[PATCH] kthread: remove worker->task self-assignment

[PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

From: Bradley Morgan <brads@mainlining.org>

All kthread worker users now create their workers with
kthread_create_worker*(), which sets worker->task before the worker
starts. The self-assignment in kthread_worker_fn() is dead code now.

Remove it.

Signed-off-by: Bradley Morgan <brads@mainlining.org>
---
 kernel/kthread.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 63beb59b7a3d..18bc702e8d2d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
 	struct kthread_worker *worker = worker_ptr;
 	struct kthread_work *work;
 
-	/*
-	 * FIXME: Update the check and remove the assignment when all kthread
-	 * worker users are created using kthread_create_worker*() functions.
-	 */
-	WARN_ON(worker->task && worker->task != current);
-	worker->task = current;
-
 	if (worker->flags & KTW_FREEZABLE)
 		set_freezable();
 
-- 
2.47.3

[RESEND PATCH 0/5] kthread: remove worker->task self-assignment

[Bradley Morgan]

From: Bradley Morgan <brads@mainlining.org>

Resent as a proper series with cover letter. The first send went out as
five separate threads instead of one.

kthread_worker_fn() has carried a FIXME for a decade: it assigns
worker->task = current because the old kthread_run(kthread_worker_fn)
callers never told the worker what task it was. The new
kthread_create_worker*() API sets worker->task before the worker even
starts, so the self-assignment is dead code.

Four drivers were still on the old API. Convert them, then remove the
FIXME.

No functional change intended.

Bradley Morgan (5):
  media: ivtv: convert to kthread_run_worker
  net: encx24j600: convert to kthread_run_worker
  tty: sc16is7xx: convert to kthread_run_worker
  cpufreq: schedutil: convert to kthread_create_worker
  kthread: remove worker->task self-assignment

 drivers/media/pci/ivtv/ivtv-driver.c    | 11 ++++-------
 drivers/media/pci/ivtv/ivtv-driver.h    |  3 +--
 drivers/net/ethernet/microchip/encx24j600.c | 12 ++++--------
 drivers/tty/serial/sc16is7xx.c        | 17 +++++++----------
 kernel/sched/cpufreq_schedutil.c       | 14 +++++--------
 kernel/kthread.c                      |  7 -------
 6 files changed, 21 insertions(+), 63 deletions(-)

[PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

From: Bradley Morgan <brads@mainlining.org>

All kthread worker users now create their workers with
kthread_create_worker*(), which sets worker->task before the worker
starts. The self-assignment in kthread_worker_fn() is dead code now.

Remove it.

Signed-off-by: Bradley Morgan <brads@mainlining.org>
---
 kernel/kthread.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 63beb59b7a3d..18bc702e8d2d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
 	struct kthread_worker *worker = worker_ptr;
 	struct kthread_work *work;
 
-	/*
-	 * FIXME: Update the check and remove the assignment when all kthread
-	 * worker users are created using kthread_create_worker*() functions.
-	 */
-	WARN_ON(worker->task && worker->task != current);
-	worker->task = current;
-
 	if (worker->flags & KTW_FREEZABLE)
 		set_freezable();
 
-- 
2.47.3

Re: [PATCH] kthread: remove worker->task self-assignment

[Frederic Weisbecker]

Hi,

Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
> From: Bradley Morgan <brads@mainlining.org>
> 
> All kthread worker users now create their workers with
> kthread_create_worker*(), which sets worker->task before the worker
> starts. The self-assignment in kthread_worker_fn() is dead code now.

How could it be created before?

> 
> Remove it.
> 
> Signed-off-by: Bradley Morgan <brads@mainlining.org>
> ---
>  kernel/kthread.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/kernel/kthread.c b/kernel/kthread.c
> index 63beb59b7a3d..18bc702e8d2d 100644
> --- a/kernel/kthread.c
> +++ b/kernel/kthread.c
> @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
>  	struct kthread_worker *worker = worker_ptr;
>  	struct kthread_work *work;
>  
> -	/*
> -	 * FIXME: Update the check and remove the assignment when all kthread
> -	 * worker users are created using kthread_create_worker*() functions.
> -	 */
> -	WARN_ON(worker->task && worker->task != current);

Should we keep a WARN_ON(worker->task != current) here?

