| Message ID | 892bb009-4ba8-15fa-c8f9-eb66ab75b2f0@I-love.SAKURA.ne.jp (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ACPI: Avoid flush_scheduled_work() usage | expand |
On Tue, Apr 19, 2022 at 3:57 PM Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: > > Flushing system-wide workqueues is dangerous and will be forbidden. > Replace system_wq with local acpi_wq. > > Link: https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > --- > This patch blindly converts schedule_{,rcu_}work() into queue_{,rcu_}work() > within drivers/acpi/ directory, based on an assumption that none of work items > outside of drivers/acpi/ directory needs to be handled by acpi_wq. > Also, I kept sharing acpi_wq between acpi/ and acpi/apei, based on assumption > that sharing is safe and correct behavior. Did I convert correctly? Please don't do it this way. There is not much sense in sharing a dedicated workqueue between the different pieces of code below. I guess that there is a need to switch over to dedicated workqueues in all cases when the workqueue needs to be flushed directly. If so, please let me look at what can be done. > > drivers/acpi/acpi_video.c | 2 +- > drivers/acpi/apei/apei-internal.h | 1 + > drivers/acpi/apei/ghes.c | 2 +- > drivers/acpi/bus.c | 2 +- > drivers/acpi/internal.h | 1 + > drivers/acpi/osl.c | 6 +++++- > drivers/acpi/scan.c | 2 +- > drivers/acpi/video_detect.c | 2 +- > 8 files changed, 12 insertions(+), 6 deletions(-) > > diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c > index 990ff5b0aeb8..18a5b8dd766e 100644 > --- a/drivers/acpi/acpi_video.c > +++ b/drivers/acpi/acpi_video.c > @@ -1637,7 +1637,7 @@ static void brightness_switch_event(struct acpi_video_device *video_device, > return; > > video_device->switch_brightness_event = event; > - schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10); > + queue_delayed_work(acpi_wq, &video_device->switch_brightness_work, HZ / 10); > } > > static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data) > diff --git a/drivers/acpi/apei/apei-internal.h b/drivers/acpi/apei/apei-internal.h > index 1d6ef9654725..205dcacf8abf 100644 > --- a/drivers/acpi/apei/apei-internal.h > +++ b/drivers/acpi/apei/apei-internal.h > @@ -136,4 +136,5 @@ int cper_estatus_check_header(const struct acpi_hest_generic_status *estatus); > int cper_estatus_check(const struct acpi_hest_generic_status *estatus); > > int apei_osc_setup(void); > +extern struct workqueue_struct *acpi_wq; > #endif > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c > index d91ad378c00d..871b5f6c2b45 100644 > --- a/drivers/acpi/apei/ghes.c > +++ b/drivers/acpi/apei/ghes.c > @@ -619,7 +619,7 @@ static void ghes_defer_non_standard_event(struct acpi_hest_generic_data *gdata, > entry->error_severity = sev; > > INIT_WORK(&entry->work, ghes_vendor_record_work_func); > - schedule_work(&entry->work); > + queue_work(acpi_wq, &entry->work); > } > > static bool ghes_do_proc(struct ghes *ghes, > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c > index e807bffc0804..7dae7f884187 100644 > --- a/drivers/acpi/bus.c > +++ b/drivers/acpi/bus.c > @@ -608,7 +608,7 @@ static void acpi_sb_notify(acpi_handle handle, u32 event, void *data) > > if (event == ACPI_SB_NOTIFY_SHUTDOWN_REQUEST) { > if (!work_busy(&acpi_sb_work)) > - schedule_work(&acpi_sb_work); > + queue_work(acpi_wq, &acpi_sb_work); > } else > pr_warn("event %x is not supported by \\_SB device\n", event); > } > diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h > index 628bf8f18130..5f77c7c573a6 100644 > --- a/drivers/acpi/internal.h > +++ b/drivers/acpi/internal.h > @@ -77,6 +77,7 @@ void acpi_lpss_init(void); > #else > static inline void acpi_lpss_init(void) {} > #endif > +extern struct workqueue_struct *acpi_wq; > > void acpi_apd_init(void); > > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c > index 7a70c4bfc23c..1725125890cd 100644 > --- a/drivers/acpi/osl.c > +++ b/drivers/acpi/osl.c > @@ -64,6 +64,7 @@ static int (*__acpi_os_prepare_extended_sleep)(u8 sleep_state, u32 val_a, > > static acpi_osd_handler acpi_irq_handler; > static void *acpi_irq_context; > +struct workqueue_struct *acpi_wq; > static struct workqueue_struct *kacpid_wq; > static struct workqueue_struct *kacpi_notify_wq; > static struct workqueue_struct *kacpi_hotplug_wq; > @@ -1575,7 +1576,7 @@ acpi_status acpi_release_memory(acpi_handle handle, struct resource *res, > */ > synchronize_rcu(); > rcu_barrier(); > - flush_scheduled_work(); > + flush_workqueue(acpi_wq); > > return AE_OK; > } > @@ -1755,9 +1756,11 @@ acpi_status __init acpi_os_initialize(void) > > acpi_status __init acpi_os_initialize1(void) > { > + acpi_wq = alloc_workqueue("acpi", 0, 0); > kacpid_wq = alloc_workqueue("kacpid", 0, 1); > kacpi_notify_wq = alloc_workqueue("kacpi_notify", 0, 1); > kacpi_hotplug_wq = alloc_ordered_workqueue("kacpi_hotplug", 0); > + BUG_ON(!acpi_wq); > BUG_ON(!kacpid_wq); > BUG_ON(!kacpi_notify_wq); > BUG_ON(!kacpi_hotplug_wq); > @@ -1786,6 +1789,7 @@ acpi_status acpi_os_terminate(void) > destroy_workqueue(kacpid_wq); > destroy_workqueue(kacpi_notify_wq); > destroy_workqueue(kacpi_hotplug_wq); > + destroy_workqueue(acpi_wq); > > return AE_OK; > } > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 762b61f67e6c..f16aaec445f2 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -2676,7 +2676,7 @@ void acpi_scan_table_notify(void) > return; > > INIT_WORK(work, acpi_table_events_fn); > - schedule_work(work); > + queue_work(acpi_wq, work); > } > > int acpi_reconfig_notifier_register(struct notifier_block *nb) > diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c > index becc198e4c22..441664275645 100644 > --- a/drivers/acpi/video_detect.c > +++ b/drivers/acpi/video_detect.c > @@ -529,7 +529,7 @@ static int acpi_video_backlight_notify(struct notifier_block *nb, > /* A raw bl registering may change video -> native */ > if (backlight->props.type == BACKLIGHT_RAW && > val == BACKLIGHT_REGISTERED) > - schedule_work(&backlight_notify_work); > + queue_work(acpi_wq, &backlight_notify_work); > > return NOTIFY_OK; > } > -- > 2.32.0 >
On 2022/04/19 23:48, Rafael J. Wysocki wrote: > On Tue, Apr 19, 2022 at 3:57 PM Tetsuo Handa > <penguin-kernel@i-love.sakura.ne.jp> wrote: >> >> Flushing system-wide workqueues is dangerous and will be forbidden. >> Replace system_wq with local acpi_wq. >> >> Link: https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp >> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> >> --- >> This patch blindly converts schedule_{,rcu_}work() into queue_{,rcu_}work() >> within drivers/acpi/ directory, based on an assumption that none of work items >> outside of drivers/acpi/ directory needs to be handled by acpi_wq. >> Also, I kept sharing acpi_wq between acpi/ and acpi/apei, based on assumption >> that sharing is safe and correct behavior. Did I convert correctly? > > Please don't do it this way. > > There is not much sense in sharing a dedicated workqueue between the > different pieces of code below. > > I guess that there is a need to switch over to dedicated workqueues in > all cases when the workqueue needs to be flushed directly. If so, > please let me look at what can be done. > Since system_wq is shared throughout the kernel, calling flush_scheduled_work() might cause deadlock. In order to avoid possibility of deadlock, there is a need to use a dedicated workqueue in all cases when some work is subjected to flush_workqueue(). This is one of patches for avoiding flush_scheduled_work() usage, but I'm not familiar with ACPI code. Thus, please introduce a dedicated workqueue in a way you think makes sense.
