[chrony-users] No packets transmitted when using Yocto 4.3.1

[Thomas Lange <thomas@xxxxxxxxxxxx>]

Hi,
when I cross compile Chrony for a 32bit ARM system using Yocto 4.3.1, no NTP
packets are transmitted.

cmsg_type is set to SO_TIMESTAMPING_NEW.
This is rejected by __sock_cmsg_send() in net/core/sock.c and no packet
is transmitted:

4.3.1
-----
clock_gettime64(CLOCK_REALTIME, {tv_sec=1702632790, tv_nsec=105009194}) = 0
sendmsg(5, {msg_name={sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("172.16.1.2")}, msg_namelen=16, msg_iov=[{iov_base="#\0\6 \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., iov_len=48}], msg_iovlen=1, msg_control=[{cmsg_len=16, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMPING_NEW, cmsg_data=???}], msg_controllen=16, msg_flags=0}, 0) = -1 EINVAL (Invalid argument)


When using Yocto 4.2.3, cmsg_type is set to SO_TIMESTAMPING_OLD.
This works fine:

4.2.3
-----
clock_gettime64(CLOCK_REALTIME, {tv_sec=1702632678, tv_nsec=601199243}) = 0
sendmsg(5, {msg_name={sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("172.16.1.2")}, msg_namelen=16, msg_iov=[{iov_base="#\0\6 \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., iov_len=48}], msg_iovlen=1, msg_control=[{cmsg_len=16, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMPING_OLD, cmsg_data=???}], msg_controllen=16, msg_flags=0}, 0) = 48


I think the 4.3.1 behavior is due to 64bit time now being default in Yocto:

arm-poky-linux-gnueabi-gcc  -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a9 -fstack-protector-strong  -O2 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 --sysroot=/opt/yocto/4.3.1/sysroots/cortexa9hf-neon-poky-linux-gnueabi -O2 -pipe -g -feliminate-unused-debug-types  -pthread  -c socket.c

which maps SO_TIMESTAMP to SO_TIMESTAMP_NEW.

I am currently using a kernel based on 5.15.100. I haven't tried a newer one yet
but looking at 6.7-rc5, the code in __sock_cmsg_send still doesn't support
SO_TIMESTAMPING_NEW.

Before I dig deeper, I want to check if this is a known issue already?

/Thomas

--
To unsubscribe email chrony-users-request@xxxxxxxxxxxxxxxxxxxx 
with "unsubscribe" in the subject.
For help email chrony-users-request@xxxxxxxxxxxxxxxxxxxx 
with "help" in the subject.
Trouble?  Email listmaster@xxxxxxxxxxxxxxxxxxxx.