From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+vxl49IVNucEyPkX+tDC6bz6QQR7c3GzSfb/jTtSmLvTPh2fq0NVBab7sKU3UwDr+fb26j ARC-Seal: i=1; a=rsa-sha256; t=1524406615; cv=none; d=google.com; s=arc-20160816; b=q2ZYcERFe+pN/CsFX+8lnLDEzv8TH6UIxJMCl2pfkHEYh8jKr+owhLB5G8L1WTOwk9 GgaphVo/snnSdCoC8ffqZn4ZogtyH9xl0PpqxEWazhBh6ZhjSN4j126xjvXYJTuJaGIK ckhYnUR4XHSYohU947QY5LVOaICL5W6jWVBjYvXUP9MC2IpK6uh0eA9X+dPEbjIhGigN 72PiEw6g6aBh1UAbrGvpTgBiD50/SU+44V0FO0U0G0RrbtNFha4bNRKq6PnVKdmwtCC7 r4XACwps+GSW2trIT1SVu74XoRSOLdTzkA4FvL+oOZRFtL4+QM2g2VfdMJCGnXXlrZrP J9vg== 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=TF2MttnB/sLlOKnmHuzVe7MDrMhqTkSOHU0Ypc33GI0=; b=J0GuJ78CN4yst1rkNrG3K9GU2x5f64nYOlV6v8ARfGKmsvowx7JBWk0Tr7jry9OOOa jWZ6kY33Afk8aqnBY0LQJGDFH/WoPLBC0QSG/S8iHWLIwK4JJaqDih+hp6u2p3yfeLqg r/KcsWSJ00blfl0T2GFcNtnAU8dW9MA54poS8auuIi6wcpBJken9cpS1GG9OjUaP7IHB 81uYh4uY1BriT0/ez5kzs2u7ZfQViylGYpKnrKbL7/WMl/Bd5HuR8vE79EO/5zXEjxp/ lB/oTRRbcrI3KVD0S182rdqFMrohVbf7IMGvoYD0YSyxDyDuB/aGBOQF0bd4vjq8RVH0 Ifkg== 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 4.4 33/97] xen-netfront: Fix hang on device removal Date: Sun, 22 Apr 2018 15:53:11 +0200 Message-Id: <20180422135307.198967865@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135304.577223025@linuxfoundation.org> References: <20180422135304.577223025@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?1598456191329135276?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-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 @@ -2024,7 +2024,10 @@ static void netback_changed(struct xenbu case XenbusStateInitialised: case XenbusStateReconfiguring: case XenbusStateReconfigured: + break; + case XenbusStateUnknown: + wake_up_all(&module_unload_q); break; case XenbusStateInitWait: @@ -2155,7 +2158,9 @@ 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,