Hi Tetsuo,
I love your patch! Yet something to improve:
[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on v5.18-rc3 next-20220419]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Tetsuo-Handa/ACPI-Avoid-flush_scheduled_work-usage/20220419-215854
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: i386-randconfig-a013 (https://download.01.org/0day-ci/archive/20220420/202204200917.Gi0wjcgM-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c1c49a356162b22554088d269f7689bdb044a9f1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/cebc6c01f6fac86f7deaf74ca81311d9c3d179f4
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Tetsuo-Handa/ACPI-Avoid-flush_scheduled_work-usage/20220419-215854
git checkout cebc6c01f6fac86f7deaf74ca81311d9c3d179f4
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> drivers/acpi/acpi_video.c:1640:21: error: use of undeclared identifier 'acpi_wq'
queue_delayed_work(acpi_wq, &video_device->switch_brightness_work, HZ / 10);
^
drivers/acpi/acpi_video.c:2258:6: warning: no previous prototype for function 'acpi_video_unregister_backlight' [-Wmissing-prototypes]
void acpi_video_unregister_backlight(void)
^
drivers/acpi/acpi_video.c:2258:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void acpi_video_unregister_backlight(void)
^
static
1 warning and 1 error generated.
--
>> drivers/acpi/video_detect.c:532:14: error: use of undeclared identifier 'acpi_wq'
queue_work(acpi_wq, &backlight_notify_work);
^
drivers/acpi/video_detect.c:605:13: warning: no previous prototype for function 'acpi_video_detect_exit' [-Wmissing-prototypes]
void __exit acpi_video_detect_exit(void)
^
drivers/acpi/video_detect.c:605:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void __exit acpi_video_detect_exit(void)
^
static
1 warning and 1 error generated.
vim +/acpi_wq +1640 drivers/acpi/acpi_video.c
1632
1633 static void brightness_switch_event(struct acpi_video_device *video_device,
1634 u32 event)
1635 {
1636 if (!brightness_switch_enabled)
1637 return;
1638
1639 video_device->switch_brightness_event = event;
> 1640 queue_delayed_work(acpi_wq, &video_device->switch_brightness_work, HZ / 10);
1641 }
1642
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index 990ff5b0aeb8..18a5b8dd766e 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -1637,7 +1637,7 @@ static void brightness_switch_event(struct acpi_video_device *video_device, return; video_device->switch_brightness_event = event; - schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10); + queue_delayed_work(acpi_wq, &video_device->switch_brightness_work, HZ / 10); } static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data) diff --git a/drivers/acpi/apei/apei-internal.h b/drivers/acpi/apei/apei-internal.h index 1d6ef9654725..205dcacf8abf 100644 --- a/drivers/acpi/apei/apei-internal.h +++ b/drivers/acpi/apei/apei-internal.h @@ -136,4 +136,5 @@ int cper_estatus_check_header(const struct acpi_hest_generic_status *estatus); int cper_estatus_check(const struct acpi_hest_generic_status *estatus); int apei_osc_setup(void); +extern struct workqueue_struct *acpi_wq; #endif diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index d91ad378c00d..871b5f6c2b45 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -619,7 +619,7 @@ static void ghes_defer_non_standard_event(struct acpi_hest_generic_data *gdata, entry->error_severity = sev; INIT_WORK(&entry->work, ghes_vendor_record_work_func); - schedule_work(&entry->work); + queue_work(acpi_wq, &entry->work); } static bool ghes_do_proc(struct ghes *ghes, diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index e807bffc0804..7dae7f884187 