From: Zqiang Date: Thu, 13 Nov 2025 11:43:55 +0000 (+0800) Subject: sched_ext: Fix possible deadlock in the deferred_irq_workfn() X-Git-Tag: v6.18-rc7~33^2~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a257e974210320ede524f340ffe16bf4bf0dda1e;p=thirdparty%2Flinux.git sched_ext: Fix possible deadlock in the deferred_irq_workfn() For PREEMPT_RT=y kernels, the deferred_irq_workfn() is executed in the per-cpu irq_work/* task context and not disable-irq, if the rq returned by container_of() is current CPU's rq, the following scenarios may occur: lock(&rq->__lock); lock(&rq->__lock); This commit use IRQ_WORK_INIT_HARD() to replace init_irq_work() to initialize rq->scx.deferred_irq_work, make the deferred_irq_workfn() is always invoked in hard-irq context. Signed-off-by: Zqiang Signed-off-by: Tejun Heo --- diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 03d05ea20006..07399210ac2d 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -5321,7 +5321,7 @@ void __init init_sched_ext_class(void) BUG_ON(!zalloc_cpumask_var_node(&rq->scx.cpus_to_kick_if_idle, GFP_KERNEL, n)); BUG_ON(!zalloc_cpumask_var_node(&rq->scx.cpus_to_preempt, GFP_KERNEL, n)); BUG_ON(!zalloc_cpumask_var_node(&rq->scx.cpus_to_wait, GFP_KERNEL, n)); - init_irq_work(&rq->scx.deferred_irq_work, deferred_irq_workfn); + rq->scx.deferred_irq_work = IRQ_WORK_INIT_HARD(deferred_irq_workfn); init_irq_work(&rq->scx.kick_cpus_irq_work, kick_cpus_irq_workfn); if (cpu_online(cpu))