Re: [PATCH 1/2] selftests/filesystems: devpts_pts included wrong header

From: Christian Brauner
Date: Wed May 02 2018 - 10:05:27 EST

On Wed, Apr 18, 2018 at 09:52:55AM +0200, Anders Roxell wrote:
> We were picking up the wrong header should use asm/ioctls.h form the kernel
> and not the header from the system (sys/ioctl.h). In the current code we
> added the correct include and we added the kernel headers path to the CFLAGS.
>
> Fixes: ce290a19609d ("selftests: add devpts selftests")
> Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
> ---

Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>

Patch looks good to me.

I'm going to look into the ioctl() error.

Thanks!
Christian

>
> Hi,
>
> I've been running devpts_pts on a mainline kernel (4.16+git0+60cc43fc88) and



> the verify_invalid_ptmx_bind_mount() test failes with this failure:
>
> root@intel-core2-32:~# ./devpts_pts
> Failed to perform TIOCGPTPEER ioctl
>
> However, I'm still confused why I'm not able to get the test to pass. Strace
> showes that -ENOENT return in the TIOCGPTPEER implementation in the
> kernel. I think the -ENOENT gets returned from this path
> devpts_mntget()->devpts_ptmx_path->path_pts().
>
> See the strace issue below:
> root@intel-core2-32:~# strace ./devpts_pts
> execve("./devpts_pts", ["./devpts_pts"], [/* 17 vars */]) = 0
> brk(NULL) = 0x5634e0092000
> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f459d338000
> access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
> open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
> fstat(3, {st_mode=S_IFREG|0644, st_size=16726, ...}) = 0
> mmap(NULL, 16726, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f459d333000
> close(3) = 0
> open("/lib/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\3\2\0\0\0\0\0"..., 832) = 832
> fstat(3, {st_mode=S_IFREG|0755, st_size=1681056, ...}) = 0
> mmap(NULL, 3787168, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f459cd7b000
> mprotect(0x7f459cf0f000, 2093056, PROT_NONE) = 0
> mmap(0x7f459d10e000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x193000) = 0x7f459d10e000
> mmap(0x7f459d114000, 14752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f459d114000
> close(3) = 0
> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f459d331000
> arch_prctl(ARCH_SET_FS, 0x7f459d331700) = 0
> mprotect(0x7f459d10e000, 16384, PROT_READ) = 0
> mprotect(0x5634debe3000, 4096, PROT_READ) = 0
> mprotect(0x7f459d33a000, 4096, PROT_READ) = 0
> munmap(0x7f459d333000, 16726) = 0
> ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
> unshare(CLONE_NEWNS) = 0
> mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL) = 0
> mount("/dev/pts/ptmx", "/dev/ptmx", NULL, MS_BIND, NULL) = 0
> open("/dev/ptmx", O_RDWR|O_NOCTTY|O_CLOEXEC) = 3
> ioctl(3, TIOCSPTLCK, [0]) = 0
> ioctl(3, _IOC(0, 0x54, 0x41, 0x00), 0x80102) = 4
> clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f459d3319d0) = 4377
> wait4(4377, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 4377
> --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=4377, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
> close(3) = 0
> close(4) = 0
> getpid() = 4376
> open("/tmp/devpts_ptmx_Z6aEvy", O_RDWR|O_CREAT|O_EXCL, 0600) = 3
> mount("/dev/pts/ptmx", "/tmp/devpts_ptmx_Z6aEvy", NULL, MS_BIND, NULL) = 0
> close(3) = 0
> open("/tmp/devpts_ptmx_Z6aEvy", O_RDWR|O_NOCTTY|O_CLOEXEC) = 3
> ioctl(3, TIOCSPTLCK, [0]) = 0
> ioctl(3, _IOC(0, 0x54, 0x41, 0x00), 0x80102) = -1 ENOENT (No such file or directory)
> write(2, "Failed to perform TIOCGPTPEER io"..., 36Failed to perform TIOCGPTPEER ioctl
> ) = 36
> close(3) = 0
> umount2("/dev/pts", 0) = 0
> umount2("/dev/ptmx", 0) = 0
> mkdir("/tmp/devpts_fs_w22bR6", 0700) = 0
> mount("devpts", "/tmp/devpts_fs_w22bR6", "devpts", MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=0"...) = 0
> open("/tmp/devpts_fs_w22bR6/ptmx", O_RDWR|O_NOCTTY|O_CLOEXEC) = 3
> ioctl(3, TIOCSPTLCK, [0]) = 0
> ioctl(3, _IOC(0, 0x54, 0x41, 0x00), 0x80102) = 4
> clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f459d3319d0) = 4378
> wait4(4378, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 4378
> --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=4378, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
> close(3) = 0
> close(4) = 0
> unlink("/tmp/devpts_fs_w22bR6") = -1 EISDIR (Is a directory)
> exit_group(0) = ?
> +++ exited with 0 +++
> root@intel-core2-32:~#
>
> tools/testing/selftests/filesystems/Makefile | 1 +
> tools/testing/selftests/filesystems/devpts_pts.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/filesystems/Makefile b/tools/testing/selftests/filesystems/Makefile
> index 4e6d09fb166f..427a401aae5c 100644
> --- a/tools/testing/selftests/filesystems/Makefile
> +++ b/tools/testing/selftests/filesystems/Makefile
> @@ -1,5 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0
> TEST_PROGS := dnotify_test devpts_pts
> +CFLAGS += -I../../../../usr/include/
> all: $(TEST_PROGS)
>
> include ../lib.mk
> diff --git a/tools/testing/selftests/filesystems/devpts_pts.c b/tools/testing/selftests/filesystems/devpts_pts.c
> index b9055e974289..79420b9d00c7 100644
> --- a/tools/testing/selftests/filesystems/devpts_pts.c
> +++ b/tools/testing/selftests/filesystems/devpts_pts.c
> @@ -8,7 +8,7 @@
> #include <stdlib.h>
> #include <string.h>
> #include <unistd.h>
> -#include <sys/ioctl.h>
> +#include <asm/ioctls.h>
> #include <sys/mount.h>
> #include <sys/wait.h>
>
> --
> 2.11.0
>