From a6361f0ca4b25460f2cdf3235ebe8115f622901e Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 23 Apr 2018 17:37:03 -0400 Subject: packet: fix bitfield update race Updates to the bitfields in struct packet_sock are not atomic. Serialize these read-modify-write cycles. Move po->running into a separate variable. Its writes are protected by po->bind_lock (except for one startup case at packet_create). Also replace a textual precondition warning with lockdep annotation. All others are set only in packet_setsockopt. Serialize these updates by holding the socket lock. Analogous to other field updates, also hold the lock when testing whether a ring is active (pg_vec). Fixes: 8dc419447415 ("[PACKET]: Add optional checksum computation for recvmsg") Reported-by: DaeRyong Jeong Reported-by: Byoungyoung Lee Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/packet/internal.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'net/packet/internal.h') diff --git a/net/packet/internal.h b/net/packet/internal.h index a1d2b2319ae9..3bb7c5fb3bff 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -112,10 +112,12 @@ struct packet_sock { int copy_thresh; spinlock_t bind_lock; struct mutex pg_vec_lock; - unsigned int running:1, /* prot_hook is attached*/ - auxdata:1, + unsigned int running; /* bind_lock must be held */ + unsigned int auxdata:1, /* writer must hold sock lock */ origdev:1, - has_vnet_hdr:1; + has_vnet_hdr:1, + tp_loss:1, + tp_tx_has_off:1; int pressure; int ifindex; /* bound device */ __be16 num; @@ -125,8 +127,6 @@ struct packet_sock { enum tpacket_versions tp_version; unsigned int tp_hdrlen; unsigned int tp_reserve; - unsigned int tp_loss:1; - unsigned int tp_tx_has_off:1; unsigned int tp_tstamp; struct net_device __rcu *cached_dev; int (*xmit)(struct sk_buff *skb); -- cgit v1.2.1