Thanks.

> -	worker->task = current;
> -
>  	if (worker->flags & KTW_FREEZABLE)
>  		set_freezable();
>  
> -- 
> 2.47.3

-- 
Frederic Weisbecker
SUSE Labs

Re: [PATCH] kthread: remove worker->task self-assignment

[Peter Zijlstra]

On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
> Hi,
> 
> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
> > From: Bradley Morgan <brads@mainlining.org>
> > 
> > All kthread worker users now create their workers with
> > kthread_create_worker*(), which sets worker->task before the worker
> > starts. The self-assignment in kthread_worker_fn() is dead code now.
> 
> How could it be created before?
> 
> > 
> > Remove it.
> > 
> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
> > ---
> >  kernel/kthread.c | 7 -------
> >  1 file changed, 7 deletions(-)
> > 
> > diff --git a/kernel/kthread.c b/kernel/kthread.c
> > index 63beb59b7a3d..18bc702e8d2d 100644
> > --- a/kernel/kthread.c
> > +++ b/kernel/kthread.c
> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
> >  	struct kthread_worker *worker = worker_ptr;
> >  	struct kthread_work *work;
> >  
> > -	/*
> > -	 * FIXME: Update the check and remove the assignment when all kthread
> > -	 * worker users are created using kthread_create_worker*() functions.
> > -	 */
> > -	WARN_ON(worker->task && worker->task != current);
> 
> Should we keep a WARN_ON(worker->task != current) here?

I vote yes! Paranoia is good :-)

Re: [PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
wrote:
>On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
>> Hi,
>> 
>> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
>> > From: Bradley Morgan <brads@mainlining.org>
>> > 
>> > All kthread worker users now create their workers with
>> > kthread_create_worker*(), which sets worker->task before the worker
>> > starts. The self-assignment in kthread_worker_fn() is dead code now.
>> 
>> How could it be created before?
>> 
>> > 
>> > Remove it.
>> > 
>> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
>> > ---
>> >  kernel/kthread.c | 7 -------
>> >  1 file changed, 7 deletions(-)
>> > 
>> > diff --git a/kernel/kthread.c b/kernel/kthread.c
>> > index 63beb59b7a3d..18bc702e8d2d 100644
>> > --- a/kernel/kthread.c
>> > +++ b/kernel/kthread.c
>> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
>> >  	struct kthread_worker *worker = worker_ptr;
>> >  	struct kthread_work *work;
>> >  
>> > -	/*
>> > -	 * FIXME: Update the check and remove the assignment when all kthread
>> > -	 * worker users are created using kthread_create_worker*() functions.
>> > -	 */
>> > -	WARN_ON(worker->task && worker->task != current);
>> 
>> Should we keep a WARN_ON(worker->task != current) here?
>
>I vote yes! Paranoia is good :-)
>


Yeah, but it *should* be useless. Do you really want me to readd the warn
statement? Maybe add some text, like

"worker->task is deprecated"?

--- Thanks!
https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

Re: [PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

On 1 September 2026 14:57:38 BST, Bradley Morgan <brads@mainlining.org>
wrote:
>On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
>wrote:
>>On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
>>> Hi,
>>> 
>>> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
>>> > From: Bradley Morgan <brads@mainlining.org>
>>> > 
>>> > All kthread worker users now create their workers with
>>> > kthread_create_worker*(), which sets worker->task before the worker
>>> > starts. The self-assignment in kthread_worker_fn() is dead code now.
>>> 
>>> How could it be created before?
>>> 
>>> > 
>>> > Remove it.
>>> > 
>>> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
>>> > ---
>>> >  kernel/kthread.c | 7 -------
>>> >  1 file changed, 7 deletions(-)
>>> > 
>>> > diff --git a/kernel/kthread.c b/kernel/kthread.c
>>> > index 63beb59b7a3d..18bc702e8d2d 100644
>>> > --- a/kernel/kthread.c
>>> > +++ b/kernel/kthread.c
>>> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
>>> >  	struct kthread_worker *worker = worker_ptr;
>>> >  	struct kthread_work *work;
>>> >  
>>> > -	/*
>>> > -	 * FIXME: Update the check and remove the assignment when all kthread
>>> > -	 * worker users are created using kthread_create_worker*() functions.
>>> > -	 */
>>> > -	WARN_ON(worker->task && worker->task != current);
>>> 
>>> Should we keep a WARN_ON(worker->task != current) here?
>>
>>I vote yes! Paranoia is good :-)
>>
>
>
>Yeah, but it *should* be useless. Do you really want me to readd the warn
>statement? Maybe add some text, like
>
>"worker->task is deprecated"?

