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| author | Eric Dumazet <edumazet@google.com> | 2021-06-29 17:12:45 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-07-01 21:23:50 +0300 |
| commit | 0dbffbb5335a1e3aa6855e4ee317e25e669dd302 (patch) | |
| tree | 2f7c7aa9e605bfbb4f9bbb6b8e6ce84eb7e5abd0 | |
| parent | 42ca63f980842918560b25f0244307fd83b4777c (diff) | |
| download | linux-0dbffbb5335a1e3aa6855e4ee317e25e669dd302.tar.xz | |
net: annotate data race around sk_ll_usec
sk_ll_usec is read locklessly from sk_can_busy_loop()
while another thread can change its value in sock_setsockopt()
This is correct but needs annotations.
BUG: KCSAN: data-race in __skb_try_recv_datagram / sock_setsockopt
write to 0xffff88814eb5f904 of 4 bytes by task 14011 on cpu 0:
sock_setsockopt+0x1287/0x2090 net/core/sock.c:1175
__sys_setsockopt+0x14f/0x200 net/socket.c:2100
__do_sys_setsockopt net/socket.c:2115 [inline]
__se_sys_setsockopt net/socket.c:2112 [inline]
__x64_sys_setsockopt+0x62/0x70 net/socket.c:2112
do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff88814eb5f904 of 4 bytes by task 14001 on cpu 1:
sk_can_busy_loop include/net/busy_poll.h:41 [inline]
__skb_try_recv_datagram+0x14f/0x320 net/core/datagram.c:273
unix_dgram_recvmsg+0x14c/0x870 net/unix/af_unix.c:2101
unix_seqpacket_recvmsg+0x5a/0x70 net/unix/af_unix.c:2067
____sys_recvmsg+0x15d/0x310 include/linux/uio.h:244
___sys_recvmsg net/socket.c:2598 [inline]
do_recvmmsg+0x35c/0x9f0 net/socket.c:2692
__sys_recvmmsg net/socket.c:2771 [inline]
__do_sys_recvmmsg net/socket.c:2794 [inline]
__se_sys_recvmmsg net/socket.c:2787 [inline]
__x64_sys_recvmmsg+0xcf/0x150 net/socket.c:2787
do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x00000000 -> 0x00000101
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14001 Comm: syz-executor.3 Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/busy_poll.h | 2 | ||||
| -rw-r--r-- | net/core/sock.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index 73af4a64a599..40296ed976a9 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -38,7 +38,7 @@ static inline bool net_busy_loop_on(void) static inline bool sk_can_busy_loop(const struct sock *sk) { - return sk->sk_ll_usec && !signal_pending(current); + return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current); } bool sk_busy_loop_end(void *p, unsigned long start_time); diff --git a/net/core/sock.c b/net/core/sock.c index ba1c0f75cd45..dd9599656c40 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1201,7 +1201,7 @@ set_sndbuf: if (val < 0) ret = -EINVAL; else - sk->sk_ll_usec = val; + WRITE_ONCE(sk->sk_ll_usec, val); } break; case SO_PREFER_BUSY_POLL: |