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| author |   Eric Dumazet <edumazet@google.com> | 2022-05-13 11:55:41 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2022-05-16 10:31:05 +0100 |
| commit | 4c971d2f3548e4f11b1460ac048f5307e4b39fdb (patch) | |
| tree | ed84c981a11105580c8ecc2c076461da84d21a76 /net/ipv6/datagram.c | |
| parent | Merge branch 'big-tcp' (diff) | |
| download | linux-dev-4c971d2f3548e4f11b1460ac048f5307e4b39fdb.tar.xz linux-dev-4c971d2f3548e4f11b1460ac048f5307e4b39fdb.zip | |
net: annotate races around sk->sk_bound_dev_if
UDP sendmsg() is lockless, and reads sk->sk_bound_dev_if while
this field can be changed by another thread.
Adds minimal annotations to avoid KCSAN splats for UDP.
Following patches will add more annotations to potential lockless readers.
BUG: KCSAN: data-race in __ip6_datagram_connect / udpv6_sendmsg
write to 0xffff888136d47a94 of 4 bytes by task 7681 on cpu 0:
__ip6_datagram_connect+0x6e2/0x930 net/ipv6/datagram.c:221
ip6_datagram_connect+0x2a/0x40 net/ipv6/datagram.c:272
inet_dgram_connect+0x107/0x190 net/ipv4/af_inet.c:576
__sys_connect_file net/socket.c:1900 [inline]
__sys_connect+0x197/0x1b0 net/socket.c:1917
__do_sys_connect net/socket.c:1927 [inline]
__se_sys_connect net/socket.c:1924 [inline]
__x64_sys_connect+0x3d/0x50 net/socket.c:1924
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x50 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff888136d47a94 of 4 bytes by task 7670 on cpu 1:
udpv6_sendmsg+0xc60/0x16e0 net/ipv6/udp.c:1436
inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:652
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg net/socket.c:725 [inline]
____sys_sendmsg+0x39a/0x510 net/socket.c:2413
___sys_sendmsg net/socket.c:2467 [inline]
__sys_sendmmsg+0x267/0x4c0 net/socket.c:2553
__do_sys_sendmmsg net/socket.c:2582 [inline]
__se_sys_sendmmsg net/socket.c:2579 [inline]
__x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x50 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x00000000 -> 0xffffff9b
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7670 Comm: syz-executor.3 Tainted: G W 5.18.0-rc1-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
I chose to not add Fixes: tag because race has minor consequences
and stable teams busy enough.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/datagram.c')
| -rw-r--r-- | net/ipv6/datagram.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c index 39b2327edc4e..df665d4e8f0f 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -218,11 +218,11 @@ ipv4_connected: err = -EINVAL; goto out; } - sk->sk_bound_dev_if = usin->sin6_scope_id; + WRITE_ONCE(sk->sk_bound_dev_if, usin->sin6_scope_id); } if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST)) - sk->sk_bound_dev_if = np->mcast_oif; + WRITE_ONCE(sk->sk_bound_dev_if, np->mcast_oif); /* Connect to link-local address requires an interface */ if (!sk->sk_bound_dev_if) { @@ -798,7 +798,7 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, if (src_idx) { if (fl6->flowi6_oif && src_idx != fl6->flowi6_oif && - (sk->sk_bound_dev_if != fl6->flowi6_oif || + (READ_ONCE(sk->sk_bound_dev_if) != fl6->flowi6_oif || !sk_dev_equal_l3scope(sk, src_idx))) return -EINVAL; fl6->flowi6_oif = src_idx; |