Btw this is a "something around the lines of", so it's definitely not
gonna be this! (Its sorta wrong too)

>
>--- Thanks!
>https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

--- Thanks!
https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

Re: [PATCH] kthread: remove worker->task self-assignment

[Frederic Weisbecker]

Le Tue, Sep 01, 2026 at 02:57:38PM +0100, Bradley Morgan a écrit :
> On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
> wrote:
> >On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
> >> Hi,
> >> 
> >> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
> >> > From: Bradley Morgan <brads@mainlining.org>
> >> > 
> >> > All kthread worker users now create their workers with
> >> > kthread_create_worker*(), which sets worker->task before the worker
> >> > starts. The self-assignment in kthread_worker_fn() is dead code now.
> >> 
> >> How could it be created before?
> >> 
> >> > 
> >> > Remove it.
> >> > 
> >> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
> >> > ---
> >> >  kernel/kthread.c | 7 -------
> >> >  1 file changed, 7 deletions(-)
> >> > 
> >> > diff --git a/kernel/kthread.c b/kernel/kthread.c
> >> > index 63beb59b7a3d..18bc702e8d2d 100644
> >> > --- a/kernel/kthread.c
> >> > +++ b/kernel/kthread.c
> >> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
> >> >  	struct kthread_worker *worker = worker_ptr;
> >> >  	struct kthread_work *work;
> >> >  
> >> > -	/*
> >> > -	 * FIXME: Update the check and remove the assignment when all kthread
> >> > -	 * worker users are created using kthread_create_worker*() functions.
> >> > -	 */
> >> > -	WARN_ON(worker->task && worker->task != current);
> >> 
> >> Should we keep a WARN_ON(worker->task != current) here?
> >
> >I vote yes! Paranoia is good :-)
> >
> 
> 
> Yeah, but it *should* be useless.

Famous last words :-)

> Do you really want me to readd the warn
> statement? Maybe add some text, like
> 
> "worker->task is deprecated"?

Is it deprecated? We still need that field for wakeup on queue at least.
Don't bother with a message, it's only a sanity check.

Thanks.

> 
> --- Thanks!
> https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

-- 
Frederic Weisbecker
SUSE Labs

Re: [PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

On 1 September 2026 15:06:51 BST, Frederic Weisbecker <frederic@kernel.org>
wrote:
>Le Tue, Sep 01, 2026 at 02:57:38PM +0100, Bradley Morgan a écrit :
>> On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
>> wrote:
>> >On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
>> >> Hi,
>> >> 
>> >> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
>> >> > From: Bradley Morgan <brads@mainlining.org>
>> >> > 
>> >> > All kthread worker users now create their workers with
>> >> > kthread_create_worker*(), which sets worker->task before the worker
>> >> > starts. The self-assignment in kthread_worker_fn() is dead code
>now.
>> >> 
>> >> How could it be created before?
>> >> 
>> >> > 
>> >> > Remove it.
>> >> > 
>> >> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
>> >> > ---
>> >> >  kernel/kthread.c | 7 -------
>> >> >  1 file changed, 7 deletions(-)
>> >> > 
>> >> > diff --git a/kernel/kthread.c b/kernel/kthread.c
>> >> > index 63beb59b7a3d..18bc702e8d2d 100644
>> >> > --- a/kernel/kthread.c
>> >> > +++ b/kernel/kthread.c
>> >> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
>> >> >  	struct kthread_worker *worker = worker_ptr;
>> >> >  	struct kthread_work *work;
>> >> >  
>> >> > -	/*
>> >> > -	 * FIXME: Update the check and remove the assignment when all kthread
>> >> > -	 * worker users are created using kthread_create_worker*() functions.
>> >> > -	 */
>> >> > -	WARN_ON(worker->task && worker->task != current);
>> >> 
>> >> Should we keep a WARN_ON(worker->task != current) here?
>> >
>> >I vote yes! Paranoia is good :-)
>> >
>> 
>> 
>> Yeah, but it *should* be useless.
>
>Famous last words :-)
>

Hahahaha

>> Do you really want me to readd the warn
>> statement? Maybe add some text, like
>> 
>> "worker->task is deprecated"?
>
>Is it deprecated? We still need that field for wakeup on queue at least.
>Don't bother with a message, it's only a sanity check.

