From: John Fastabend <john.fastabend@gmail.com>
To: Christian Brauner <brauner@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jan Kara <jack@suse.cz>, Simon Horman <horms@kernel.org>,
Kuniyuki Iwashima <kuniyu@google.com>,
Willem de Bruijn <willemb@google.com>,
linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH 1/2] fs: Add bpf_sock_read_xattr() kfunc to read socket xattrs
Date: Thu, 18 Jun 2026 11:20:34 -0700 [thread overview]
Message-ID: <ajQ0p4ernwLzxkhu@john-p8> (raw)
In-Reply-To: <20260617-work-bpf-sock-xattr-v1-1-a1276f7c9da3@kernel.org>
On Wed, Jun 17, 2026 at 01:18:27PM +0200, Christian Brauner wrote:
>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.
[...]
>
>Link: https://github.com/systemd/systemd/pull/40559 [1]
>Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
>---
Nice this will simplify some of our socket tracking.
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
next prev parent reply other threads:[~2026-06-18 18:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-17 11:18 [PATCH 0/2] Add bpf_sock_read_xattr() kfunc to read socket xattrs Christian Brauner
2026-06-17 11:18 ` [PATCH 1/2] fs: " Christian Brauner
2026-06-18 18:20 ` John Fastabend [this message]
2026-06-17 11:18 ` [PATCH 2/2] selftests/bpf: Add test for bpf_sock_read_xattr() kfunc Christian Brauner
2026-06-18 18:24 ` John Fastabend
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