My server monitor happens to sit behind me and normally I have it off but had it on this week. I was a bit surprised to watch my server restart for no reason. Luckily I had a /var/crash log
[127370.214509] [ T715896] ————[ cut here ]———— [127370.214515] [ T715896] Unexpected gfp: 0x40000 (__GFP_COMP). Fixing up to gfp: 0x2d00 (GFP_NOIO|__GFP_ZERO|__GFP_NOWARN). Fix your code! [127370.214520] [ T715896] WARNING: mm/vmalloc.c:3953 at __vmalloc_noprof+0x74/0x90, CPU#3: restic/715896 … [127370.214684] [ T715896] RIP: 0010:__vmalloc_noprof+0x7c/0x90
[169828.633817] [ T950981] usercopy: Kernel memory exposure attempt detected from vmalloc ‘no area’ (offset 0, size 204848)! [169828.635990] [ T950981] ————[ cut here ]———— [169828.635992] [ T950981] kernel BUG at mm/usercopy.c:102! [169828.637185] [ T950981] Oops: invalid opcode: 0000 [#1] SMP NOPTI … [169828.641626] [ T950981] RIP: 0010:usercopy_abort+0x7a/0x7c
Fortunately this one was already know, ZFS 2.4.1 shipped with Ubuntu Server LTS and it…doesn’t support kernel 7. Was really surprised to learn that. Apparently I have to wait until 26.10 in October for a fix :(
For now Im trying to give the docker container more memory, this situation is triggered by the container being killed while writing to ZFS which kills the kernel.