Hi,
On 16-03-15 18:12, David Herrmann wrote:
Hi Hans
On Mon, Mar 16, 2015 at 5:15 PM, Hans de Goede <hdego...@redhat.com> wrote:
Hi,
On some of the ARM boards I work on in my spare time I've
done "systemctl enable getty@ttyGS0.service" to get a getty
on the usb gadget serial port which I've configured on the
devices otg controller.
This serial port device node /dev/ttyGS0 shows up as soon
as the gadget serial port driver loads, but is only usable
when I plug in a the mini B end of a mini B -> A usb cable
where the A end is plugged into an active usb host.
"ps aux" shows something peculiar here, when I do "ps aux"
before the cable is plugged in it shows "(agetty)" in
the args column of the output, when I then plug in the
cable the output changes to "/sbin/agetty --noclear ttyGS0 vt220"
note this is the same process, as before the cable was plugged,
I've a feeling that somehow the process is stuck halfway
exec or some such ... ??
We rename the process to "(<file>)" directly after fork(). So if it is
still "(agetty)", something blocks before we can exec(). Can you run
strace to figure out what call blocks?
strace -p<pid> says:
write(3, "\33[r\33[H\33[2J", 10
And then when I plug in the cable (the ") = 10" is the write finishing) :
) = 10
close(3) = 0
open("/dev/null", O_RDONLY|O_NOCTTY|O_LARGEFILE) = 3
dup2(3, 0) = 0
close(3) = 0
socket(PF_LOCAL, SOCK_STREAM, 0) = 3
connect(3, {sa_family=AF_LOCAL, sun_path="/run/systemd/journal/stdout"}, 29) = 0
shutdown(3, SHUT_RD) = 0
getsockopt(3, SOL_SOCKET, SO_SNDBUF, [163840], [4]) = 0
setsockopt(3, SOL_SOCKET, SO_SNDBUFFORCE, [8388608], 4) = 0
fstat64(3, {st_mode=S_IFSOCK|0777, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
_llseek(3, 0, 0xbee70fc8, SEEK_CUR) = -1 ESPIPE (Illegal seek)
write(3, "agetty\ngetty@ttyGS0.service\n30\n1"..., 39) = 39
munmap(0xb6e0f000, 4096) = 0
dup2(3, 1) = 1
close(3) = 0
dup2(1, 2) = 2
fstatat64(AT_FDCWD, "/sys/fs/cgroup/systemd", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/systemd/system.slice/system-getty.slice/getty@ttyGS0.service/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = 3
fcntl64(3, F_GETFL) = 0x20001 (flags O_WRONLY|O_LARGEFILE)
fstat64(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
write(3, "379\n", 4) = 4
close(3) = 0
munmap(0xb6e0f000, 4096) = 0
fstatat64(AT_FDCWD, "/sys/fs/cgroup/cpu", {st_mode=S_IFLNK|0777, st_size=11,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/cpu/system.slice/system-getty.slice/getty@ttyGS0.service/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/cpu", {st_mode=S_IFLNK|0777, st_size=11,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/cpu/system.slice/system-getty.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/cpu", {st_mode=S_IFLNK|0777, st_size=11,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/cpu/system.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = 3
fcntl64(3, F_GETFL) = 0x20001 (flags O_WRONLY|O_LARGEFILE)
fstat64(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
write(3, "379\n", 4) = 4
close(3) = 0
munmap(0xb6e0f000, 4096) = 0
fstatat64(AT_FDCWD, "/sys/fs/cgroup/cpuacct", {st_mode=S_IFLNK|0777,
st_size=11, ...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/cpuacct/system.slice/system-getty.slice/getty@ttyGS0.service/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/cpuacct", {st_mode=S_IFLNK|0777,
st_size=11, ...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/cpuacct/system.slice/system-getty.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/cpuacct", {st_mode=S_IFLNK|0777,
st_size=11, ...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/cpuacct/system.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = 3
fcntl64(3, F_GETFL) = 0x20001 (flags O_WRONLY|O_LARGEFILE)
fstat64(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
write(3, "379\n", 4) = 4
