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From: Amit Shah <amit.shah@redhat.com>
To: linuxppc-dev@ozlabs.org
Cc: Rusty Russell <rusty@rustcorp.com.au>,
	linux-kernel@vger.kernel.org, greg@kroah.com,
	Amit Shah <amit.shah@redhat.com>,
	stable@kernel.org
Subject: [PATCH] hvc_console: Don't access hvc_task if not initialised
Date: Thu, 24 Mar 2011 12:59:58 +0530	[thread overview]
Message-ID: <df8ea6d65c1ceeb25b0a3fdfc66995b8a8273ea5.1300951793.git.amit.shah@redhat.com> (raw)

hvc_open() can be called without having any backing device.  This
results in a call to hvc_kick() which calls wake_up_process on a NULL
pointer.  Ensure hvc is initialised by checking for a non-NULL hvc_task
before waking up the hvc thread.

This was found by an autotest run for virtio_console without having a
console backend.

CC: stable@kernel.org
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 drivers/tty/hvc/hvc_console.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index e9cba13..b2cb5cc 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -286,6 +286,9 @@ EXPORT_SYMBOL_GPL(hvc_instantiate);
 /* Wake the sleeping khvcd */
 void hvc_kick(void)
 {
+	if (!hvc_task)
+		return;
+
 	hvc_kicked = 1;
 	wake_up_process(hvc_task);
 }
-- 
1.7.4

             reply	other threads:[~2011-03-24  7:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-24  7:29 Amit Shah [this message]
2011-03-24 14:58 ` hvc_console: Don't access hvc_task if not initialised Milton Miller
2011-03-25  8:47   ` Amit Shah
2011-03-28 17:52     ` Milton Miller
2011-04-20 12:33       ` Amit Shah
2011-04-20 14:34         ` Greg KH
2011-04-20 17:06           ` Amit Shah
2011-04-27  5:01             ` Rusty Russell
2011-04-27  6:31               ` Amit Shah
2011-04-28  0:09                 ` Greg KH
2011-04-28  4:00                   ` Amit Shah

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