Creation of /tmp/.trace2seccomp.* leading to OOM when mdns jail=0

[edrikk]

The updated procd has resulted in an issue where setting jail to 0:

root@AP1B:/etc/config# cat umdns
config umdns
        option jail 0
        list network lan

Results in the creation of an ever growing /tmp/.trace2seccomp.* file. In case of 256MB RAM APs setup like this I had 3 devices OOM after 26 hours.
This is with the latest head in openwrt master (as at Sept. 27th), and the change in behavior began with the procd update of last week.

The files are currently sitting at 11MB after 1 hour uptime following the OOM reboot.
The generation of this file is new behavior so reporting it (of course the resulting OOM is important).

root@AP1B:/tmp# ls -ltra ./.trace*
-rw-r--r--    1 root     root      11024235 Sep 27 14:09 ./.trace2seccomp.1790524807.ndjson

The contents of the file:

{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":66,"syscall":"writev","args":[2,549394855008,1,548282463760,548282473588,1],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":211,"syscall":"sendmsg","args":[8,549394854024,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":66,"syscall":"writev","args":[2,549394855008,1,548282463760,548282473588,1],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":211,"syscall":"sendmsg","args":[8,549394854024,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,55,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":198,"syscall":"socket","args":[1,1,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,1,0,0,1,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,2,1,1,2,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":203,"syscall":"connect","args":[11,549394855048,110,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":57,"syscall":"close","args":[11,0,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,1000,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":212,"syscall":"recvmsg","args":[8,549394854760,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,961,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":212,"syscall":"recvmsg","args":[8,549394854760,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,934,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":198,"syscall":"socket","args":[1,1,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,1,0,0,1,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,2,1,1,2,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":203,"syscall":"connect","args":[11,549394855048,110,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":57,"syscall":"close","args":[11,0,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,1000,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":198,"syscall":"socket","args":[1,1,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,1,0,0,1,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,2,1,1,2,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":203,"syscall":"connect","args":[11,549394855048,110,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":57,"syscall":"close","args":[11,0,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,1000,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":198,"syscall":"socket","args":[1,1,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,1,0,0,1,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,2,1,1,2,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":203,"syscall":"connect","args":[11,549394855048,110,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":57,"syscall":"close","args":[11,0,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,1000,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":212,"syscall":"recvmsg","args":[8,549394854760,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,288,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":212,"syscall":"recvmsg","args":[8,549394854760,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,288,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":198,"syscall":"socket","args":[1,1,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,1,0,0,1,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,2,1,1,2,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":203,"syscall":"connect","args":[11,549394855048,110,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":57,"syscall":"close","args":[11,0,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,1000,0,8],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":198,"syscall":"socket","args":[1,1,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,1,0,0,1,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":25,"syscall":"fcntl","args":[11,2,1,1,2,11],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":203,"syscall":"connect","args":[11,549394855048,110,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":57,"syscall":"close","args":[11,0,0,0,0,0],"action":"allow"}
{"event":"syscall","pid":2993,"comm":"umdns","phase":"app","nr":22,"syscall":"epoll_pwait","args":[3,548282118976,10,1000,0,8],"action":"allow"}