: __dl___linker_init (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x4048007: __dl__start (in /apex/com.android.runtime/bin/linker64)
==14222== Your program just tried to execute an instruction that Valgrind
==14222== did not recognise.  There are two possible reasons for this.
==14222== 1. Your program has a bug and erroneously jumped to a non-code
==14222==    location.  If you are running Memcheck and you just saw a
==14222==    warning about a bad jump, it's probably your program's fault.
==14222== 2. The instruction is legitimate but Valgrind doesn't handle it,
==14222==    i.e. it's Valgrind's fault.  If you think this is the case or
==14222==    you are not sure, please let us know and we'll try to fix it.
==14222== Either way, Valgrind will now raise a SIGILL signal which will
==14222== probably kill your program.
==14222==
==14222== Process terminating with default action of signal 4 (SIGILL)
==14222==  Illegal opcode at address 0x4073170
==14222==    at 0x4073170: __dl__Z26__libc_safe_arc4random_bufPvm (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x4078377: __dl___libc_init_main_thread_late (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x410665F: __dl__ZL29__linker_init_post_relocationR19KernelArgumentBlockR6soinfo (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x41065CB: __dl___linker_init (in /apex/com.android.runtime/bin/linker64)
==14222==    by 0x4048007: __dl__start (in /apex/com.android.runtime/bin/linker64)
==14222==
==14222== HEAP SUMMARY:
==14222==     in use at exit: 0 bytes in 0 blocks
==14222==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==14222==
==14222== All heap blocks were freed -- no leaks are possible
==14222==
==14222== For lists of detected and suppressed errors, rerun with: -s
==14222== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
Illegal instruction
~ $

[SwuduSusuwu]

From cxx/ClassCns.cxx:posixExec

const int posixExec(const std::string &executable, const std::string &argsS, const std::string &envVarsS) {
#ifdef _POSIX_VERSION
    char *args[] = {
        const_cast<char *>(executable.c_str()),
        const_cast<char *>(argsS.c_str()),
        NULL
    };
    char *envVars[] = {
        const_cast<char *>(envVarsS.c_str()),
        NULL
    };
    return execve(args[0], args, envVars);
#endif /* def _POSIX_VERSION */
}

, to

const int posixExec(const std::string &executable, const std::string &argsS, const std::string &envVarsS) {
}

, fixes conversationCnsTestsThrows() + testsHarnesses():

~/SubStack $ ./make.sh
/* Dual licenses: choose "Creative Commons" or "Apache 2" (allows all uses) */
/data/data/com.termux/files/usr/bin/ctags
/data/data/com.termux/files/usr/bin/clang++
./~/SubStack $ ./a.out
cxx/Macros.hxx: pass
cxx/VirusAnalysis.hxx: pass
cxx/ConversationCns.hxx: pass
~/SubStack $

, but posixExec() is supposed to exist, so can not commit this.

[ivosh]

Dear @SwuduSusuwu please report the bug against the official Valgrind source code: https://valgrind.org/support/bug_reports.html

This repository (https://github.com/ivosh/valgrind/) is just a fork, several years old now.