4 files changed, 61 insertions, 7 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index 0c4defe6d3b8..21724eee5206 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -231,8 +231,28 @@ extern int pm_test_level;
 #ifdef CONFIG_SUSPEND_FREEZER
 static inline int suspend_freeze_processes(void)
 {
-        int error = freeze_processes();
-        return error ? : freeze_kernel_threads();
+        int error;
+
+        error = freeze_processes();
+
+        /*
+         * freeze_processes() automatically thaws every task if freezing
+         * fails. So we need not do anything extra upon error.
+         */
+        if (error)
+                goto Finish;
+
+        error = freeze_kernel_threads();
+
+        /*
+         * freeze_kernel_threads() thaws only kernel threads upon freezing
+         * failure. So we have to thaw the userspace tasks ourselves.
+         */
+        if (error)
+                thaw_processes();
+
+ Finish:
+        return error;
 }
 
 static inline void suspend_thaw_processes(void)
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 77274c9ba2f1..7e426459e60a 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -143,7 +143,10 @@ int freeze_processes(void)
 /**
  * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
  *
- * On success, returns 0.  On failure, -errno and system is fully thawed.
+ * On success, returns 0.  On failure, -errno and only the kernel threads are
+ * thawed, so as to give a chance to the caller to do additional cleanups
+ * (if any) before thawing the userspace tasks. So, it is the responsibility
+ * of the caller to thaw the userspace tasks, when the time is right.
  */
 int freeze_kernel_threads(void)
 {
@@ -159,7 +162,7 @@ int freeze_kernel_threads(void)
         BUG_ON(in_atomic());
 
         if (error)
-                thaw_processes();
+                thaw_kernel_threads();
         return error;
 }
 
@@ -188,3 +191,22 @@ void thaw_processes(void)
         printk("done.\n");
 }
 
+void thaw_kernel_threads(void)
+{
+        struct task_struct *g, *p;
+
+        pm_nosig_freezing = false;
+        printk("Restarting kernel threads ... ");
+
+        thaw_workqueues();
+
+        read_lock(&tasklist_lock);
+        do_each_thread(g, p) {
+                if (p->flags & (PF_KTHREAD | PF_WQ_WORKER))
+                        __thaw_task(p);
+        } while_each_thread(g, p);
+        read_unlock(&tasklist_lock);
+
+        schedule();
+        printk("done.\n");
+}
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 1cf88900ec4f..6a768e537001 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -812,7 +812,8 @@ unsigned int snapshot_additional_pages(struct zone *zone)
         unsigned int res;
 
         res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
-        res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE);
+        res += DIV_ROUND_UP(res * sizeof(struct bm_block),
+                            LINKED_PAGE_DATA_SIZE);
         return 2 * res;
 }
 
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 6b1ab7a88522..3e100075b13c 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -249,13 +249,15 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                 }
                 pm_restore_gfp_mask();
                 error = hibernation_snapshot(data->platform_support);
-                if (!error) {
+                if (error) {
+                        thaw_kernel_threads();
+                } else {
                         error = put_user(in_suspend, (int __user *)arg);
                         if (!error && !freezer_test_done)
                                 data->ready = 1;
                         if (freezer_test_done) {
                                 freezer_test_done = false;
-                                thaw_processes();
+                                thaw_kernel_threads();
                         }
                 }
                 break;
@@ -274,6 +276,15 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                 swsusp_free();
                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
                 data->ready = 0;
+                /*
+                 * It is necessary to thaw kernel threads here, because
+                 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
+                 * SNAPSHOT_FREE.  In that case, if kernel threads were not
+                 * thawed, the preallocation of memory carried out by
+                 * hibernation_snapshot() might run into problems (i.e. it
+                 * might fail or even deadlock).
+                 */
+                thaw_kernel_threads();
                 break;
 
         case SNAPSHOT_PREF_IMAGE_SIZE: