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task_work: make TWA_NMI_CURRENT handling conditional on IRQ_WORK 

commit cec6937dd1aae1b38d147bd190cb895d06cf96d0 upstream.

The TWA_NMI_CURRENT handling very much depends on IRQ_WORK, but that
isn't universally enabled everywhere.

Maybe the IRQ_WORK infrastructure should just be unconditional - x86
ends up indirectly enabling it through unconditionally enabling
PERF_EVENTS, for example.  But it also gets enabled by having SMP
support, or even if you just have PRINTK enabled.

But in the meantime TWA_NMI_CURRENT causes tons of build failures on
various odd minimal configs.  Which did show up in linux-next, but
despite that nobody bothered to fix it or even inform me until -rc1 was
out.

Fixes: 466e4d801cd4 ("task_work: Add TWA_NMI_CURRENT as an additional notify mode")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: kernelci.org bot <bot@kernelci.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Linus Torvalds 2024-07-29 12:05:06 -07:00 committed by Greg Kroah-Hartman
parent 81507f633e
commit 7a26cb6607
1 changed files with 6 additions and 0 deletions
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6
kernel/task_work.c
View File

@ -6,12 +6,14 @@
static struct callback_head work_exited; /* all we need is ->next == NULL */
#ifdef CONFIG_IRQ_WORK
static void task_work_set_notify_irq(struct irq_work *entry)
{
test_and_set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
}
static DEFINE_PER_CPU(struct irq_work, irq_work_NMI_resume) =
IRQ_WORK_INIT_HARD(task_work_set_notify_irq);
#endif
/**
* task_work_add - ask the @task to execute @work->func()
@ -59,6 +61,8 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
if (notify == TWA_NMI_CURRENT) {
if (WARN_ON_ONCE(task != current))
return -EINVAL;
if (!IS_ENABLED(CONFIG_IRQ_WORK))
return -EINVAL;
} else {
/*
* Record the work call stack in order to print it in KASAN
@ -92,9 +96,11 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
case TWA_SIGNAL_NO_IPI:
__set_notify_signal(task);
break;
#ifdef CONFIG_IRQ_WORK
case TWA_NMI_CURRENT:
irq_work_queue(this_cpu_ptr(&irq_work_NMI_resume));
break;
#endif
default:
WARN_ON_ONCE(1);
break;