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Subject: Re: [PATCH] xprtrdma: Ensure connect worker is awoken after connect
 error
From:   Chuck Lever <chuck.lever@oracle.com>
In-Reply-To: <20200621145934.4069.31886.stgit@manet.1015granger.net>
Date:   Thu, 25 Jun 2020 15:19:39 -0400
Cc:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        linux-rdma <linux-rdma@vger.kernel.org>
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References: <20200621145934.4069.31886.stgit@manet.1015granger.net>
To:     Dan Aloni <dan@kernelim.com>,
        Anna Schumaker <anna.schumaker@netapp.com>
Sender: linux-nfs-owner@vger.kernel.org
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Anna, please drop this one. It appears to trigger a particularly nasty
use-after-free. I'll follow up with a more complete fix soon.

(Yes, a wake-up on connect errors is indeed necessary... but the connect
worker needs to be re-organized to deal properly with it).


> On Jun 21, 2020, at 10:59 AM, Chuck Lever <chuck.lever@oracle.com> =
wrote:
>=20
> From: Dan Aloni <dan@kernelim.com>
>=20
> The connect worker sleeps waiting for either successful connection
> establishment or an error. Commit e28ce90083f0 ("xprtrdma: kmalloc
> rpcrdma_ep separate from rpcrdma_xprt") mistakenly removed the
> wake-up in cases when connection establishment fails.
>=20
> Fixes: e28ce90083f0 ("xprtrdma: kmalloc rpcrdma_ep separate from =
rpcrdma_xprt")
> Signed-off-by: Dan Aloni <dan@kernelim.com>
> [ cel: rebased on recent fixes to 5.8-rc; patch description rewritten =
]
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> net/sunrpc/xprtrdma/verbs.c |    1 +
> 1 file changed, 1 insertion(+)
>=20
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 2198c8ec8dff..54c6809bf06e 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -296,6 +296,7 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, =
struct rdma_cm_event *event)
> 		ep->re_connect_status =3D -ECONNABORTED;
> disconnected:
> 		rpcrdma_force_disconnect(ep);
> +		wake_up_all(&ep->re_connect_wait);
> 		return rpcrdma_ep_put(ep);
> 	default:
> 		break;
>=20

--
Chuck Lever