From: "Björn Töpel" <bjorn.topel@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@gmail.com>,
magnus.karlsson@intel.com, magnus.karlsson@gmail.com,
bpf@vger.kernel.org, bjorn.topel@intel.com,
jonathan.lemon@gmail.com,
syzbot+c82697e3043781e08802@syzkaller.appspotmail.com,
hdanton@sina.com, i.maximets@samsung.com
Subject: [PATCH bpf-next v2 0/4] xsk: various CPU barrier and {READ, WRITE}_ONCE fixes
Date: Mon, 26 Aug 2019 08:10:49 +0200 [thread overview]
Message-ID: <20190826061053.15996-1-bjorn.topel@gmail.com> (raw)
This is a four patch series of various barrier, {READ, WRITE}_ONCE
cleanups in the AF_XDP socket code. More details can be found in the
corresponding commit message.
For an AF_XDP socket, most control plane operations are done under the
control mutex (struct xdp_sock, mutex), but there are some places
where members of the struct is read outside the control mutex. This,
as pointed out by Daniel in [1], requires proper {READ,
WRITE}_ONCE-correctness [2] [3]. To address this, and to simplify the
code, the state variable (introduced by Ilya), is now used a point of
synchronization ("is the socket in a valid state, or not").
Thanks,
Björn
[1] https://lore.kernel.org/bpf/beef16bb-a09b-40f1-7dd0-c323b4b89b17@iogearbox.net/
[2] https://lwn.net/Articles/793253/
[3] https://github.com/google/ktsan/wiki/READ_ONCE-and-WRITE_ONCE
v1->v2:
Removed redundant dev check. (Jonathan)
Björn Töpel (4):
xsk: avoid store-tearing when assigning queues
xsk: add proper barriers and {READ, WRITE}_ONCE-correctness for state
xsk: avoid store-tearing when assigning umem
xsk: lock the control mutex in sock_diag interface
net/xdp/xsk.c | 61 +++++++++++++++++++++++++++++++---------------
net/xdp/xsk_diag.c | 3 +++
2 files changed, 45 insertions(+), 19 deletions(-)
--
2.20.1
next reply other threads:[~2019-08-26 6:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 6:10 Björn Töpel [this message]
2019-08-26 6:10 ` [PATCH bpf-next v2 1/4] xsk: avoid store-tearing when assigning queues Björn Töpel
2019-08-26 6:10 ` [PATCH bpf-next v2 2/4] xsk: add proper barriers and {READ, WRITE}_ONCE-correctness for state Björn Töpel
2019-08-26 15:24 ` Ilya Maximets
2019-08-26 16:34 ` Björn Töpel
2019-08-26 17:57 ` Jonathan Lemon
2019-08-26 17:54 ` Jonathan Lemon
2019-09-03 15:22 ` Daniel Borkmann
2019-09-03 15:26 ` Björn Töpel
2019-08-26 6:10 ` [PATCH bpf-next v2 3/4] xsk: avoid store-tearing when assigning umem Björn Töpel
2019-08-26 6:10 ` [PATCH bpf-next v2 4/4] xsk: lock the control mutex in sock_diag interface Björn Töpel
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