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From: Thomas Gleixner <tglx@linutronix.de>
To: Waiman Long <longman@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Clark Williams <clrkwllms@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev
Subject: Re: [PATCH] debugobjects: Don't call fill_pool() in early boot non-task context of RT kernel
Date: Wed, 20 May 2026 20:04:33 +0200	[thread overview]
Message-ID: <87qzn6vtxq.ffs@tglx> (raw)
In-Reply-To: <3fc2e03f-d34f-4b87-8421-e28e94247757@redhat.com>

On Wed, May 20 2026 at 12:57, Waiman Long wrote:
> On 5/20/26 12:43 PM, Waiman Long wrote:
>> It shouldn't really be a problem as fill_poll() will not called from
>> non-preemptible context after early boot, but the lockdep warning can
>> still cause confusion and anxiety. Fix that by further restricting the
>> call to only in_task() context during early boot.
>
> Sorry, the above paragraph isn't right. Will send out a v2.

And please trim the back trace while at it.

>> Fixes: 06e0ae988f6e ("debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING")
>> Signed-off-by: Waiman Long <longman@redhat.com>
>> ---
>>   lib/debugobjects.c | 7 +++++--
>>   1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/debugobjects.c b/lib/debugobjects.c
>> index 12e2e42e6a31..236ea5e716df 100644
>> --- a/lib/debugobjects.c
>> +++ b/lib/debugobjects.c
>> @@ -727,11 +727,14 @@ static void debug_objects_fill_pool(void)
>>   
>>   	/*
>>   	 * On RT enabled kernels the pool refill must happen in preemptible
>> -	 * context -- for !RT kernels we rely on the fact that spinlock_t and
>> +	 * context or in task context during early boot.
>> +	 *
>> +	 * For !RT kernels we rely on the fact that spinlock_t and
>>   	 * raw_spinlock_t are basically the same type and this lock-type
>>   	 * inversion works just fine.
>>   	 */
>> -	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() || system_state < SYSTEM_SCHEDULING) {
>> +	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() ||
>> +	   (system_state < SYSTEM_SCHEDULING && in_task())) {

Conflicts with:

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/?h=core/urgent

  reply	other threads:[~2026-05-20 18:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-20 16:43 [PATCH] debugobjects: Don't call fill_pool() in early boot non-task context of RT kernel Waiman Long
2026-05-20 16:57 ` Waiman Long
2026-05-20 18:04   ` Thomas Gleixner [this message]
2026-05-20 18:10     ` Waiman Long

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