Okie, I did convert all the drivers as you can see, if you wanna give it a
lookie

>
>Thanks.
>
>> 
>> --- Thanks!
>>
>https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/
>
>

--- Thanks!
https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

Re: [PATCH] kthread: remove worker->task self-assignment

[Frederic Weisbecker]

Le Tue, Sep 01, 2026 at 03:09:03PM +0100, Bradley Morgan a écrit :
> On 1 September 2026 15:06:51 BST, Frederic Weisbecker <frederic@kernel.org>
> wrote:
> >Le Tue, Sep 01, 2026 at 02:57:38PM +0100, Bradley Morgan a écrit :
> >> On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
> >> wrote:
> >> >On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
> >> >> Hi,
> >> >> 
> >> >> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
> >> >> > From: Bradley Morgan <brads@mainlining.org>
> >> >> > 
> >> >> > All kthread worker users now create their workers with
> >> >> > kthread_create_worker*(), which sets worker->task before the worker
> >> >> > starts. The self-assignment in kthread_worker_fn() is dead code
> >now.
> >> >> 
> >> >> How could it be created before?
> >> >> 
> >> >> > 
> >> >> > Remove it.
> >> >> > 
> >> >> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
> >> >> > ---
> >> >> >  kernel/kthread.c | 7 -------
> >> >> >  1 file changed, 7 deletions(-)
> >> >> > 
> >> >> > diff --git a/kernel/kthread.c b/kernel/kthread.c
> >> >> > index 63beb59b7a3d..18bc702e8d2d 100644
> >> >> > --- a/kernel/kthread.c
> >> >> > +++ b/kernel/kthread.c
> >> >> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
> >> >> >  	struct kthread_worker *worker = worker_ptr;
> >> >> >  	struct kthread_work *work;
> >> >> >  
> >> >> > -	/*
> >> >> > -	 * FIXME: Update the check and remove the assignment when all kthread
> >> >> > -	 * worker users are created using kthread_create_worker*() functions.
> >> >> > -	 */
> >> >> > -	WARN_ON(worker->task && worker->task != current);
> >> >> 
> >> >> Should we keep a WARN_ON(worker->task != current) here?
> >> >
> >> >I vote yes! Paranoia is good :-)
> >> >
> >> 
> >> 
> >> Yeah, but it *should* be useless.
> >
> >Famous last words :-)
> >
> 
> Hahahaha
> 
> >> Do you really want me to readd the warn
> >> statement? Maybe add some text, like
> >> 
> >> "worker->task is deprecated"?
> >
> >Is it deprecated? We still need that field for wakeup on queue at least.
> >Don't bother with a message, it's only a sanity check.
> 
> Okie, I did convert all the drivers as you can see, if you wanna give it a
> lookie

Do you have a link to that?

Thanks.

> 
> >
> >Thanks.
> >
> >> 
> >> --- Thanks!
> >>
> >https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/
> >
> >
> 
> --- Thanks!
> https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

