Linux 7.1 merges support for user.* extended attributes (xattrs) on sockets, a feature requested by GNOME and systemd developers. Previously, sockets in sockfs had no xattr support at all. The change allows services to label their sockets with metadata such as the IPC protocol they speak (e.g., user.varlink=1), enabling eBPF-based traffic capture and socket discovery for debugging. systemd-journald also plans to use socket xattrs for protocol negotiation on /dev/log. Sockfs sockets get per-inode limits of 128 xattrs and 128KB total value size. The feature is especially useful in container environments where high-privilege socket identification methods are unavailable. Linus Torvalds merged the change without objections.
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