linux-kernel - Re: [PATCH] selftests: add binderfs selftests

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Message-ID: <20190116164219.GD5446@kroah.com>
Date:   Wed, 16 Jan 2019 17:42:20 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Christian Brauner <christian@...uner.io>
Cc:     tkjos@...roid.com, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, joel@...lfernandes.org,
        arve@...roid.com, maco@...roid.com, tkjos@...gle.com
Subject: Re: [PATCH] selftests: add binderfs selftests

On Wed, Jan 16, 2019 at 06:21:12PM +0200, Christian Brauner wrote:
> On January 16, 2019 5:54:50 PM GMT+02:00, Greg KH <gregkh@...uxfoundation.org> wrote:
> >On Wed, Jan 16, 2019 at 02:19:03PM +0100, Christian Brauner wrote:
> >> This adds the promised selftest for binderfs. It will verify the
> >following
> >> things:
> >> - binderfs mounting works
> >> - binder device allocation works
> >> - performing a binder ioctl() request through a binderfs device works
> >> - binder device removal works
> >> - binder-control removal fails
> >> - binderfs unmounting works
> >> 
> >> Cc: Todd Kjos <tkjos@...gle.com>
> >> Signed-off-by: Christian Brauner <christian.brauner@...ntu.com>
> >> ---
> >>  tools/testing/selftests/Makefile              |   1 +
> >>  .../selftests/filesystems/binderfs/.gitignore |   1 +
> >>  .../selftests/filesystems/binderfs/Makefile   |   6 +
> >>  .../filesystems/binderfs/binderfs_test.c      | 120
> >++++++++++++++++++
> >>  .../selftests/filesystems/binderfs/config     |   3 +
> >>  5 files changed, 131 insertions(+)
> >>  create mode 100644
> >tools/testing/selftests/filesystems/binderfs/.gitignore
> >>  create mode 100644
> >tools/testing/selftests/filesystems/binderfs/Makefile
> >>  create mode 100644
> >tools/testing/selftests/filesystems/binderfs/binderfs_test.c
> >>  create mode 100644
> >tools/testing/selftests/filesystems/binderfs/config
> >> 
> >> diff --git a/tools/testing/selftests/Makefile
> >b/tools/testing/selftests/Makefile
> >> index 1a2bd15c5b6e..400ee81a3043 100644
> >> --- a/tools/testing/selftests/Makefile
> >> +++ b/tools/testing/selftests/Makefile
> >> @@ -10,6 +10,7 @@ TARGETS += drivers/dma-buf
> >>  TARGETS += efivarfs
> >>  TARGETS += exec
> >>  TARGETS += filesystems
> >> +TARGETS += filesystems/binderfs
> >>  TARGETS += firmware
> >>  TARGETS += ftrace
> >>  TARGETS += futex
> >> diff --git a/tools/testing/selftests/filesystems/binderfs/.gitignore
> >b/tools/testing/selftests/filesystems/binderfs/.gitignore
> >> new file mode 100644
> >> index 000000000000..8a5d9bf63dd4
> >> --- /dev/null
> >> +++ b/tools/testing/selftests/filesystems/binderfs/.gitignore
> >> @@ -0,0 +1 @@
> >> +binderfs_test
> >> diff --git a/tools/testing/selftests/filesystems/binderfs/Makefile
> >b/tools/testing/selftests/filesystems/binderfs/Makefile
> >> new file mode 100644
> >> index 000000000000..58cb659b56b4
> >> --- /dev/null
> >> +++ b/tools/testing/selftests/filesystems/binderfs/Makefile
> >> @@ -0,0 +1,6 @@
> >> +# SPDX-License-Identifier: GPL-2.0
> >> +
> >> +CFLAGS += -I../../../../../usr/include/
> >> +TEST_GEN_PROGS := binderfs_test
> >> +
> >> +include ../../lib.mk
> >> diff --git
> >a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
> >b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
> >> new file mode 100644
> >> index 000000000000..ca4d9b616e84
> >> --- /dev/null
> >> +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
> >> @@ -0,0 +1,120 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +
> >> +#define _GNU_SOURCE
> >> +#include <errno.h>
> >> +#include <fcntl.h>
> >> +#include <sched.h>
> >> +#include <stdio.h>
> >> +#include <stdlib.h>
> >> +#include <string.h>
> >> +#include <sys/ioctl.h>
> >> +#include <sys/mount.h>
> >> +#include <sys/stat.h>
> >> +#include <sys/types.h>
> >> +#include <unistd.h>
> >> +#include <linux/android/binder.h>
> >> +#include <linux/android/binderfs.h>
> >> +#include "../../kselftest.h"
> >> +
> >> +int main(int argc, char *argv[])
> >> +{
> >> +	int fd, ret, saved_errno;
> >> +	size_t len;
> >> +	struct binderfs_device device = { 0 };
> >> +	struct binder_version version = { 0 };
> >> +
> >> +	ret = unshare(CLONE_NEWNS);
> >> +	if (ret < 0)
> >> +		ksft_exit_fail_msg("%s - Failed to unshare mount namespace\n",
> >> +				   strerror(errno));
> >> +
> >> +	ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
> >> +	if (ret < 0)
> >> +		ksft_exit_fail_msg("%s - Failed to mount / as private\n",
> >> +				   strerror(errno));
> >> +
> >> +	ret = mkdir("/dev/binderfs", 0755);
> >> +	if (ret < 0 && errno != EEXIST)
> >> +		ksft_exit_fail_msg(
> >> +			"%s - Failed to create binderfs mountpoint\n",
> >> +			strerror(errno));
> >> +
> >> +	ret = mount(NULL, "/dev/binderfs", "binder", 0, 0);
> >> +	if (ret < 0)
> >> +		ksft_exit_fail_msg("%s - Failed to mount binderfs\n",
> >> +				   strerror(errno));
> >
> >Can you check first to see if the kernel under test really even has
> >binderfs in it?  If not, you need to just
> 
> Hm, I thought that's what the "config" file was for?
> E.g. a conditional compile or is this just a hint to the
> user what's needed to run the test?

I do not know.  What happens if you try to run this test on a kernel
without that config option?  Does it not work as the framework correctly
detects this?

And new kernel self tests should cc: the ksefltest mailing list and the
maintainer of that subsystem so that they can review the test for things
like this.

thanks,

greg k-h