From dfe1064adf369e913cf709437676ab20768de804 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 27 Sep 2021 17:29:24 -0700 Subject: [PATCH] net: udp: annotate data race around udp_sk(sk)->corkflag commit a9f5970767d11eadc805d5283f202612c7ba1f59 upstream. up->corkflag field can be read or written without any lock. Annotate accesses to avoid possible syzbot/KCSAN reports. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/udp.c | 10 +++++----- net/ipv6/udp.c | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index cf5c4d2f68c1..4faeb698c33c 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -882,7 +882,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) __be16 dport; u8 tos; int err, is_udplite = IS_UDPLITE(sk); - int corkreq = up->corkflag || msg->msg_flags&MSG_MORE; + int corkreq = READ_ONCE(up->corkflag) || msg->msg_flags&MSG_MORE; int (*getfrag)(void *, char *, int, int, int, struct sk_buff *); struct sk_buff *skb; struct ip_options_data opt_copy; @@ -1165,7 +1165,7 @@ int udp_sendpage(struct sock *sk, struct page *page, int offset, } up->len += size; - if (!(up->corkflag || (flags&MSG_MORE))) + if (!(READ_ONCE(up->corkflag) || (flags&MSG_MORE))) ret = udp_push_pending_frames(sk); if (!ret) ret = size; @@ -2373,9 +2373,9 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, switch (optname) { case UDP_CORK: if (val != 0) { - up->corkflag = 1; + WRITE_ONCE(up->corkflag, 1); } else { - up->corkflag = 0; + WRITE_ONCE(up->corkflag, 0); lock_sock(sk); push_pending_frames(sk); release_sock(sk); @@ -2482,7 +2482,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, switch (optname) { case UDP_CORK: - val = up->corkflag; + val = READ_ONCE(up->corkflag); break; case UDP_ENCAP: diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index d9d25b9c07ae..3411b36b8a50 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1135,7 +1135,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) struct ipcm6_cookie ipc6; int addr_len = msg->msg_namelen; int ulen = len; - int corkreq = up->corkflag || msg->msg_flags&MSG_MORE; + int corkreq = READ_ONCE(up->corkflag) || msg->msg_flags&MSG_MORE; int err; int connected = 0; int is_udplite = IS_UDPLITE(sk); -- 2.20.1