On Wed, 17 Jun 2026 13:18:26 +0200, Christian Brauner wrote:

Add bpf_sock_read_xattr() kfunc to read socket xattrs

In c8db08110cbe ("Merge tag 'vfs-7.1-rc1.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs")
we added support for extended attributes for sockets. This comes in two
flavors: sockfs and non-sockfs/filesystem sockets. Filesystem sockets
are actual filesystem objects so reading xattrs must use dedicated fs
helpers such as bpf_get_dentry_xattr() and bpf_get_file_xattr(). Those
are inherently sleeping operations. Sockfs sockets on the other hand
don't need to use sleeping operations as the underlying data structure
is lockless. In addition, retrieval of sockfs extended attributes often
happens from LSM hooks that only provide struct socket and it's
completely nonsensical to grab a reference to a file, then force a
sleeping operation to retrieve the xattr and drop the reference. We know
that the sockfs file cannot go away while the LSM hook runs.

[...]

Applied to the vfs-7.3.kfunc branch of the vfs/vfs.git tree.
Patches in the vfs-7.3.kfunc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-7.3.kfunc

[1/2] fs: Add bpf_sock_read_xattr() kfunc to read socket xattrs
      https://git.kernel.org/vfs/vfs/c/f80386e3838e
[2/2] selftests/bpf: Add test for bpf_sock_read_xattr() kfunc
      https://git.kernel.org/vfs/vfs/c/99a63a6aff40