| Message ID | 20130307175359.GB15631@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Thu, Mar 7, 2013 at 9:53 AM, Oleg Nesterov <oleg@redhat.com> wrote: > hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. > > We can simply kill this mutex, hotkey_poll_stop_sync() does not need > to serialize with hotkey_kthread(). When kthread_stop() returns the > thread is already dead, it called do_exit()->complete_vfork_done(). > > Reported-by: Artem Savkov <artem.savkov@gmail.com> > Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > Reviewed-by: Mandeep Singh Baines <msb@chromium.org> > --- x/drivers/platform/x86/thinkpad_acpi.c > +++ x/drivers/platform/x86/thinkpad_acpi.c > @@ -1965,9 +1965,6 @@ struct tp_nvram_state { > /* kthread for the hotkey poller */ > static struct task_struct *tpacpi_hotkey_task; > > -/* Acquired while the poller kthread is running, use to sync start/stop */ > -static struct mutex hotkey_thread_mutex; > - > /* > * Acquire mutex to write poller control variables as an > * atomic block. > @@ -2463,8 +2460,6 @@ static int hotkey_kthread(void *data) > unsigned int poll_freq; > bool was_frozen; > > - mutex_lock(&hotkey_thread_mutex); > - > if (tpacpi_lifecycle == TPACPI_LIFE_EXITING) > goto exit; > > @@ -2524,7 +2519,6 @@ static int hotkey_kthread(void *data) > } > > exit: > - mutex_unlock(&hotkey_thread_mutex); > return 0; > } > > @@ -2534,9 +2528,6 @@ static void hotkey_poll_stop_sync(void) > if (tpacpi_hotkey_task) { > kthread_stop(tpacpi_hotkey_task); > tpacpi_hotkey_task = NULL; > - mutex_lock(&hotkey_thread_mutex); > - /* at this point, the thread did exit */ > - mutex_unlock(&hotkey_thread_mutex); > } > } > > @@ -3235,7 +3226,6 @@ static int __init hotkey_init(struct ibm > mutex_init(&hotkey_mutex); > > #ifdef CONFIG_THINKPAD_ACPI_HOTKEY_POLL > - mutex_init(&hotkey_thread_mutex); > mutex_init(&hotkey_thread_data_mutex); > #endif > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 07 Mar 2013, Mandeep Singh Baines wrote: > On Thu, Mar 7, 2013 at 9:53 AM, Oleg Nesterov <oleg@redhat.com> wrote: > > hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. > > > > We can simply kill this mutex, hotkey_poll_stop_sync() does not need > > to serialize with hotkey_kthread(). When kthread_stop() returns the > > thread is already dead, it called do_exit()->complete_vfork_done(). > > > > Reported-by: Artem Savkov <artem.savkov@gmail.com> > > Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > > > Reviewed-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
On 03/26, Rafael J. Wysocki wrote: > > On Thursday, March 07, 2013 06:53:59 PM Oleg Nesterov wrote: > > hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. > > > > We can simply kill this mutex, hotkey_poll_stop_sync() does not need > > to serialize with hotkey_kthread(). When kthread_stop() returns the > > thread is already dead, it called do_exit()->complete_vfork_done(). > > > > Reported-by: Artem Savkov <artem.savkov@gmail.com> > > Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > I wonder if anyone is taking care of this patch? IIRC, it is already in -mm tree. > Rafael > > > > --- x/drivers/platform/x86/thinkpad_acpi.c > > +++ x/drivers/platform/x86/thinkpad_acpi.c > > @@ -1965,9 +1965,6 @@ struct tp_nvram_state { > > /* kthread for the hotkey poller */ > > static struct task_struct *tpacpi_hotkey_task; > > > > -/* Acquired while the poller kthread is running, use to sync start/stop */ > > -static