# Bad system call (core dumped) - mfsBSD



## Nutz (Jan 14, 2020)

Hi All,

I'm currently working on a mfsBSD build with FreeBSD-12.0 RELEASE and a custom kernel configuration.

Everything sounds good except when I want to use pkg command, I get the following error message :


```
r# pkg install test
Bad system call (core dumped)
```

I used "truss" to have more information about it, here the last part of the output:

```
openat(AT_FDCWD,"/",O_RDONLY|O_DIRECTORY|O_CLOEXEC,00) = 3 (0x3)
openat(AT_FDCWD,"/usr/bin/uname",O_RDONLY,00)     = 4 (0x4)
compat11.fstat(0,0x0)                 ERR#78 'Function not implemented'
SIGNAL 12 (SIGSYS) code=SI_KERNEL
process killed, signal = 12 (core dumped)
```

the system call compat11.fstat(0,0x0) seems to be the problem...
I'm building my custom kernel FreeBSD-12 from source on another server which is running under FreeBSD-11.1.
Do you think that's could be the problem ?


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## SirDice (Jan 14, 2020)

Nutz said:


> I'm building my custom kernel FreeBSD-12 from source


Your pkg(8) executable seems to originate from 11.x and your custom kernel lacks the COMPAT_FREEBSD11 option. Without that option there's no backwards compatibility. Either add COMPAT_FREEBSD11 or use a pkg(8) that's been built for 12.0.


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## Nutz (Jan 14, 2020)

errr...COMPAT_FREEBSD11..why i didnt see that...


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