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authorRafael J. Wysocki <rjw@sisk.pl>2007-07-19 01:47:36 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 10:04:42 -0700
commit8cdd4936c17bd8085cb0dfacc4a37ccf8d0ada7b (patch)
tree0a9ff7cf1b1a797b1267beeb317507210f4dd170 /kernel/kmod.c
parentb10d911749d37dccfa5873d2088aea3f074b9e45 (diff)
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PM: disable usermode helper before hibernation and suspend
Use a hibernation and suspend notifier to disable the user mode helper before a hibernation/suspend and enable it after the operation. [akpm@linux-foundation.org: build fix] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kmod.c')
-rw-r--r--kernel/kmod.c31
1 files changed, 30 insertions, 1 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 78d365c524ed..928f3678142a 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -33,12 +33,22 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
#include <asm/uaccess.h>
extern int max_threads;
static struct workqueue_struct *khelper_wq;
+/*
+ * If set, both call_usermodehelper_keys() and call_usermodehelper_pipe() exit
+ * immediately returning -EBUSY. Used for preventing user land processes from
+ * being created after the user land has been frozen during a system-wide
+ * hibernation or suspend operation.
+ */
+static int usermodehelper_disabled;
+
#ifdef CONFIG_KMOD
/*
@@ -265,6 +275,24 @@ static void __call_usermodehelper(struct work_struct *work)
}
}
+static int usermodehelper_pm_callback(struct notifier_block *nfb,
+ unsigned long action,
+ void *ignored)
+{
+ switch (action) {
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ usermodehelper_disabled = 1;
+ return NOTIFY_OK;
+ case PM_POST_HIBERNATION:
+ case PM_POST_SUSPEND:
+ usermodehelper_disabled = 0;
+ return NOTIFY_OK;
+ }
+
+ return NOTIFY_DONE;
+}
+
/**
* call_usermodehelper_setup - prepare to call a usermode helper
* @path - path to usermode executable
@@ -374,7 +402,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
goto out;
}
- if (!khelper_wq) {
+ if (!khelper_wq || usermodehelper_disabled) {
retval = -EBUSY;
goto out;
}
@@ -431,4 +459,5 @@ void __init usermodehelper_init(void)
{
khelper_wq = create_singlethread_workqueue("khelper");
BUG_ON(!khelper_wq);
+ pm_notifier(usermodehelper_pm_callback, 0);
}