2019-07-14 19:24:17

by Christian Brauner

[permalink] [raw]
Subject: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

A while ago Arnd made it possible to give new system calls the same
syscall number on all architectures (except alpha). To not break this
nice new feature let's mark 435 for clone3 as reserved on all
architectures that do not yet implement it.
Even if an architecture does not plan to implement it this ensures that
new system calls coming after clone3 will have the same number on all
architectures.

Signed-off-by: Christian Brauner <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/ia64/kernel/syscalls/syscall.tbl | 1 +
arch/m68k/kernel/syscalls/syscall.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
arch/parisc/kernel/syscalls/syscall.tbl | 1 +
arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
arch/s390/kernel/syscalls/syscall.tbl | 1 +
arch/sh/kernel/syscalls/syscall.tbl | 1 +
arch/sparc/kernel/syscalls/syscall.tbl | 1 +
11 files changed, 11 insertions(+)

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 1db9bbcfb84e..728fe028c02c 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -474,3 +474,4 @@
542 common fsmount sys_fsmount
543 common fspick sys_fspick
544 common pidfd_open sys_pidfd_open
+# 545 reserved for clone3
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index ecc44926737b..36d5faf4c86c 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -355,3 +355,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 9a3eb2558568..a88a285a0e5f 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -434,3 +434,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 97035e19ad03..c9c879ec9b6d 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -373,3 +373,4 @@
432 n32 fsmount sys_fsmount
433 n32 fspick sys_fspick
434 n32 pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index d7292722d3b0..bbce9159caa1 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -349,3 +349,4 @@
432 n64 fsmount sys_fsmount
433 n64 fspick sys_fspick
434 n64 pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index dba084c92f14..9653591428ec 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -422,3 +422,4 @@
432 o32 fsmount sys_fsmount
433 o32 fspick sys_fspick
434 o32 pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 5022b9e179c2..c7aadfef5386 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -431,3 +431,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index f2c3bda2d39f..3331749aab20 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -516,3 +516,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 6ebacfeaf853..a90d3e945445 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -437,3 +437,4 @@
432 common fsmount sys_fsmount sys_fsmount
433 common fspick sys_fspick sys_fspick
434 common pidfd_open sys_pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 834c9c7d79fa..b5ed26c4c005 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -437,3 +437,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index c58e71f21129..8c8cc7537fb2 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -480,3 +480,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
--
2.22.0


2019-07-15 13:57:45

by Christian Borntraeger

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

I think Vasily already has a clone3 patch for s390x with 435.


On 14.07.19 21:22, Christian Brauner wrote:
> A while ago Arnd made it possible to give new system calls the same
> syscall number on all architectures (except alpha). To not break this
> nice new feature let's mark 435 for clone3 as reserved on all
> architectures that do not yet implement it.
> Even if an architecture does not plan to implement it this ensures that
> new system calls coming after clone3 will have the same number on all
> architectures.
>
> Signed-off-by: Christian Brauner <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---
> arch/alpha/kernel/syscalls/syscall.tbl | 1 +
> arch/ia64/kernel/syscalls/syscall.tbl | 1 +
> arch/m68k/kernel/syscalls/syscall.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
> arch/parisc/kernel/syscalls/syscall.tbl | 1 +
> arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
> arch/s390/kernel/syscalls/syscall.tbl | 1 +
> arch/sh/kernel/syscalls/syscall.tbl | 1 +
> arch/sparc/kernel/syscalls/syscall.tbl | 1 +
> 11 files changed, 11 insertions(+)
>
> diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
> index 1db9bbcfb84e..728fe028c02c 100644
> --- a/arch/alpha/kernel/syscalls/syscall.tbl
> +++ b/arch/alpha/kernel/syscalls/syscall.tbl
> @@ -474,3 +474,4 @@
> 542 common fsmount sys_fsmount
> 543 common fspick sys_fspick
> 544 common pidfd_open sys_pidfd_open
> +# 545 reserved for clone3
> diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
> index ecc44926737b..36d5faf4c86c 100644
> --- a/arch/ia64/kernel/syscalls/syscall.tbl
> +++ b/arch/ia64/kernel/syscalls/syscall.tbl
> @@ -355,3 +355,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
> index 9a3eb2558568..a88a285a0e5f 100644
> --- a/arch/m68k/kernel/syscalls/syscall.tbl
> +++ b/arch/m68k/kernel/syscalls/syscall.tbl
> @@ -434,3 +434,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> index 97035e19ad03..c9c879ec9b6d 100644
> --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> @@ -373,3 +373,4 @@
> 432 n32 fsmount sys_fsmount
> 433 n32 fspick sys_fspick
> 434 n32 pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
> index d7292722d3b0..bbce9159caa1 100644
> --- a/arch/mips/kernel/syscalls/syscall_n64.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
> @@ -349,3 +349,4 @@
> 432 n64 fsmount sys_fsmount
> 433 n64 fspick sys_fspick
> 434 n64 pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> index dba084c92f14..9653591428ec 100644
> --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> @@ -422,3 +422,4 @@
> 432 o32 fsmount sys_fsmount
> 433 o32 fspick sys_fspick
> 434 o32 pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
> index 5022b9e179c2..c7aadfef5386 100644
> --- a/arch/parisc/kernel/syscalls/syscall.tbl
> +++ b/arch/parisc/kernel/syscalls/syscall.tbl
> @@ -431,3 +431,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> index f2c3bda2d39f..3331749aab20 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -516,3 +516,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
> index 6ebacfeaf853..a90d3e945445 100644
> --- a/arch/s390/kernel/syscalls/syscall.tbl
> +++ b/arch/s390/kernel/syscalls/syscall.tbl
> @@ -437,3 +437,4 @@
> 432 common fsmount sys_fsmount sys_fsmount
> 433 common fspick sys_fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
> index 834c9c7d79fa..b5ed26c4c005 100644
> --- a/arch/sh/kernel/syscalls/syscall.tbl
> +++ b/arch/sh/kernel/syscalls/syscall.tbl
> @@ -437,3 +437,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
> diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
> index c58e71f21129..8c8cc7537fb2 100644
> --- a/arch/sparc/kernel/syscalls/syscall.tbl
> +++ b/arch/sparc/kernel/syscalls/syscall.tbl
> @@ -480,3 +480,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +# 435 reserved for clone3
>

