diff mbox series

[net] tcp: add annotations around sk->sk_shutdown accesses

Message ID 20230509203656.3864769-1-edumazet@google.com (mailing list archive)
State Accepted
Commit e14cadfd80d76f01bfaa1a8d745b1db19b57d6be
Delegated to: Netdev Maintainers
Headers show
Series [net] tcp: add annotations around sk->sk_shutdown accesses | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 12 this patch: 12
netdev/cc_maintainers warning 1 maintainers not CCed: dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 12 this patch: 12
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 75 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet May 9, 2023, 8:36 p.m. UTC 
Now sk->sk_shutdown is no longer a bitfield, we can add
standard READ_ONCE()/WRITE_ONCE() annotations to silence
KCSAN reports like the following:

BUG: KCSAN: data-race in tcp_disconnect / tcp_poll

write to 0xffff88814588582c of 1 bytes by task 3404 on cpu 1:
tcp_disconnect+0x4d6/0xdb0 net/ipv4/tcp.c:3121
__inet_stream_connect+0x5dd/0x6e0 net/ipv4/af_inet.c:715
inet_stream_connect+0x48/0x70 net/ipv4/af_inet.c:727
__sys_connect_file net/socket.c:2001 [inline]
__sys_connect+0x19b/0x1b0 net/socket.c:2018
__do_sys_connect net/socket.c:2028 [inline]
__se_sys_connect net/socket.c:2025 [inline]
__x64_sys_connect+0x41/0x50 net/socket.c:2025
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88814588582c of 1 bytes by task 3374 on cpu 0:
tcp_poll+0x2e6/0x7d0 net/ipv4/tcp.c:562
sock_poll+0x253/0x270 net/socket.c:1383
vfs_poll include/linux/poll.h:88 [inline]
io_poll_check_events io_uring/poll.c:281 [inline]
io_poll_task_func+0x15a/0x820 io_uring/poll.c:333
handle_tw_list io_uring/io_uring.c:1184 [inline]
tctx_task_work+0x1fe/0x4d0 io_uring/io_uring.c:1246
task_work_run+0x123/0x160 kernel/task_work.c:179
get_signal+0xe64/0xff0 kernel/signal.c:2635
arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306
exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x03 -> 0x00

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/af_inet.c   |  2 +-
 net/ipv4/tcp.c       | 14 ++++++++------
 net/ipv4/tcp_input.c |  4 ++--
 3 files changed, 11 insertions(+), 9 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org May 10, 2023, 9:30 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Tue,  9 May 2023 20:36:56 +0000 you wrote:
> Now sk->sk_shutdown is no longer a bitfield, we can add
> standard READ_ONCE()/WRITE_ONCE() annotations to silence
> KCSAN reports like the following:
> 
> BUG: KCSAN: data-race in tcp_disconnect / tcp_poll
> 
> write to 0xffff88814588582c of 1 bytes by task 3404 on cpu 1:
> tcp_disconnect+0x4d6/0xdb0 net/ipv4/tcp.c:3121
> __inet_stream_connect+0x5dd/0x6e0 net/ipv4/af_inet.c:715
> inet_stream_connect+0x48/0x70 net/ipv4/af_inet.c:727
> __sys_connect_file net/socket.c:2001 [inline]
> __sys_connect+0x19b/0x1b0 net/socket.c:2018
> __do_sys_connect net/socket.c:2028 [inline]
> __se_sys_connect net/socket.c:2025 [inline]
> __x64_sys_connect+0x41/0x50 net/socket.c:2025
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> [...]

Here is the summary with links:
  - [net] tcp: add annotations around sk->sk_shutdown accesses
    https://git.kernel.org/netdev/net/c/e14cadfd80d7

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 940062e08f574fbfeed42f72fa8a4b5ce763110c..c4aab3aacbd89e35520583ab5e17b4e15e53b87e 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -894,7 +894,7 @@  int inet_shutdown(struct socket *sock, int how)
 		   EPOLLHUP, even on eg. unconnected UDP sockets -- RR */
 		fallthrough;
 	default:
-		sk->sk_shutdown |= how;
+		WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | how);
 		if (sk->sk_prot->shutdown)
 			sk->sk_prot->shutdown(sk, how);
 		break;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 20db115c38c492c010733d5a0a3efbb7dbbea13e..4d6392c16b7a5a9a853c27e3a4b258d000738304 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -498,6 +498,7 @@  __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 	__poll_t mask;
 	struct sock *sk = sock->sk;
 	const struct tcp_sock *tp = tcp_sk(sk);
+	u8 shutdown;
 	int state;
 
 	sock_poll_wait(file, sock, wait);
@@ -540,9 +541,10 @@  __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 	 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 	 * blocking on fresh not-connected or disconnected socket. --ANK
 	 */
-	if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
+	shutdown = READ_ONCE(sk->sk_shutdown);
+	if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
 		mask |= EPOLLHUP;
-	if (sk->sk_shutdown & RCV_SHUTDOWN)
+	if (shutdown & RCV_SHUTDOWN)
 		mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
 
 	/* Connected or passive Fast Open socket? */
@@ -559,7 +561,7 @@  __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 		if (tcp_stream_is_readable(sk, target))
 			mask |= EPOLLIN | EPOLLRDNORM;
 
-		if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
+		if (!(shutdown & SEND_SHUTDOWN)) {
 			if (__sk_stream_is_writeable(sk, 1)) {
 				mask |= EPOLLOUT | EPOLLWRNORM;
 			} else {  /* send SIGIO later */
@@ -2867,7 +2869,7 @@  void __tcp_close(struct sock *sk, long timeout)
 	int data_was_unread = 0;
 	int state;
 
-	sk->sk_shutdown = SHUTDOWN_MASK;
+	WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
 
 	if (sk->sk_state == TCP_LISTEN) {
 		tcp_set_state(sk, TCP_CLOSE);
@@ -3119,7 +3121,7 @@  int tcp_disconnect(struct sock *sk, int flags)
 
 	inet_bhash2_reset_saddr(sk);
 
-	sk->sk_shutdown = 0;
+	WRITE_ONCE(sk->sk_shutdown, 0);
 	sock_reset_flag(sk, SOCK_DONE);
 	tp->srtt_us = 0;
 	tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
@@ -4649,7 +4651,7 @@  void tcp_done(struct sock *sk)
 	if (req)
 		reqsk_fastopen_remove(sk, req, false);
 
-	sk->sk_shutdown = SHUTDOWN_MASK;
+	WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
 
 	if (!sock_flag(sk, SOCK_DEAD))
 		sk->sk_state_change(sk);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a057330d6f59d693cdf634dbd22f1243f8171f58..61b6710f337a3a5c24b3f399cc77a404b7e012f9 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4362,7 +4362,7 @@  void tcp_fin(struct sock *sk)
 
 	inet_csk_schedule_ack(sk);
 
-	sk->sk_shutdown |= RCV_SHUTDOWN;
+	WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
 	sock_set_flag(sk, SOCK_DONE);
 
 	switch (sk->sk_state) {
@@ -6599,7 +6599,7 @@  int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 			break;
 
 		tcp_set_state(sk, TCP_FIN_WAIT2);
-		sk->sk_shutdown |= SEND_SHUTDOWN;
+		WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | SEND_SHUTDOWN);
 
 		sk_dst_confirm(sk);