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[82.53.134.234]) by smtp.gmail.com with ESMTPSA id bs33-20020a05620a472100b006fa617ac616sm486080qkb.49.2022.11.02.02.31.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Nov 2022 02:31:43 -0700 (PDT) Date: Wed, 2 Nov 2022 10:31:37 +0100 From: Stefano Garzarella To: Dexuan Cui Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, arseny.krasnov@kaspersky.com, netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kys@microsoft.com, haiyangz@microsoft.com, stephen@networkplumber.org, wei.liu@kernel.org, linux-hyperv@vger.kernel.org Subject: Re: [PATCH v2 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data() Message-ID: <20221102093137.2il5u7opfyddheis@sgarzare-redhat> References: <20221101021706.26152-1-decui@microsoft.com> <20221101021706.26152-3-decui@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20221101021706.26152-3-decui@microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >--- > >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 > > 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 >