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

From: Michael Ellerman <mpe@ellerman.id.au>
To: Christian Brauner <christian@brauner.io>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Cc: linux-kernel@vger.kernel.org, arnd@arndb.de,
	linux-arch@vger.kernel.org, linux-alpha@vger.kernel.org,
	linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
	linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
	linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
	Vasily Gorbik <gor@linux.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [PATCH 1/2] arch: mark syscall number 435 reserved for clone3
Date: Fri, 19 Jul 2019 20:18:02 +1000	[thread overview]
Message-ID: <874l3i8h0l.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20190716130631.tohj4ub54md25dys@brauner.io>

Christian Brauner <christian@brauner.io> 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