[CRIU] [PATCH] s390: Prevent GOT relocations
Adrian Reber
areber at redhat.com
Tue Jul 18 18:22:20 MSK 2017
On Mon, Jul 17, 2017 at 08:44:30PM +0200, Michael Holzheu wrote:
> Am Mon, 17 Jul 2017 19:45:36 +0200
> schrieb Adrian Reber <areber at redhat.com>:
>
> > On Mon, Jul 17, 2017 at 07:21:21PM +0200, Michael Holzheu wrote:
> > > Am Mon, 17 Jul 2017 10:07:23 +0200
> > > schrieb Adrian Reber <areber at redhat.com>:
> > >
> > > > On Fri, Jul 14, 2017 at 02:56:26PM +0200, Michael Holzheu wrote:
> > > > > Am Fri, 14 Jul 2017 14:08:31 +0200
> > > > > schrieb Adrian Reber <areber at redhat.com>:
> > > > >
> > > > > > Thanks for the patch. I tried it on my s390 test system and I get the
> > > > > > following error now:
> > > > >
> > > > > Ok, fine - at least we don't see the compiler error any more.
> > > > >
> > > > > >
> > > > > > (00.002625) f15 0000000000000000
> > > > > > (00.002626) No VXRS
> > > > > > (00.002628) Putting tsock into pid 24
> > > > > > (00.002639) ptrace_set_regs: pid=24
> > > > > > (00.002656) Error (compel/src/lib/infect.c:633): Unable to connect a transport socket: Function not implemented
> > > > > > (00.002665) Error (compel/src/lib/infect.c:559): Can't inject syscall blob (pid: 24)
> > > > > > (00.002667) Error (compel/src/lib/infect.c:1312): munmap for remote map 0x3fffd5c5000, 53248 returned 4398002229248
> > > > > > (00.002669) Error (criu/cr-dump.c:1362): Can't infect (pid: 24) with parasite
> > > > > > (00.002720) Unlock network
> > > > > > (00.002735) Unfreezing tasks into 1
> > > > > > (00.002737) Unseizing 24 into 1
> > > > > > (00.002740) Error (compel/src/lib/infect.c:341): Unable to detach from 24: No such process
> > > > > > (00.002745) Unseizing 25 into 1
> > > > > > (00.002754) Error (criu/cr-dump.c:1800): Dumping FAILED.
> > > > >
> > > > > I think the problem is not related to the patch.
> > > > > Could you send me the full log?
> > > >
> > > > https://lisas.de/~adrian/dump-log.s390
> > >
> > > I assume that the target process "somehow" dies very early when
> > > the parasite code is started:
> > >
> > > compel/src/lib/infect.c:
> > >
> > > 627 if (parasite_run(pid, PTRACE_CONT, ctl->parasite_ip, ctl->rstack, ®s, &ctl->orig))
> > > 628 goto err;
> > >
> > > Here the __export_parasite_head_start() function is executed in the target
> > > process. This function then calls the parasite_service() function with
> > > the PARASITE_CMD_INIT_DAEMON command:
> > >
> > > compel/arch/s390/plugins/std/parasite-head.S:
> > >
> > > ENTRY(__export_parasite_head_start)
> > > larl %r14,__export_parasite_cmd
> > > llgf %r2,0(%r14)
> > > larl %r3,__export_parasite_args
> > > brasl %r14,parasite_service
> > > .long 0x00010001 /* S390_BREAKPOINT_U16: Generates SIGTRAP */
> > > __export_parasite_cmd:
> > > .long 0
> > >
> > > Perhaps you could manually try the following:
> > >
> > > 1) Run sleep program:
> > >
> > > # ulimit -c unlimited
> > > # sleep 10000
> > > [1] 8532
> > >
> > > 2) Checkpoint program
> > >
> > > # mkdir ~/dump
> > > # criu/criu dump -t 8532 --shell-job -D ~/dump
> > >
> > > 3) Check if we got a core dump for the sleep process
> >
> > No, I still get same error as before:
> >
> > (00.056660) Error (compel/src/lib/infect.c:633): Unable to connect a transport socket: Function not implemented
> > (00.056707) Error (compel/src/lib/infect.c:559): Can't inject syscall blob (pid: 1851)
> > (00.056721) Error (compel/src/lib/infect.c:1312): munmap for remote map 0x3fff6f49000, 466944 returned 4397894766592
> > (00.056733) Error (criu/cr-dump.c:1362): Can't infect (pid: 1851) with parasite
> >
> >
> > > Unfortunately I currently can't reproduce this on my RHEL7.4 kernel 3.10.0-685.el7.s390x
> > > because of a different problem:
> > >
> > > ~/criu # criu/criu dump -t 14545 --shell-job -D ~/dump/
> > > Error (criu/proc_parse.c:2654): Can't open 14545/task/14545/children on procfs: No such file or directory
> > > Error (criu/cr-dump.c:1800): Dumping FAILED.
> > >
> > > ~/criu # ls /proc/14545/task/14545/children
> > > ls: cannot access /proc/14545/task/14545/children: No such file or directory
> > >
> > > I assmue the problem is that my kernel has not enabled CONFIG_CHECKPOINT_RESTORE.
> >
> > I can provide you a test kernel (off-list). There is always the chance
> > that I am still missing important patches in my kernel.
>
> After enabling the memfd_create() syscall I found the following
> spot that failed in compel/plugins/std/infect.c:
>
> 138 static noinline __used int parasite_init_daemon(void *data)
> 139 {
> 140 struct parasite_init_args *args = data;
> 141 int ret;
> 142
> 143 args->sigreturn_addr = (uint64_t)(uintptr_t)fini_sigreturn;
> 144 sigframe = (void*)(uintptr_t)args->sigframe;
> 145
> 146 ret = tsock = sys_socket(PF_UNIX, SOCK_SEQPACKET, 0);
>
> Here we get ret = ENOSYS (-38)
>
> 147 if (tsock < 0) {
> 148 pr_err("Can't create socket: %d\n", tsock);
> 149 goto err;
> 150 }
> ...
> 172 err:
> 173 futex_set_and_wake(&args->daemon_connected, ret);
>
> Here we set daemon_connected = -38 ...
>
> 174 fini();
> 175 BUG();
> 176
> 177 return -1;
>
>
> ... which fits to the error message created in compel/src/lib/infect.c:
>
> 631 if (futex_get(&args->daemon_connected) != 1) {
> 632 errno = -(int)futex_get(&args->daemon_connected);
>
> Here we set errno = 38
>
> 633 pr_perror("Unable to connect a transport socket");
> 634 goto err;
> 635 }
>
> So looks like you have to wire sys_socket() for RHEL7?
Thanks for helping to figure this out. It was not only sys_socket().
Basically all syscalls from
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=977108f89c989b1eeb5c8d938e1e71913391eb5f
which were present in
compel/arch/s390/plugins/std/syscalls/syscall-s390.tbl had to be added
to the kernel. Now zdtm seems to be quite happy:
$ ./zdtm.py run -a -f h --keep-going -x zdtm/static/s390x_mmap_high
[...]
################### 1 TEST(S) FAILED (TOTAL 315/SKIPPED 115) ###################
* zdtm/static/stopped(h)
##################################### FAIL #####################################
I have to excldue zdtm/static/s390x_mmap_high as that test case just
hangs. zdtm says ==== ALARM ==== and then a process list.
Adrian
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