struct mutex hotkey_thread_mutex; > > - > > /* > > * Acquire mutex to write poller control variables as an > > * atomic block. > > @@ -2463,8 +2460,6 @@ static int hotkey_kthread(void *data) > > unsigned int poll_freq; > > bool was_frozen; > > > > - mutex_lock(&hotkey_thread_mutex); > > - > > if (tpacpi_lifecycle == TPACPI_LIFE_EXITING) > > goto exit; > > > > @@ -2524,7 +2519,6 @@ static int hotkey_kthread(void *data) > > } > > > > exit: > > - mutex_unlock(&hotkey_thread_mutex); > > return 0; > > } > > > > @@ -2534,9 +2528,6 @@ static void hotkey_poll_stop_sync(void) > > if (tpacpi_hotkey_task) { > > kthread_stop(tpacpi_hotkey_task); > > tpacpi_hotkey_task = NULL; > > - mutex_lock(&hotkey_thread_mutex); > > - /* at this point, the thread did exit */ > > - mutex_unlock(&hotkey_thread_mutex); > > } > > } > > > > @@ -3235,7 +3226,6 @@ static int __init hotkey_init(struct ibm > > mutex_init(&hotkey_mutex); > > > > #ifdef CONFIG_THINKPAD_ACPI_HOTKEY_POLL > > - mutex_init(&hotkey_thread_mutex); > > mutex_init(&hotkey_thread_data_mutex); > > #endif > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thursday, March 07, 2013 06:53:59 PM Oleg Nesterov wrote: > hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. > > We can simply kill this mutex, hotkey_poll_stop_sync() does not need > to serialize with hotkey_kthread(). When kthread_stop() returns the > thread is already dead, it called do_exit()->complete_vfork_done(). > > Reported-by: Artem Savkov <artem.savkov@gmail.com> > Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> > Signed-off-by: Oleg Nesterov <oleg@redhat.com> I wonder if anyone is taking care of this patch? Rafael > --- x/drivers/platform/x86/thinkpad_acpi.c > +++ x/drivers/platform/x86/thinkpad_acpi.c > @@ -1965,9 +1965,6 @@ struct tp_nvram_state { > /* kthread for the hotkey poller */ > static struct task_struct *tpacpi_hotkey_task; > > -/* Acquired while the poller kthread is running, use to sync start/stop */ > -static struct mutex hotkey_thread_mutex; > - > /* > * Acquire mutex to write poller control variables as an > * atomic block. > @@ -2463,8 +2460,6 @@ static int hotkey_kthread(void *data) > unsigned int poll_freq; > bool was_frozen; > > - mutex_lock(&hotkey_thread_mutex); > - > if (tpacpi_lifecycle == TPACPI_LIFE_EXITING) > goto exit; > > @@ -2524,7 +2519,6 @@ static int hotkey_kthread(void *data) > } > > exit: > - mutex_unlock(&hotkey_thread_mutex); > return 0; > } > > @@ -2534,9 +2528,6 @@ static void hotkey_poll_stop_sync(void) > if (tpacpi_hotkey_task) { > kthread_stop(tpacpi_hotkey_task); > tpacpi_hotkey_task = NULL; > - mutex_lock(&hotkey_thread_mutex); > - /* at this point, the thread did exit */ > - mutex_unlock(&hotkey_thread_mutex); > } > } > > @@ -3235,7 +3226,6 @@ static int __init hotkey_init(struct ibm > mutex_init(&hotkey_mutex); > > #ifdef CONFIG_THINKPAD_ACPI_HOTKEY_POLL > - mutex_init(&hotkey_thread_mutex); > mutex_init(&hotkey_thread_data_mutex); > #endif > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday, March 26, 2013 02:09:19 PM Oleg Nesterov wrote: > On 03/26, Rafael J. Wysocki wrote: > > > > On Thursday, March 07, 2013 06:53:59 PM Oleg Nesterov wrote: > > > hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. > > > > > > We can simply kill this mutex, hotkey_poll_stop_sync() does not need > > > to serialize with hotkey_kthread(). When kthread_stop() returns the > > > thread is already dead, it called