On Wed, Mar 02, 2022 at 09:46:23AM +0100, Antal Koós wrote: > The symptom: > There are two users on a host 'debhost'. > I make 'su' from'user1' to 'user2', and create a file on /dev/shm. > I make 'scp' from another host for 'user2@debhost', but target is the > $HOME and not the /dev/shm. > Result: the file disapperars from /dev/shm.
I am able to reproduce this, with one possibly important note: the removal is not immediate. It happens after a few seconds (less than 10 seconds in my testing). I didn't use a second computer. I just used one. "su" is also not required; I used "sudo -i -u tester" to open the session as the second user account. Here's the first window: unicorn:~$ sudo -i -u tester [sudo] password for greg: tester@unicorn:~$ touch /dev/shm/tester tester@unicorn:~$ inotifywait --monitor /dev/shm/tester Setting up watches. Watches established. /dev/shm/tester ATTRIB /dev/shm/tester DELETE_SELF Here's the second: unicorn:~$ scp foo tester@localhost: tester@localhost's password: foo 100% 21 65.6KB/s 00:00 The final two lines in the first window (ATTRIB and DELETE_SELF) appeared about 8 seconds after the scp command finished. I don't know exactly what's happening here, but my initial guess is that it has something to do with session cleanup. The scp command opens a session as "tester" (or "user2"), does its work, and then terminates the session. Someone who knows systemd, dbus, and all that stuff might be able to suggest next steps.