[systemd-devel] systemctl hangs with 249.7 systemd in yocto Honister release

[Michal Koutný]

On Wed, Jan 04, 2023 at 04:51:22PM +0800, Heyi Guo <guoheyi at linux.alibaba.com> wrote:
> The issue happened again, but the /proc/1/stack and
> /proc/$pid_of_dbus-broker/stack are both empty on our platform.

(You reported previously the version was v249 (which is behind the last
two upstream versions, so it may be a good idea to raise the issue with
your distro.))

> I checked kernel config and confirmed that  CONFIG_STACKTRACE is enabled:
> 
> zcat /proc/config.gz | grep CONFIG_STACKTRACE
> CONFIG_STACKTRACE_SUPPORT=y
> # CONFIG_STACKTRACE_BUILD_ID is not set
> CONFIG_STACKTRACE=y
> 
> Is there any other config that is missing?

I don't think so (the file wouldn't be present otherwise).

If there are no kernel stacks, the tasks execute in userspace and given
the indefinite stuckage, they're likely looping somewhere (or you must
have been unlucky to miss a syscall), which should manifest in their CPU
consumption.

The userspace stack may be of interest then, e.g.
`gdb -ex "bt" --batch -p 1`

(for PID 1 and debuginfo for involved binaries must be present to obtain
useful info).

Michal
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