2019-07-15 14:56:40

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
> I think Vasily already has a clone3 patch for s390x with 435.

Excellent. I'll leave the # 435 reserved for clone3 on s390x in until
this patch has landed. It shouldn't be a merge conflict and if so it
should be trivial.

Christian

2019-07-16 13:07:49

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
> I think Vasily already has a clone3 patch for s390x with 435.

A quick follow-up on this. Helge and Michael have asked whether there
are any tests for clone3. Yes, there will be and I try to have them
ready by the end of the this or next week for review. In the meantime I
hope the following minimalistic test program that just verifies very
very basic functionality (It's not pretty.) will help you test:

#define _GNU_SOURCE
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <sched.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>

#ifndef CLONE_PIDFD
#define CLONE_PIDFD 0x00001000
#endif

#ifndef __NR_clone3
#define __NR_clone3 -1
#endif

static pid_t sys_clone3(struct clone_args *args)
{
return syscall(__NR_clone3, args, sizeof(struct clone_args));
}

static int wait_for_pid(pid_t pid)
{
int status, ret;

again:
ret = waitpid(pid, &status, 0);
if (ret == -1) {
if (errno == EINTR)
goto again;

return -1;
}

if (ret != pid)
goto again;

if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
return -1;

return 0;
}

#define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr)))

int main(int argc, char *argv[])
{
int pidfd = -1;
pid_t parent_tid = -1, pid = -1;
struct clone_args args = {0};

args.parent_tid = ptr_to_u64(&parent_tid); /* CLONE_PARENT_SETTID */
args.pidfd = ptr_to_u64(&pidfd); /* CLONE_PIDFD */
args.flags = CLONE_PIDFD | CLONE_PARENT_SETTID;
args.exit_signal = SIGCHLD;

pid = sys_clone3(&args);
if (pid < 0) {
fprintf(stderr, "%s - Failed to create new process\n", strerror(errno));
exit(EXIT_FAILURE);
}

if (pid == 0) {
printf("Child process with pid %d\n", getpid());
exit(EXIT_SUCCESS);
}

printf("Parent process received child's pid %d as return value\n", pid);
printf("Parent process received child's pidfd %d\n", *(int *)args.pidfd);
printf("Parent process received child's pid %d as return argument\n",
*(pid_t *)args.parent_tid);

if (wait_for_pid(pid))
exit(EXIT_FAILURE);

if (pid != *(pid_t *)args.parent_tid)
exit(EXIT_FAILURE);

close(pidfd);

return 0;
}

2019-07-16 18:57:14

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

On Tue, Jul 16, 2019 at 08:53:10PM +0200, Sven Schnelle wrote:
> Hi,
>
> [Adding Helge to CC list]
>
> On Tue, Jul 16, 2019 at 03:06:33PM +0200, Christian Brauner wrote:
> > On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
> > > I think Vasily already has a clone3 patch for s390x with 435.
> >
> > A quick follow-up on this. Helge and Michael have asked whether there
> > are any tests for clone3. Yes, there will be and I try to have them
> > ready by the end of the this or next week for review. In the meantime I
> > hope the following minimalistic test program that just verifies very
> > very basic functionality (It's not pretty.) will help you test:
> > [..]
>
> On PA-RISC this seems to work fine with Helge's patch to wire up the
> clone3 syscall.

