Re: [PATCH] net/vmw_vsock: improve locking in vsock_connect_timeout()

On Fri, 5 Feb 2021 18:19:51 +0100 Stefano Garzarella wrote:

On Fri, Feb 05, 2021 at 03:32:02PM +0100, Norbert Slusarek wrote:

quoted

From: Norbert Slusarek <redacted>
Date: Fri, 5 Feb 2021 13:14:05 +0100
Subject: [PATCH] net/vmw_vsock: improve locking in vsock_connect_timeout()

A possible locking issue in vsock_connect_timeout() was recognized by
Eric Dumazet which might cause a null pointer dereference in
vsock_transport_cancel_pkt(). This patch assures that
vsock_transport_cancel_pkt() will be called within the lock, so a race
condition won't occur which could result in vsk->transport to be set to NULL.

Fixes: 380feae0def7 ("vsock: cancel packets when failing to connect")  

I have a doubt about the tag to use, since until we introduced 
transports in commit c0cfa2d8a788 ("vsock: add multi-transports 
support") this issue didn't cause many problems.

But it must be said that in the commit 380feae0def7 ("vsock: cancel 
packets when failing to connect") the vsock_transport_cancel_pkt() was 
called with the lock held in vsock_stream_connect() and without lock in 
vsock_connect_timeout(), so maybe this tag is okay.

Anyway, the patch LGTM:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Applied, thanks!