Re: [linux-pm] PM: cannot hibernate -- BUG at kernel/workqueue.c:3659

["Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>]

On 01/26/2012 05:21 AM, Rafael J. Wysocki wrote:

> Jiri has already said that the patch works.
> 
> I think we could avoid the issue entirely by introducing thaw_kernel_threads
> and making SNAPSHOT_FREE call it.  No other changes should be necessary.
> 
> IOW, Jiri, does the patch below help?
> 
> [BTW, the freeze_tasks()'s kerneldoc seems to be outdated.  Tejun?]
> 
> ---


Rafael, thanks for the clarification in the other mail.

Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>

I think we need to get this into 3.2-stable as well, as Jiri mentioned.

Regards,
Srivatsa S. Bhat

>  include/linux/freezer.h |    2 ++
>  kernel/power/process.c  |   19 +++++++++++++++++++
>  kernel/power/user.c     |    1 +
>  3 files changed, 22 insertions(+)
> 
> Index: linux/include/linux/freezer.h
> ===================================================================
> --- linux.orig/include/linux/freezer.h
> +++ linux/include/linux/freezer.h
> @@ -39,6 +39,7 @@ extern bool __refrigerator(bool check_kt
>  extern int freeze_processes(void);
>  extern int freeze_kernel_threads(void);
>  extern void thaw_processes(void);
> +extern void thaw_kernel_threads(void);
> 
>  static inline bool try_to_freeze(void)
>  {
> @@ -174,6 +175,7 @@ static inline bool __refrigerator(bool c
>  static inline int freeze_processes(void) { return -ENOSYS; }
>  static inline int freeze_kernel_threads(void) { return -ENOSYS; }
>  static inline void thaw_processes(void) {}
> +static inline void thaw_kernel_threads(void) {}
> 
>  static inline bool try_to_freeze(void) { return false; }
> 
> Index: linux/kernel/power/process.c
> ===================================================================
> --- linux.orig/kernel/power/process.c
> +++ linux/kernel/power/process.c
> @@ -188,3 +188,22 @@ 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");
> +}
> Index: linux/kernel/power/user.c
> ===================================================================
> --- linux.orig/kernel/power/user.c
> +++ linux/kernel/power/user.c
> @@ -274,6 +274,7 @@ static long snapshot_ioctl(struct file *
>  		swsusp_free();
>  		memset(&data->handle, 0, sizeof(struct snapshot_handle));
>  		data->ready = 0;
> +		thaw_kernel_threads();
>  		break;
> 
>  	case SNAPSHOT_PREF_IMAGE_SIZE:
>