watchdog: open /dev/watchdog0 only if it exists

[yuwata]

Fixes #24661.

[bluca]

@mrc0mmand vagrant looks sad today:

23:06:24 cp: cannot stat '/root/systemd/vagrant-*': No such file or directory
23:06:24 cp: cannot stat '/tmp/vagrant-*-console.log': No such file or directory
23:06:24 2022-09-13 22:06:24,474 [agent-control/fetch_artifacts] INFO: Fetching artifacts from node n27-5-5.pool.ci.centos.org: (remote: ~/vagrant-logs*, local: ./artifacts_wqqfuldt)
23:06:24 2022-09-13 22:06:24,474 [agent-control/execute_local_command] INFO: Executing a LOCAL command: /usr/bin/scp -r -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no root@n27-5-5.pool.ci.centos.org:~/vagrant-logs* ./artifacts_wqqfuldt
23:06:24 2022-09-13 22:06:24,643 [agent-control/main] ERROR: Execution failed
23:06:24 Traceback (most recent call last):
23:06:24   File "./agent-control.py", line 403, in main
23:06:24     ac.execute_remote_command(command, artifacts_dir="~/vagrant-logs*")
23:06:24   File "./agent-control.py", line 164, in execute_remote_command
23:06:24     raise RuntimeError("Remote command exited with an unexpected return code "
23:06:24 RuntimeError: Remote command exited with an unexpected return code (got: 1, expected: 0), bailing out

[mrc0mmand]

@mrc0mmand vagrant looks sad today:

23:06:24 cp: cannot stat '/root/systemd/vagrant-*': No such file or directory
23:06:24 cp: cannot stat '/tmp/vagrant-*-console.log': No such file or directory
23:06:24 2022-09-13 22:06:24,474 [agent-control/fetch_artifacts] INFO: Fetching artifacts from node n27-5-5.pool.ci.centos.org: (remote: ~/vagrant-logs*, local: ./artifacts_wqqfuldt)
23:06:24 2022-09-13 22:06:24,474 [agent-control/execute_local_command] INFO: Executing a LOCAL command: /usr/bin/scp -r -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no root@n27-5-5.pool.ci.centos.org:~/vagrant-logs* ./artifacts_wqqfuldt
23:06:24 2022-09-13 22:06:24,643 [agent-control/main] ERROR: Execution failed
23:06:24 Traceback (most recent call last):
23:06:24   File "./agent-control.py", line 403, in main
23:06:24     ac.execute_remote_command(command, artifacts_dir="~/vagrant-logs*")
23:06:24   File "./agent-control.py", line 164, in execute_remote_command
23:06:24     raise RuntimeError("Remote command exited with an unexpected return code "
23:06:24 RuntimeError: Remote command exited with an unexpected return code (got: 1, expected: 0), bailing out

Whoops, I forgot to reschedule this one. I have this issue on my TODO list with a possible solution, hopefully will have a fix ready soon, thanks for the ping.

[bluca]

/dev/watchdog0 should exist on all supported kernel versions, let's wait for the reporter to provide more information

[yuwata]

Applied the suggestion. PTAL.