On Thu, May 14, 2020 at 12:21:13PM +0200, John Paul Adrian Glaubitz wrote:
> On 5/14/20 12:19 PM, Christian Brauner wrote:
> > Scratch that. It's even worse. On ia64 it is _invalid_ to pass a NULL
> > stack. That's at least what the glibc assembly assumes:
> >
> > cmp.eq p6,p0=0,in0
> > cmp.eq p7,p0=0,in1
> > mov r8=EINVAL
> > mov out0=in3 /* Flags are first syscall argument. */
> > mov out1=in1 /* Stack address. */
> > (p6) br.cond.spnt.many __syscall_error /* no NULL function
> > pointers */
> > (p7) br.cond.spnt.many __syscall_error /* no NULL stack
> > pointers */
> > ;;
> > mov out2=in2 /* Stack size. */
> >
> > so newer systemd just works by accident on ia64 if at all correctly
> > afaict.
>
> Hmm, interesting. I really wasn't aware of that. Thanks for the heads-up.
>
> I'll ask Michael whether he can come up for a solution for that problem.
>
> Maybe that's also why systemd crashes.
Do you have a very minimalistic ia64 userspace preferably without systemd where
you could simply test. That should give us an idea whether things work:
#define _GNU_SOURCE
#include <sys/wait.h>
#include <sys/utsname.h>
#include <sched.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#define STACK_SIZE (8 * 1024 * 1024) /* standard stack size for threads in
glibc */
int main(int argc, char *argv[])
{
char *stack;
pid_t pid;
stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (stack == MAP_FAILED)
exit(EXIT_FAILURE);
/*
* Note that legacy clone() has different argument ordering on
* different architectures so this won't work everywhere.
*/
pid = syscall(189 /* __NR_clone2 */, SIGCHLD, stack, STACK_SIZE, NULL,
NULL);
if (pid < 0)
exit(EXIT_FAILURE);
if (pid == 0)
exit(EXIT_SUCCESS);
if (wait(NULL) != pid)
exit(EXIT_FAILURE);
exit(EXIT_SUCCESS);
}
