On Mon, Oct 31, 2022 at 07:17:06PM -0700, Dexuan Cui wrote:
Currently vsock_connectible_has_data() may miss a wakeup operation
between vsock_connectible_has_data() == 0 and the prepare_to_wait().
Fix the race by adding the process to the wait queue before checking
vsock_connectible_has_data().
Fixes: b3f7fd54881b ("af_vsock: separate wait data loop")
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
---
Changes in v2 (Thanks Stefano!):
Fixed a typo in the commit message.
Removed the unnecessary finish_wait() at the end of the loop.
LGTM:
Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
net/vmw_vsock/af_vsock.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index d258fd43092e..884eca7f6743 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1905,8 +1905,11 @@ static int vsock_connectible_wait_data(struct sock *sk,
err = 0;
transport = vsk->transport;
- while ((data = vsock_connectible_has_data(vsk)) == 0) {
+ while (1) {
prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);
+ data = vsock_connectible_has_data(vsk);
+ if (data != 0)
+ break;
if (sk->sk_err != 0 ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
--
2.25.1
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