Hello, I'm attempting to run cross-compiled programs with qemu-ppc. Basic statically-linked programs work perfectly. However, if I attempt to run non-static programs or threaded programs, or if I attempt to call clone() with the CLONE_VM flag set, I get an invalid data memory access.
Threaded programs get an error when calling pthread_create, with an invalid data memory access at 0x00000018. A simple test program using clone with CLONE_VM gets an invalid data memory access at 0x00000008. Non-static programs get an invalid data memory access at various addresses around 0x0de00000, before ever reaching main(). I've attached the test program I used to test clone(), as it seems to be the simplest test case which fails. I'd be happy to help with debugging this problem; if you need any more information or you'd like me to run additional tests, please let me know. I've tested both the Debian-packaged qemu-7.0 and an unmodified qemu-0.7.2 from qemu.org ; with the latter, all of the above tests still fail, but I get a few more error messages along the lines of "Invalid segfault errno (a000000)" and "qemu: uncaught target signal 11 (Segmentation fault) - exiting". In addition, when I run the hello-clone program under qemu-7.2, the parent also experiences an "invalid data memory access" error and segfaults, whereas with 7.0 the parent ran fine and only the child had an "invalid data memory access" error and segfault. Some background: I'm a member of the Portland State Aerospace Society, and we're in the process of switching our rocket's flight computer (which runs Debian GNU/Linux) over to PowerPC. I'm attempting to get our flight-control software to run under qemu-ppc so that I can test it under simulation; the flight-control software currently makes use of pthreads. - Josh Triplett
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <sys/types.h>
/* int i = 0; */
int thread_main(void *arg)
{
printf("child: Hello world!\n");
while(1) /* i++ */;
return 0;
}
unsigned long stack[8192];
int main()
{
int pid;
printf("About to clone: thread_main=%p\n", thread_main);
pid = clone(thread_main, stack+4096, CLONE_VM, NULL);
if(pid == -1)
{
perror("clone");
return 1;
}
printf("parent: clone successful; child pid is %d\n", pid);
printf("parent: sleeping a bit\n");
sleep(2);
/* printf("parent: value is %d\n", i); */
printf("parent: killing process\n");
kill(pid, SIGTERM);
return 0;
}
signature.asc
Description: OpenPGP digital signature
_______________________________________________ Qemu-devel mailing list Qemu-devel@nongnu.org http://lists.nongnu.org/mailman/listinfo/qemu-devel
