[lttng-dev] lttng-tools-2.10.6: Spawning consumerd failed

[Jonathan Rajotte-Julien]

Hi,

On Tue, May 14, 2019 at 03:20:31PM +0300, Zvi Vered wrote:
> Hello,
> 
> I ran the following command on the target (where my kernel is running):
> 
> ~ # ./lttng create my-kernel-session --output=/tmp/my-kernel-trace
> 
> and then:
> 
> 
> ~ # ./lttng enable-event --kernel --syscall open,close
> 
> and got:
> 
> Error: Spawning consumerd failed
> Error: Event open: Kernel consumer start failed (channel channel0,
> session my-kernel-session)
> PERROR - 00:25:59.397308194 [1930/1930]: listen: Invalid argument (in
> lttcomm_listen_unix_sock() at unix.c:173)
> PERROR - 00:25:59.397344426 [1930/1930]: sendmsg: Bad file descriptor
> (in lttcomm_send_unix_sock() at unix.c:292)
> Error: Failed to send data back to client
> PERROR - 00:25:59.397353233 [1930/1930]: close: Bad file descriptor
> (in thread_manage_clients() at main.c:4530)
> Error: Event close: Kernel consumer start failed (channel channel0,
> session my-kernel-session)
> ~ #
> 
> 
> Can you please explain the cause to this error ?

Clearly, lttng is having problem spawning the kernel consumer:

   Error: Spawning consumerd failed

Now for the why, we will need more information from your end.

> 
> 
> I'm running under a 32 bit (x86) vanilla, 4.9.20 kernel with busybox
> with the following lttng versions:

Are you using a distro (yocto/buildroot)?

How can we reproduce the exact environment for this? This will greatly speedup
this, especially if we can spawn such env in qemu.

Also, could you run lttng-sessiond in verbose mode and provide the output
(pastebinit)?

  lttng-sessiond -vvv --verbose-consumer

  ./lttng create my-kernel-session --output=/tmp/my-kernel-trace
  ./lttng enable-event --kernel --syscall open,close

Cheers

-- 
Jonathan Rajotte-Julien
EfficiOS