I think I already responded to Helge before and yes, I think that parisc
doesn't do anything special for fork, vfork, clone, and by extension
also probably doesn't need to for clone3.
It should only be a problem for arches that require mucking explicitly
with arguments of clone-like syscalls.
In any case, I saw Helge's patch and I think I might've missed to add an
Acked-by but feel free to add it.

Thanks for testing it and sorry that I couldn't test!
Christian

2019-07-16 19:31:20

by Sven Schnelle

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

Hi,

[Adding Helge to CC list]

On Tue, Jul 16, 2019 at 03:06:33PM +0200, Christian Brauner wrote:
> On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
> > I think Vasily already has a clone3 patch for s390x with 435.
>
> A quick follow-up on this. Helge and Michael have asked whether there
> are any tests for clone3. Yes, there will be and I try to have them
> ready by the end of the this or next week for review. In the meantime I
> hope the following minimalistic test program that just verifies very
> very basic functionality (It's not pretty.) will help you test:
> [..]

On PA-RISC this seems to work fine with Helge's patch to wire up the
clone3 syscall.

root@c3750:/# clonetest
Parent process received child's pid 84 as return value
Parent process received child's pidfd 3
Parent process received child's pid 84 as return argument
Child process with pid 84
root@c3750:/# echo $?
0

Regards
Sven

2019-07-16 20:14:52

by Helge Deller

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

On 16.07.19 20:55, Christian Brauner wrote:
> On Tue, Jul 16, 2019 at 08:53:10PM +0200, Sven Schnelle wrote:
>> Hi,
>>
>> [Adding Helge to CC list]
>>
>> On Tue, Jul 16, 2019 at 03:06:33PM +0200, Christian Brauner wrote:
>>> On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
>>>> I think Vasily already has a clone3 patch for s390x with 435.
>>>
>>> A quick follow-up on this. Helge and Michael have asked whether there
>>> are any tests for clone3. Yes, there will be and I try to have them
>>> ready by the end of the this or next week for review. In the meantime I
>>> hope the following minimalistic test program that just verifies very
>>> very basic functionality (It's not pretty.) will help you test:
>>> [..]
>>
>> On PA-RISC this seems to work fine with Helge's patch to wire up the
>> clone3 syscall.
>
> [...]
> In any case, I saw Helge's patch and I think I might've missed to add an
> Acked-by but feel free to add it.

Thanks!
I've added the patch to the parisc-linux for-next tree.

Helge

2019-07-19 10:19:38

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

Christian Brauner <[email protected]> writes:
> On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
>> I think Vasily already has a clone3 patch for s390x with 435.
>
> A quick follow-up on this. Helge and Michael have asked whether there
> are any tests for clone3. Yes, there will be and I try to have them
> ready by the end of the this or next week for review. In the meantime I
> hope the following minimalistic test program that just verifies very
> very basic functionality (It's not pretty.) will help you test:

Hi Christian,

Thanks for the test.

This actually oopses on powerpc, it hits the BUG_ON in CHECK_FULL_REGS
in process.c around line 1633:

} else {
/* user thread */
struct pt_regs *regs = current_pt_regs();
CHECK_FULL_REGS(regs);
*childregs = *regs;
if (usp)


So I'll have to dig into how we fix that before we wire up clone3.

Turns out testing is good! :)

cheers

2019-07-19 10:25:50

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

On Fri, Jul 19, 2019 at 08:18:02PM +1000, Michael Ellerman wrote:
> Christian Brauner <[email protected]> writes:
> > On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
> >> I think Vasily already has a clone3 patch for s390x with 435.
> >
> > A quick follow-up on this. Helge and Michael have asked whether there
> > are any tests for clone3. Yes, there will be and I try to have them
> > ready by the end of the this or next week for review. In the meantime I
> > hope the following minimalistic test program that just verifies very
> > very basic functionality (It's not pretty.) will help you test:
>
> Hi Christian,
>
> Thanks for the test.
>
> This actually oopses on powerpc, it hits the BUG_ON in CHECK_FULL_REGS
> in process.c around line 1633:
>
> } else {
> /* user thread */
> struct pt_regs *regs = current_pt_regs();
> CHECK_FULL_REGS(regs);
> *childregs = *regs;
> if (usp)
>
>
> So I'll have to dig into how we fix that before we wire up clone3.
>
> Turns out testing is good! :)

