[PATCH AUTOSEL 4.19 530/671] xsk: avoid store-tearing when assigning umem
From: Sasha Levin <sashal@kernel.org>
Date: 2020-01-16 18:42:20
Also in:
bpf, lkml, stable
Subsystem:
networking [general], the rest, xdp sockets (af_xdp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
From: Björn Töpel <redacted>
[ Upstream commit 9764f4b301c3e7eb3b75eec85b73cad449cdbb0d ]
The umem member of struct xdp_sock is read outside of the control
mutex, in the mmap implementation, and needs a WRITE_ONCE to avoid
potential store-tearing.
Acked-by: Jonathan Lemon <redacted>
Fixes: 423f38329d26 ("xsk: add umem fill queue support and mmap")
Signed-off-by: Björn Töpel <redacted>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/xdp/xsk.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index b580078f04d1..72caa4fb13f4 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c@@ -454,7 +454,7 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) } xdp_get_umem(umem_xs->umem); - xs->umem = umem_xs->umem; + WRITE_ONCE(xs->umem, umem_xs->umem); sockfd_put(sock); } else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) { err = -EINVAL;
@@ -534,7 +534,7 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, /* Make sure umem is ready before it can be seen by others */ smp_wmb(); - xs->umem = umem; + WRITE_ONCE(xs->umem, umem); mutex_unlock(&xs->mutex); return 0; }
--
2.20.1