[PATCH -mm] swsusp: fix possible lockup in user interface

[Rafael J. Wysocki]

Hi,

The appended patch fixes possible system lockup that may result from
calling pm_prepare_console() after processes has been frozen.

Please apply.

Greetings,
Rafael


Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>

 kernel/power/user.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

Index: linux-2.6.16-rc1-mm2/kernel/power/user.c
===================================================================
--- linux-2.6.16-rc1-mm2.orig/kernel/power/user.c	2006-01-21 23:42:32.000000000 +0100
+++ linux-2.6.16-rc1-mm2/kernel/power/user.c	2006-01-22 17:49:07.000000000 +0100
@@ -141,9 +141,14 @@ static int snapshot_ioctl(struct inode *
 			break;
 		sys_sync();
 		down(&pm_sem);
+		pm_prepare_console();
 		disable_nonboot_cpus();
-		if (freeze_processes())
+		if (freeze_processes()) {
+			thaw_processes();
+			enable_nonboot_cpus();
+			pm_restore_console();
 			error = -EBUSY;
+		}
 		up(&pm_sem);
 		if (!error)
 			data->frozen = 1;
@@ -155,6 +160,7 @@ static int snapshot_ioctl(struct inode *
 		down(&pm_sem);
 		thaw_processes();
 		enable_nonboot_cpus();
+		pm_restore_console();
 		up(&pm_sem);
 		data->frozen = 0;
 		break;
@@ -165,7 +171,6 @@ static int snapshot_ioctl(struct inode *
 			break;
 		}
 		down(&pm_sem);
-		pm_prepare_console();
 		/* Free memory before shutting down devices. */
 		error = swsusp_shrink_memory();
 		if (!error) {
@@ -176,7 +181,6 @@ static int snapshot_ioctl(struct inode *
 				device_resume();
 			}
 		}
-		pm_restore_console();
 		up(&pm_sem);
 		if (!error)
 			error = put_user(in_suspend, (unsigned int __user *)arg);
-
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