do_exit()->complete_vfork_done(). > > > > > > Reported-by: Artem Savkov <artem.savkov@gmail.com> > > > Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> > > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > > > I wonder if anyone is taking care of this patch? > > IIRC, it is already in -mm tree. OK, thanks for letting me know. > > > --- x/drivers/platform/x86/thinkpad_acpi.c > > > +++ x/drivers/platform/x86/thinkpad_acpi.c > > > @@ -1965,9 +1965,6 @@ struct tp_nvram_state { > > > /* kthread for the hotkey poller */ > > > static struct task_struct *tpacpi_hotkey_task; > > > > > > -/* Acquired while the poller kthread is running, use to sync start/stop */ > > > -static struct mutex hotkey_thread_mutex; > > > - > > > /* > > > * Acquire mutex to write poller control variables as an > > > * atomic block. > > > @@ -2463,8 +2460,6 @@ static int hotkey_kthread(void *data) > > > unsigned int poll_freq; > > > bool was_frozen; > > > > > > - mutex_lock(&hotkey_thread_mutex); > > > - > > > if (tpacpi_lifecycle == TPACPI_LIFE_EXITING) > > > goto exit; > > > > > > @@ -2524,7 +2519,6 @@ static int hotkey_kthread(void *data) > > > } > > > > > > exit: > > > - mutex_unlock(&hotkey_thread_mutex); > > > return 0; > > > } > > > > > > @@ -2534,9 +2528,6 @@ static void hotkey_poll_stop_sync(void) > > > if (tpacpi_hotkey_task) { > > > kthread_stop(tpacpi_hotkey_task); > > > tpacpi_hotkey_task = NULL; > > > - mutex_lock(&hotkey_thread_mutex); > > > - /* at this point, the thread did exit */ > > > - mutex_unlock(&hotkey_thread_mutex); > > > } > > > } > > > > > > @@ -3235,7 +3226,6 @@ static int __init hotkey_init(struct ibm > > > mutex_init(&hotkey_mutex); > > > > > > #ifdef CONFIG_THINKPAD_ACPI_HOTKEY_POLL > > > - mutex_init(&hotkey_thread_mutex); > > > mutex_init(&hotkey_thread_data_mutex); > > > #endif > > > > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html >
--- x/drivers/platform/x86/thinkpad_acpi.c +++ x/drivers/platform/x86/thinkpad_acpi.c @@ -1965,9 +1965,6 @@ struct tp_nvram_state { /* kthread for the hotkey poller */ static struct task_struct *tpacpi_hotkey_task; -/* Acquired while the poller kthread is running, use to sync start/stop */ -static struct mutex hotkey_thread_mutex; - /* * Acquire mutex to write poller control variables as an * atomic block. @@ -2463,8 +2460,6 @@ static int hotkey_kthread(void *data) unsigned int poll_freq; bool was_frozen; - mutex_lock(&hotkey_thread_mutex); - if (tpacpi_lifecycle == TPACPI_LIFE_EXITING) goto exit; @@ -2524,7 +2519,6 @@ static int hotkey_kthread(void *data) } exit: - mutex_unlock(&hotkey_thread_mutex); return 0; } @@ -2534,9 +2528,6 @@ static void hotkey_poll_stop_sync(void) if (tpacpi_hotkey_task) { kthread_stop(tpacpi_hotkey_task); tpacpi_hotkey_task = NULL; - mutex_lock(&hotkey_thread_mutex); - /* at this point, the thread did exit */ - mutex_unlock(&hotkey_thread_mutex); } } @@ -3235,7 +3226,6 @@ static int __init hotkey_init(struct ibm mutex_init(&hotkey_mutex); #ifdef CONFIG_THINKPAD_ACPI_HOTKEY_POLL - mutex_init(&hotkey_thread_mutex); mutex_init(&hotkey_thread_data_mutex); #endif
hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. We can simply kill this mutex, hotkey_poll_stop_sync() does not need to serialize with hotkey_kthread(). When kthread_stop() returns the thread is already dead, it called do_exit()->complete_vfork_done(). Reported-by: Artem Savkov <artem.savkov@gmail.com> Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html