diff options
Diffstat (limited to 'features/rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch')
| -rw-r--r-- | features/rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/features/rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch b/features/rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch new file mode 100644 index 00000000..3c62cff6 --- /dev/null +++ b/features/rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch @@ -0,0 +1,61 @@ +From a5c8ce0345b9379be44f67042816beb0afda8176 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Mon, 9 Nov 2020 23:32:39 +0100 +Subject: [PATCH 004/191] genirq: Move prio assignment into the newly created + thread + +With enabled threaded interrupts the nouveau driver reported the +following: +| Chain exists of: +| &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem +| +| Possible unsafe locking scenario: +| +| CPU0 CPU1 +| ---- ---- +| lock(&cpuset_rwsem); +| lock(&device->mutex); +| lock(&cpuset_rwsem); +| lock(&mm->mmap_lock#2); + +The device->mutex is nvkm_device::mutex. + +Unblocking the lockchain at `cpuset_rwsem' is probably the easiest thing +to do. +Move the priority assignment to the start of the newly created thread. + +Fixes: 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()") +Reported-by: Mike Galbraith <efault@gmx.de> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +[bigeasy: Patch description] +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de +--- + kernel/irq/manage.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c +index dec3f73e8db9..ac2c57429750 100644 +--- a/kernel/irq/manage.c ++++ b/kernel/irq/manage.c +@@ -1225,6 +1225,8 @@ static int irq_thread(void *data) + irqreturn_t (*handler_fn)(struct irq_desc *desc, + struct irqaction *action); + ++ sched_set_fifo(current); ++ + if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD, + &action->thread_flags)) + handler_fn = irq_forced_thread_fn; +@@ -1390,8 +1392,6 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary) + if (IS_ERR(t)) + return PTR_ERR(t); + +- sched_set_fifo(t); +- + /* + * We keep the reference to the task struct even if + * the thread dies to avoid that the interrupt code +-- +2.19.1 + |