Indeed. I have a test-suite for clone3 in mind and I hope to have it
ready by the end of next week. It's just always the finding the time
part that is annoying. :)

Thanks for digging into this, Michael!
Christian

2019-07-19 11:20:15

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

Christian Brauner <[email protected]> writes:
> On Fri, Jul 19, 2019 at 08:18:02PM +1000, Michael Ellerman wrote:
>> Christian Brauner <[email protected]> writes:
>> > On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
>> >> I think Vasily already has a clone3 patch for s390x with 435.
>> >
>> > A quick follow-up on this. Helge and Michael have asked whether there
>> > are any tests for clone3. Yes, there will be and I try to have them
>> > ready by the end of the this or next week for review. In the meantime I
>> > hope the following minimalistic test program that just verifies very
>> > very basic functionality (It's not pretty.) will help you test:
>>
>> Hi Christian,
>>
>> Thanks for the test.
>>
>> This actually oopses on powerpc, it hits the BUG_ON in CHECK_FULL_REGS
>> in process.c around line 1633:
>>
>> } else {
>> /* user thread */
>> struct pt_regs *regs = current_pt_regs();
>> CHECK_FULL_REGS(regs);
>> *childregs = *regs;
>> if (usp)
>>
>>
>> So I'll have to dig into how we fix that before we wire up clone3.
>>
>> Turns out testing is good! :)
>
> Indeed. I have a test-suite for clone3 in mind and I hope to have it
> ready by the end of next week. It's just always the finding the time
> part that is annoying. :)

I know the feeling!

> Thanks for digging into this, Michael!

No worries, happy to help where I can.

In the intervening five minutes I remembered how we handle this, we just
need a little wrapper to save the non-volatile regs:

_GLOBAL(ppc_clone3)
bl save_nvgprs
bl sys_clone3
b .Lsyscall_exit


A while back I meant to make it generate those automatically based on a
flag in the syscall.tbl but of course haven't got around to it :)

So with the above it seems all good:

$ ./clone3 ; echo $?
Parent process received child's pid 4204 as return value
Parent process received child's pidfd 3
Parent process received child's pid 4204 as return argument
Child process with pid 4204
0

I'll send a patch to wire it up on Monday.

cheers

2019-07-19 13:15:29

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3

On Fri, Jul 19, 2019 at 09:13:16PM +1000, Michael Ellerman wrote:
> Christian Brauner <[email protected]> writes:
> > On Fri, Jul 19, 2019 at 08:18:02PM +1000, Michael Ellerman wrote:
> >> Christian Brauner <[email protected]> writes:
> >> > On Mon, Jul 15, 2019 at 03:56:04PM +0200, Christian Borntraeger wrote:
> >> >> I think Vasily already has a clone3 patch for s390x with 435.
> >> >
> >> > A quick follow-up on this. Helge and Michael have asked whether there
> >> > are any tests for clone3. Yes, there will be and I try to have them
> >> > ready by the end of the this or next week for review. In the meantime I
> >> > hope the following minimalistic test program that just verifies very
> >> > very basic functionality (It's not pretty.) will help you test:
> >>
> >> Hi Christian,
> >>
> >> Thanks for the test.
> >>
> >> This actually oopses on powerpc, it hits the BUG_ON in CHECK_FULL_REGS
> >> in process.c around line 1633:
> >>
> >> } else {
> >> /* user thread */
> >> struct pt_regs *regs = current_pt_regs();
> >> CHECK_FULL_REGS(regs);
> >> *childregs = *regs;
> >> if (usp)
> >>
> >>
> >> So I'll have to dig into how we fix that before we wire up clone3.
> >>
> >> Turns out testing is good! :)
> >
> > Indeed. I have a test-suite for clone3 in mind and I hope to have it
> > ready by the end of next week. It's just always the finding the time
> > part that is annoying. :)
>
> I know the feeling!
>
> > Thanks for digging into this, Michael!
>
> No worries, happy to help where I can.
>
> In the intervening five minutes I remembered how we handle this, we just
> need a little wrapper to save the non-volatile regs:
>
> _GLOBAL(ppc_clone3)
> bl save_nvgprs
> bl sys_clone3
> b .Lsyscall_exit

Sounds good.

>
>
> A while back I meant to make it generate those automatically based on a
> flag in the syscall.tbl but of course haven't got around to it :)
>
> So with the above it seems all good:
>
> $ ./clone3 ; echo $?
> Parent process received child's pid 4204 as return value
> Parent process received child's pidfd 3
> Parent process received child's pid 4204 as return argument
> Child process with pid 4204
> 0
>
> I'll send a patch to wire it up on Monday.

Excellent! Thank you!
Christian