From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49J5SobyOTTKmTu+zR8PqL4NlZE3WwJ/3el4olP6T3n92YWp/LETEmSsI5ddtsj5OR7IG/b ARC-Seal: i=1; a=rsa-sha256; t=1524405957; cv=none; d=google.com; s=arc-20160816; b=ZFBp8uf3Lm1VnTTsCIyt0QYPSqYGQnFuBwqRBVRU19x0LfyMFZBPAgc4Ys3o9INubD 8nuWvf7L9Gcv4ctawfn8n+oe6wlUlRtn6bNP8J82p0nGGCJnfBcu3fSQ+8R5lp09EGMv /4fVzAKC6QRsM1aLaZIlHWn1pWPZWzn7zD5vAMxFpFndFhsUsB3DIYRtNGowqWdXJmIf nVWiQuENsGmNT+1WPPrjkzTv2XZBMi3D+N1hhNB/C91eMOGFDF7rJQrQEDTFYZy/OrXt BcOvlgUs6imRJu8foQcdBz/ZsA+WAq6TccCtMBnJoN/KBnQO+0sNEd62uk00c/OsrJru Mzzw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=N0PDp5eskfjo9gejp7TrFetrtESojRy2FcXoIbK4eTU=; b=fCTXn6pRXWl2Z7o06eICh1TfLAJADXIb7PsFhowgY4zuljq4u28csQ9byPFeS9KxkM 9A1PyaL9cBk9xhbgZVJNHIb4fyde3hOaVIA2jlytDpy/eNLiqipCAK566gSlNeRHAdZF YCUi3rBEn990SbPQQEC0L6FfCmLA5iLrP8rlC+nyVCn/9kUZutVxeQyaoI44rSHgBG+5 +6zj7W2YosK8GzrCGIOP6UGdxbNLWDy1ZOyBcD/DtF2zplVB2k154mVU3RDiYUVE35M5 DRHTx2S5Wrb83P6EkEzhtPVr9xvkg5V2CIceir//BxXzhFbY0cuK0l/TgiQdUKjJFqfS rHdw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Andryuk , Eduardo Otubo , Boris Ostrovsky , Juergen Gross Subject: [PATCH 4.14 033/164] xen-netfront: Fix hang on device removal Date: Sun, 22 Apr 2018 15:51:40 +0200 Message-Id: <20180422135136.765606258@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135135.400265110@linuxfoundation.org> References: <20180422135135.400265110@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598455501364355262?= X-GMAIL-MSGID: =?utf-8?q?1598455501364355262?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Andryuk commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61 upstream. A toolstack may delete the vif frontend and backend xenstore entries while xen-netfront is in the removal code path. In that case, the checks for xenbus_read_driver_state would return XenbusStateUnknown, and xennet_remove would hang indefinitely. This hang prevents system shutdown. xennet_remove must be able to handle XenbusStateUnknown, and netback_changed must also wake up the wake_queue for that state as well. Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module") Signed-off-by: Jason Andryuk Cc: Eduardo Otubo Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netfront.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -2008,7 +2008,10 @@ static void netback_changed(struct xenbu case XenbusStateInitialised: case XenbusStateReconfiguring: case XenbusStateReconfigured: + break; + case XenbusStateUnknown: + wake_up_all(&module_unload_q); break; case XenbusStateInitWait: @@ -2139,7 +2142,9 @@ static int xennet_remove(struct xenbus_d xenbus_switch_state(dev, XenbusStateClosing); wait_event(module_unload_q, xenbus_read_driver_state(dev->otherend) == - XenbusStateClosing); + XenbusStateClosing || + xenbus_read_driver_state(dev->otherend) == + XenbusStateUnknown); xenbus_switch_state(dev, XenbusStateClosed); wait_event(module_unload_q,