From: Eric W. Biederman <ebiederm@xmission.com>
Date: Tue, 13 Feb 2007 21:38:58 +0000 (-0700)
Subject: [PATCH] Fix SAK_work workqueue initialization.
X-Git-Tag: v2.6.21-rc1~273^2~7
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7f1f86a0d04e79f8165e6f50d329a520b8cd11e5;p=linux-2.6

[PATCH] Fix SAK_work workqueue initialization.

Somewhere in the rewrite of the work queues my cleanup of SAK handling
got broken.  Maybe I didn't retest it properly or possibly the API
was changing so fast I missed something.  Regardless currently
triggering a SAK now generates an ugly BUG_ON and kills the kernel.

Thanks to Alexey Dobriyan <adobriyan@openvz.org> for spotting this.

This modifies the use of SAK_work to initialize it when the data
structure it resides in is initialized, and to simply call
schedule_work when we need to generate a SAK.  I update both
data structures that have a SAK_work member for consistency.

All of the old PREPARE_WORK calls that are now gone.

If we call schedule_work again before it has processed it
has generated the first SAK it will simply ignore the duplicate
schedule_work request.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/char/keyboard.c b/drivers/char/keyboard.c
index c654a3e0c6..cb8d691576 100644
--- a/drivers/char/keyboard.c
+++ b/drivers/char/keyboard.c
@@ -596,7 +596,6 @@ static void fn_spawn_con(struct vc_data *vc)
 static void fn_SAK(struct vc_data *vc)
 {
 	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
-	PREPARE_WORK(SAK_work, vc_SAK);
 	schedule_work(SAK_work);
 }
 
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 3757610b78..be73c80d69 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -89,7 +89,6 @@ static struct sysrq_key_op sysrq_loglevel_op = {
 static void sysrq_handle_SAK(int key, struct tty_struct *tty)
 {
 	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
-	PREPARE_WORK(SAK_work, vc_SAK);
 	schedule_work(SAK_work);
 }
 static struct sysrq_key_op sysrq_SAK_op = {
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 65672c5747..5289254e7a 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -3442,7 +3442,6 @@ void do_SAK(struct tty_struct *tty)
 {
 	if (!tty)
 		return;
-	PREPARE_WORK(&tty->SAK_work, do_SAK_work);
 	schedule_work(&tty->SAK_work);
 }
 
@@ -3568,7 +3567,7 @@ static void initialize_tty_struct(struct tty_struct *tty)
 	mutex_init(&tty->atomic_write_lock);
 	spin_lock_init(&tty->read_lock);
 	INIT_LIST_HEAD(&tty->tty_files);
-	INIT_WORK(&tty->SAK_work, NULL);
+	INIT_WORK(&tty->SAK_work, do_SAK_work);
 }
 
 /*
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 94ce3e7fc9..c3f8e38393 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -2635,6 +2635,7 @@ static int __init con_init(void)
 	 */
 	for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
 		vc_cons[currcons].d = vc = alloc_bootmem(sizeof(struct vc_data));
+		INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
 		visual_init(vc, currcons, 1);
 		vc->vc_screenbuf = (unsigned short *)alloc_bootmem(vc->vc_screenbuf_size);
 		vc->vc_kmalloced = 0;