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Commit 7f1f86a0 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
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[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: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 552ce544

drivers/char/keyboard.c

+0 −1
Original line number Diff line number Diff line
@@ -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);

}

drivers/char/sysrq.c

+0 −1
Original line number Diff line number Diff line
@@ -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 = {

drivers/char/tty_io.c

+1 −2
Original line number Diff line number Diff line
@@ -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);

}



/*

drivers/char/vt.c

+1 −0
Original line number Diff line number Diff line
@@ -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;