linux-kernel - [PATCH 15/20] UML - Fix infinite mconsole loop

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Message-ID: <20080117214046.GA6762@c2.user-mode-linux.org>
Date:	Thu, 17 Jan 2008 16:40:46 -0500
From:	Jeff Dike <jdike@...toit.com>
To:	Andrew Morton <akpm@...l.org>
Cc:	Karol Swietlicki <magotari@...il.com>,
	uml-devel <user-mode-linux-devel@...ts.sourceforge.net>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 15/20] UML - Fix infinite mconsole loop

From: Karol Swietlicki <magotari@...il.com>

This patch takes care of a problem with the stopping code.

The function inside the while condition returns 0 to signify a problem.
A problem could be for example a bad command or a bad version of the
mconsole client.
A bad command would terminate the stopping loop and resume the kernel.
This is a problem.

A better solution is to make the loop infinite and don't leave it
until we are explicitly told to.

Signed-off-by: Karol Swietlicki <magotari@...il.com>
Signed-off-by: Jeff Dike <jdike@...ux.intel.com>
---
 arch/um/drivers/mconsole_kern.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux-2.6.22/arch/um/drivers/mconsole_kern.c
===================================================================
--- linux-2.6.22.orig/arch/um/drivers/mconsole_kern.c	2007-12-12 13:44:20.000000000 -0500
+++ linux-2.6.22/arch/um/drivers/mconsole_kern.c	2007-12-12 15:53:08.000000000 -0500
@@ -305,7 +305,9 @@ void mconsole_stop(struct mc_request *re
 	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 	os_set_fd_block(req->originating_fd, 1);
 	mconsole_reply(req, "stopped", 0, 0);
-	while (mconsole_get_request(req->originating_fd, req)) {
+	for (;;) {
+		if (!mconsole_get_request(req->originating_fd, req))
+			continue;
 		if (req->cmd->handler == mconsole_go)
 			break;
 		if (req->cmd->handler == mconsole_stop) {
--
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