-- 
Frederic Weisbecker
SUSE Labs

Re: [PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

On 2 September 2026 15:09:05 BST, Frederic Weisbecker <frederic@kernel.org>
wrote:
>Le Tue, Sep 01, 2026 at 03:09:03PM +0100, Bradley Morgan a écrit :
>> On 1 September 2026 15:06:51 BST, Frederic Weisbecker
><frederic@kernel.org>
>> wrote:
>> >Le Tue, Sep 01, 2026 at 02:57:38PM +0100, Bradley Morgan a écrit :
>> >> On 1 September 2026 13:49:00 BST, Peter Zijlstra
><peterz@infradead.org>
>> >> wrote:
>> >> >On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
>> >> >> Hi,
>> >> >> 
>> >> >> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
>> >> >> > From: Bradley Morgan <brads@mainlining.org>
>> >> >> > 
>> >> >> > All kthread worker users now create their workers with
>> >> >> > kthread_create_worker*(), which sets worker->task before the
>worker
>> >> >> > starts. The self-assignment in kthread_worker_fn() is dead code
>> >now.
>> >> >> 
>> >> >> How could it be created before?
>> >> >> 
>> >> >> > 
>> >> >> > Remove it.
>> >> >> > 
>> >> >> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
>> >> >> > ---
>> >> >> >  kernel/kthread.c | 7 -------
>> >> >> >  1 file changed, 7 deletions(-)
>> >> >> > 
>> >> >> > diff --git a/kernel/kthread.c b/kernel/kthread.c
>> >> >> > index 63beb59b7a3d..18bc702e8d2d 100644
>> >> >> > --- a/kernel/kthread.c
>> >> >> > +++ b/kernel/kthread.c
>> >> >> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
>> >> >> >  	struct kthread_worker *worker = worker_ptr;
>> >> >> >  	struct kthread_work *work;
>> >> >> >  
>> >> >> > -	/*
>> >> >> > -	 * FIXME: Update the check and remove the assignment when all kthread
>> >> >> > -	 * worker users are created using kthread_create_worker*() functions.
>> >> >> > -	 */
>> >> >> > -	WARN_ON(worker->task && worker->task != current);
>> >> >> 
>> >> >> Should we keep a WARN_ON(worker->task != current) here?
>> >> >
>> >> >I vote yes! Paranoia is good :-)
>> >> >
>> >> 
>> >> 
>> >> Yeah, but it *should* be useless.
>> >
>> >Famous last words :-)
>> >
>> 
>> Hahahaha
>> 
>> >> Do you really want me to readd the warn
>> >> statement? Maybe add some text, like
>> >> 
>> >> "worker->task is deprecated"?
>> >
>> >Is it deprecated? We still need that field for wakeup on queue at
>least.
>> >Don't bother with a message, it's only a sanity check.
>> 
>> Okie, I did convert all the drivers as you can see, if you wanna give it
>a
>> lookie
>
>Do you have a link to that?
>
>Thanks.

uhh, they should be all in-reply-tos, so if you search for my series in
lore, this patch replies to all of the conversions




>
>> 
>> >
>> >Thanks.
>> >
>> >> 
>> >> --- Thanks!
>> >>
>>
>>https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/
>> >
>> >
>> 
>> --- Thanks!
>>
>https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/
>
>

--- Thanks!
https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

Re: [PATCH] kthread: remove worker->task self-assignment

[Bradley Morgan]

On 1 September 2026 15:06:51 BST, Frederic Weisbecker <frederic@kernel.org>
wrote:
>Le Tue, Sep 01, 2026 at 02:57:38PM +0100, Bradley Morgan a écrit :
>> On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
>> wrote:
>> >On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
>> >> Hi,
>> >> 
>> >> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
>> >> > From: Bradley Morgan <brads@mainlining.org>
>> >> > 
>> >> > All kthread worker users now create their workers with
>> >> > kthread_create_worker*(), which sets worker->task before the worker
>> >> > starts. The self-assignment in kthread_worker_fn() is dead code
>now.
>> >> 
>> >> How could it be created before?
>> >> 
>> >> > 
>> >> > Remove it.
>> >> > 
>> >> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
>> >> > ---
>> >> >  kernel/kthread.c | 7 -------
>> >> >  1 file changed, 7 deletions(-)
>> >> > 
>> >> > diff --git a/kernel/kthread.c b/kernel/kthread.c
>> >> > index 63beb59b7a3d..18bc702e8d2d 100644
>> >> > --- a/kernel/kthread.c
>> >> > +++ b/kernel/kthread.c
>> >> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
>> >> >  	struct kthread_worker *worker = worker_ptr;
>> >> >  	struct kthread_work *work;
>> >> >  
>> >> > -	/*
>> >> > -	 * FIXME: Update the check and remove the assignment when all kthread
>> >> > -	 * worker users are created using kthread_create_worker*() functions.
>> >> > -	 */
>> >> > -	WARN_ON(worker->task && worker->task != current);
>> >> 
>> >> Should we keep a WARN_ON(worker->task != current) here?
>> >
>> >I vote yes! Paranoia is good :-)
>> >
>> 
>> 
>> Yeah, but it *should* be useless.
>
>Famous last words :-)
>
>> Do you really want me to readd the warn
>> statement? Maybe add some text, like
>> 
>> "worker->task is deprecated"?
>
>Is it deprecated? We still need that field for wakeup on queue at least.
>Don't bother with a message, it's only a sanity check.
>
>Thanks.