close(3) = 0
munmap(0xb6e0f000, 4096) = 0
fstatat64(AT_FDCWD, "/sys/fs/cgroup/blkio", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/blkio/system.slice/system-getty.slice/getty@ttyGS0.service/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/blkio", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/blkio/system.slice/system-getty.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/blkio", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/blkio/system.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = 3
fcntl64(3, F_GETFL) = 0x20001 (flags O_WRONLY|O_LARGEFILE)
fstat64(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
write(3, "379\n", 4) = 4
close(3) = 0
munmap(0xb6e0f000, 4096) = 0
fstatat64(AT_FDCWD, "/sys/fs/cgroup/memory", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/memory/system.slice/system-getty.slice/getty@ttyGS0.service/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/memory", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/memory/system.slice/system-getty.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/memory", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/memory/system.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = 3
fcntl64(3, F_GETFL) = 0x20001 (flags O_WRONLY|O_LARGEFILE)
fstat64(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
write(3, "379\n", 4) = 4
close(3) = 0
munmap(0xb6e0f000, 4096) = 0
fstatat64(AT_FDCWD, "/sys/fs/cgroup/devices", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/devices/system.slice/system-getty.slice/getty@ttyGS0.service/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
fstatat64(AT_FDCWD, "/sys/fs/cgroup/devices", {st_mode=S_IFDIR|0555, st_size=0,
...}, AT_SYMLINK_NOFOLLOW) = 0
open("/sys/fs/cgroup/devices/system.slice/system-getty.slice/cgroup.procs",
O_WRONLY|O_NOCTTY|O_LARGEFILE|O_CLOEXEC) = 3
fcntl64(3, F_GETFL) = 0x20001 (flags O_WRONLY|O_LARGEFILE)
fstat64(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6e0f000
write(3, "379\n", 4) = 4
close(3) = 0
munmap(0xb6e0f000, 4096) = 0
getsid(0) = 379
clock_gettime(CLOCK_REALTIME, {1426530281, 697533469}) = 0
access("/var/run/utmpx", F_OK) = -1 ENOENT (No such file or directory)
open("/var/run/utmp", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
_llseek(3, 0, [0], SEEK_SET) = 0
access("/var/run/utmpx", F_OK) = -1 ENOENT (No such file or directory)
open("/var/run/utmp", O_RDWR|O_LARGEFILE|O_CLOEXEC) = 4
_llseek(3, 0, [0], SEEK_CUR) = 0
_llseek(4, 0, [0], SEEK_SET) = 0
dup2(4, 3) = 3
close(4) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, {it_interval={0, 0
And then a lot more cgroup, utmp, wtmp, etc. setup followed by a whole bunch
of ugetrlimit calls and then finally:
execve("/sbin/agetty", ["/sbin/agetty", "--noclear", "ttyGS0", "vt220"], [/* 16
vars */]) = 0
So your right that this is before executing agetty
Furthermore, what state is the process in?
Ss (ps aux state) looks like it blocks on a write to the not yet ready for use
tty.
Thanks
You're welcome and thanks for looking into this.
Regards,
Hans
David
If I plug in the cable I get a getty on the other end of
the usb gadget serial connection and everything more or less
works. I say more or less because it seems that part of
the welcome header from getty gets lost, and sometimes getty
acts as if it has received some garbage on its stdin. I mention
this because it may be related, but it may also very well be a
bug in the usb stack somewhere.
The problem which I have why I'm sending this mail is that
halt (-p) or reboot does not work when there is no usb cable
plugged into the otg connector.
"halt -p" just sits there for a long time, and then exits with
a dbus timeout error. If I plug in the cable while it is doing
this, then it continues and starts shutting down.
Regards,
Hans
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