From: "Björn Töpel" <bjorn.topel@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@intel.com>,
magnus.karlsson@intel.com, magnus.karlsson@gmail.com,
bpf@vger.kernel.org, jonathan.lemon@gmail.com,
syzbot+c82697e3043781e08802@syzkaller.appspotmail.com,
hdanton@sina.com, i.maximets@samsung.com
Subject: [PATCH bpf-next v3 2/4] xsk: avoid store-tearing when assigning umem
Date: Wed, 4 Sep 2019 13:49:11 +0200 [thread overview]
Message-ID: <20190904114913.17217-3-bjorn.topel@gmail.com> (raw)
In-Reply-To: <20190904114913.17217-1-bjorn.topel@gmail.com>
From: Björn Töpel <bjorn.topel@intel.com>
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 <jonathan.lemon@gmail.com>
Fixes: 423f38329d26 ("xsk: add umem fill queue support and mmap")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
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 271d8d3fb11e..8c9056f06989 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -644,7 +644,7 @@ 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;
@@ -751,7 +751,7 @@ 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
next prev parent reply other threads:[~2019-09-04 11:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 11:49 [PATCH bpf-next v3 0/4] xsk: various CPU barrier and {READ, WRITE}_ONCE Björn Töpel
2019-09-04 11:49 ` [PATCH bpf-next v3 1/4] xsk: avoid store-tearing when assigning queues Björn Töpel
2019-09-04 11:49 ` Björn Töpel [this message]
2019-09-04 11:49 ` [PATCH bpf-next v3 3/4] xsk: use state member for socket synchronization Björn Töpel
2019-09-04 16:40 ` Jonathan Lemon
2019-09-04 11:49 ` [PATCH bpf-next v3 4/4] xsk: lock the control mutex in sock_diag interface Björn Töpel
2019-09-05 13:14 ` [PATCH bpf-next v3 0/4] xsk: various CPU barrier and {READ, WRITE}_ONCE Daniel Borkmann
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