Hi, I hopped on the computer, 

Right, so the whole warn on things is good, but I converted all the
callers, so it'll never fire.

For OOT users, maybe this'll be beneficial (but yk what their like, theyll
remove the warn on)

Guys, what do you think?

>
>> 
>> --- Thanks!
>>
>https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/
>
>

--- Thanks!
https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

Re: [PATCH] kthread: remove worker->task self-assignment

[Frederic Weisbecker]

Le Tue, Sep 01, 2026 at 07:28:19PM +0100, Bradley Morgan a écrit :
> On 1 September 2026 15:06:51 BST, Frederic Weisbecker <frederic@kernel.org>
> wrote:
> >Le Tue, Sep 01, 2026 at 02:57:38PM +0100, Bradley Morgan a écrit :
> >> On 1 September 2026 13:49:00 BST, Peter Zijlstra <peterz@infradead.org>
> >> wrote:
> >> >On Tue, Sep 01, 2026 at 02:45:43PM +0200, Frederic Weisbecker wrote:
> >> >> Hi,
> >> >> 
> >> >> Le Sat, Aug 29, 2026 at 04:18:48PM +0000, Bradley Morgan a écrit :
> >> >> > From: Bradley Morgan <brads@mainlining.org>
> >> >> > 
> >> >> > All kthread worker users now create their workers with
> >> >> > kthread_create_worker*(), which sets worker->task before the worker
> >> >> > starts. The self-assignment in kthread_worker_fn() is dead code
> >now.
> >> >> 
> >> >> How could it be created before?
> >> >> 
> >> >> > 
> >> >> > Remove it.
> >> >> > 
> >> >> > Signed-off-by: Bradley Morgan <brads@mainlining.org>
> >> >> > ---
> >> >> >  kernel/kthread.c | 7 -------
> >> >> >  1 file changed, 7 deletions(-)
> >> >> > 
> >> >> > diff --git a/kernel/kthread.c b/kernel/kthread.c
> >> >> > index 63beb59b7a3d..18bc702e8d2d 100644
> >> >> > --- a/kernel/kthread.c
> >> >> > +++ b/kernel/kthread.c
> >> >> > @@ -987,13 +987,6 @@ int kthread_worker_fn(void *worker_ptr)
> >> >> >  	struct kthread_worker *worker = worker_ptr;
> >> >> >  	struct kthread_work *work;
> >> >> >  
> >> >> > -	/*
> >> >> > -	 * FIXME: Update the check and remove the assignment when all kthread
> >> >> > -	 * worker users are created using kthread_create_worker*() functions.
> >> >> > -	 */
> >> >> > -	WARN_ON(worker->task && worker->task != current);
> >> >> 
> >> >> Should we keep a WARN_ON(worker->task != current) here?
> >> >
> >> >I vote yes! Paranoia is good :-)
> >> >
> >> 
> >> 
> >> Yeah, but it *should* be useless.
> >
> >Famous last words :-)
> >
> >> Do you really want me to readd the warn
> >> statement? Maybe add some text, like
> >> 
> >> "worker->task is deprecated"?
> >
> >Is it deprecated? We still need that field for wakeup on queue at least.
> >Don't bother with a message, it's only a sanity check.
> >
> >Thanks.
> 
> Hi, I hopped on the computer, 
> 
> Right, so the whole warn on things is good, but I converted all the
> callers, so it'll never fire.
> 
> For OOT users, maybe this'll be beneficial (but yk what their like, theyll
> remove the warn on)
> 
> Guys, what do you think?

The warning is mostly to prevent from future changes to break.

Thanks.

> 
> >
> >> 
> >> --- Thanks!
> >>
> >https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/
> >
> >
> 
> --- Thanks!
> https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/

-- 
Frederic Weisbecker
SUSE Labs