Recently my Undertow application is triggering Cloud Run to report the following:

Container Sandbox Limitation: Unsupported syscall setsockopt(0x13,0x1,0xa,0x3e05747fe5a0,0x4,0xfc1abc10). Please, refer to https://gvisor.dev/c/linux/amd64/setsockopt for more information.

I've done an strace and it seems that the socket option Out-of-band Inlining (SO_OOBINLINE) is being sent. I don't think it matters if the setting of this option is enabled or disabled.

I don't understand sockets any better than this but I feel like a XIO developer would understand the issue.