Error record and replay target doesn't support syscall number 435

[Navin P]

Hi,
     I tried to record a program calling C++ threads and then did a
break on main , then record and continue it throws the error message
"record and replay target doesn't support syscall number 435" . What
should I do to support syscall number 435 ?

I was thinking of adding amd64_sys_clone3 = 435 to amd64-linux-tdep.h
In amd64-linux-tdep.c add  case amd64_sys_clone3: return gdb_sys_clone3;
In linux-record.h gdb_sys_clone3=541 in enum gdb_syscall
In linux-record.c case gdb_sys_clone3=break;


Is it necessary to do the record_mem_at_reg for clone3 ? Why isn't it
done for clone ?

Below is gdb log and after that is source code

gdb ./a.out
GNU gdb (Ubuntu 12.1-0ubuntu1~22.04) 12.1
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Reading symbols from ./a.out...
(gdb) b main
Breakpoint 1 at 0x134b: file race1.cpp, line 30.
(gdb) r
Starting program: /home/navin/cpp/a.out
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, main () at race1.cpp:30
30 int main(){
(gdb) record full
(gdb) c
Continuing.
Process record and replay target doesn't support syscall number 435
Process record: failed to record execution log.

Program stopped.
clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:60
60 ../sysdeps/unix/sysv/linux/x86_64/clone3.S: No such file or directory.
(gdb) shell uname -a
Linux Navin-acer-5740 5.15.0-91-generic #101-Ubuntu SMP Tue Nov 14
13:30:08 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
(gdb) shell cat /etc/lsb-release
DISTRIB_ID=LinuxMint
DISTRIB_RELEASE=21.2
DISTRIB_CODENAME=victoria
DISTRIB_DESCRIPTION="Linux Mint 21.2 Victoria"
(gdb)


Source Code

#include<bits/stdc++.h>
#include<thread>
using namespace std;

int g=0;
int *p=&g;
bool run=true;

void t1()
{
while(run)
{
g++;
if(g==16)
   p=nullptr;

}
}

void t2()
{
int z;
while(run)
{
g--;
z=*p+1;
}
}

int main(){
thread x1{t1};
thread x2{t2};
sleep(5);
run=false;
x1.join();
x2.join();
cout <<g<<endl;
}



Regards,
Navin