Question about the memory mapping of virt-manager

[masatake]

For years, I have gotten random segfaults.
Today, I found the reason with gdb.

The reason is realloc returns NULL with errno = ENOMEM.

The virt-manager process made too many memory mappings:

$ ps -aef | grep virt-ma   
yamato   2515711       1  8 May05 ?        03:02:44 /usr/bin/python3 /usr/bin/virt-manager
yamato   2727748 2727442  0 02:03 pts/16   00:00:00 grep --color=auto virt-ma
$ pmap 2515711 | wc -l  
65534
$ cat /proc/sys/vm/max_map_count 
65530
$ pmap 2515711 | grep ffi | wc -l
64356
$ pmap 2515711 | grep ffi | head 
00007fc46af9e000      4K rw-s- memfd:libffi (deleted)
00007fc46af9f000      4K r-xs- memfd:libffi (deleted)
00007fc46afa0000      4K rw-s- memfd:libffi (deleted)
00007fc46afa1000      4K r-xs- memfd:libffi (deleted)
00007fc46afa2000      4K rw-s- memfd:libffi (deleted)
00007fc46afa3000      4K r-xs- memfd:libffi (deleted)
00007fc46afa4000      4K rw-s- memfd:libffi (deleted)
00007fc46afa5000      4K r-xs- memfd:libffi (deleted)
00007fc46afa6000      4K rw-s- memfd:libffi (deleted)
00007fc46afa7000      4K r-xs- memfd:libffi (deleted)

Do you expect virt-manager maps so many memfds via libffi?

Distro: Fedora 37

I'm still in the stage of understanding my issue. So I have not open an issue on distro's bug tracker.

[masatake]

It seems that libvirt makes too many memory mappings.
I opened https://gitlab.com/libvirt/libvirt/-/merge_requests/275 as the first step for solving my issue.

[masatake]

https://gitlab.gnome.org/GNOME/pygobject/-/merge_requests/214 may fix the leak.