From beaa4867eec02e6eb78e9e9ef503d7eff612b068 Mon Sep 17 00:00:00 2001
From: Geoff Levand <geoffrey.levand@am.sony.com>
Date: Tue, 9 Dec 2008 13:14:17 -0800
Subject: fbcon: fix workqueue shutdown
Add a call to cancel_work_sync() in fbcon_exit() to cancel any pending
work in the fbcon workqueue.
The current implementation of fbcon_exit() sets the fbcon workqueue
function info->queue.func to NULL, but does not assure that there is no
work pending when it does so. On occasion, depending on system timing,
there will still be pending work in the queue when fbcon_exit() is
called. This results in a null pointer deference when run_workqueue()
tries to call the queue's work function.
Fixes errors on shutdown similar to these:
Console: switching to colour dummy device 80x25
Unable to handle kernel paging request for data at address 0x00000000
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/video/console/fbcon.c | 6 ++++++
1 file changed, 6 insertions(+)
(limited to 'drivers/video/console')
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 67ff370d80af..0b2adefe9e3d 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -3531,12 +3531,18 @@ static void fbcon_exit(void)
softback_buf = 0UL;
for (i = 0; i < FB_MAX; i++) {
+ int pending;
+
mapped = 0;
info = registered_fb[i];
if (info == NULL)
continue;
+ pending = cancel_work_sync(&info->queue);
+ DPRINTK("fbcon: %s pending work\n", (pending ? "canceled" :
+ "no"));
+
for (j = first_fb_vc; j <= last_fb_vc; j++) {
if (con2fb_map[j] == i)
mapped = 1;
--
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