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -608,7 +608,7 @@ static void acpi_sb_notify(acpi_handle handle, u32 event, void *data) if (event == ACPI_SB_NOTIFY_SHUTDOWN_REQUEST) { if (!work_busy(&acpi_sb_work)) - schedule_work(&acpi_sb_work); + queue_work(acpi_wq, &acpi_sb_work); } else pr_warn("event %x is not supported by \\_SB device\n", event); } diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 628bf8f18130..5f77c7c573a6 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -77,6 +77,7 @@ void acpi_lpss_init(void); #else static inline void acpi_lpss_init(void) {} #endif +extern struct workqueue_struct *acpi_wq; void acpi_apd_init(void); diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 7a70c4bfc23c..1725125890cd 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -64,6 +64,7 @@ static int (*__acpi_os_prepare_extended_sleep)(u8 sleep_state, u32 val_a, static acpi_osd_handler acpi_irq_handler; static void *acpi_irq_context; +struct workqueue_struct *acpi_wq; static struct workqueue_struct *kacpid_wq; static struct workqueue_struct *kacpi_notify_wq; static struct workqueue_struct *kacpi_hotplug_wq; @@ -1575,7 +1576,7 @@ acpi_status acpi_release_memory(acpi_handle handle, struct resource *res, */ synchronize_rcu(); rcu_barrier(); - flush_scheduled_work(); + flush_workqueue(acpi_wq); return AE_OK; } @@ -1755,9 +1756,11 @@ acpi_status __init acpi_os_initialize(void) acpi_status __init acpi_os_initialize1(void) { + acpi_wq = alloc_workqueue("acpi", 0, 0); kacpid_wq = alloc_workqueue("kacpid", 0, 1); kacpi_notify_wq = alloc_workqueue("kacpi_notify", 0, 1); kacpi_hotplug_wq = alloc_ordered_workqueue("kacpi_hotplug", 0); + BUG_ON(!acpi_wq); BUG_ON(!kacpid_wq); BUG_ON(!kacpi_notify_wq); BUG_ON(!kacpi_hotplug_wq); @@ -1786,6 +1789,7 @@ acpi_status acpi_os_terminate(void) destroy_workqueue(kacpid_wq); destroy_workqueue(kacpi_notify_wq); destroy_workqueue(kacpi_hotplug_wq); + destroy_workqueue(acpi_wq); return AE_OK; } diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 762b61f67e6c..f16aaec445f2 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -2676,7 +2676,7 @@ void acpi_scan_table_notify(void) return; INIT_WORK(work, acpi_table_events_fn); - schedule_work(work); + queue_work(acpi_wq, work); } int acpi_reconfig_notifier_register(struct notifier_block *nb) diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index becc198e4c22..441664275645 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -529,7 +529,7 @@ static int acpi_video_backlight_notify(struct notifier_block *nb, /* A raw bl registering may change video -> native */ if (backlight->props.type == BACKLIGHT_RAW && val == BACKLIGHT_REGISTERED) - schedule_work(&backlight_notify_work); + queue_work(acpi_wq, &backlight_notify_work); return NOTIFY_OK; }
Flushing system-wide workqueues is dangerous and will be forbidden. Replace system_wq with local acpi_wq. Link: https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- This patch blindly converts schedule_{,rcu_}work() into queue_{,rcu_}work() within drivers/acpi/ directory, based on an assumption that none of work items outside of drivers/acpi/ directory needs to be handled by acpi_wq. Also, I kept sharing acpi_wq between acpi/ and acpi/apei, based on assumption that sharing is safe and correct behavior. Did I convert correctly? drivers/acpi/acpi_video.c | 2 +- drivers/acpi/apei/apei-internal.h | 1 + drivers/acpi/apei/ghes.c | 2 +- drivers/acpi/bus.c | 2 +- drivers/acpi/internal.h | 1 + drivers/acpi/osl.c | 6 +++++- drivers/acpi/scan.c | 2 +- drivers/acpi/video_detect.c | 2 +- 8 files changed, 12 insertions(+), 6 deletions(-)