Segmenation fault when a process resumed with checkpt exits

[Stanislav Syekirin]

Hi,

I'm experimenting with process checkpointing in DragonFly 6.2.1 and 
don't know how to exit a resumed process correclty. The man page for 
sys_checkpoint doesn't address the question, as far as I can see: the 
example loops forever and only exits if there is an error.

I have the following code (error handling omitted for brevity):

    #include <stdio.h>
    #include <stdlib.h>
    #include <fcntl.h>
    #include <unistd.h>
    #include <sys/checkpoint.h>

    void save(const char* filename)
    {
        int file = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666);
        sys_checkpoint(CKPT_FREEZE, file, -1, -1);
        close(file);
    }

    int main()
    {
        puts("a");
        save("a.ckpt");
        puts("b");
    }

This is the output I get:

% gcc test.c -o test -Wall -Wextra
% ./test
a
b
% checkpt -r a.ckpt
b
pid 1143 (test), uid 1001: exited on signal 11 (core dumped)
Segmentation fault (core dumped)

This is the backtrace I get with gdb test test.core:

#0  0x000000080040400f in __tls_get_addr () from /libexec/ld-elf.so.2
#1  0x000000080075648a in _thread_finalize () from /lib/libc.so.8
#2  0x0000000800756449 in exit () from /lib/libc.so.8
#3  0x00000000004007b3 in _start ()

Help would be appreciated.

Regards
Stanislav