diff options
Diffstat (limited to 'debian/patches-rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch')
| -rw-r--r-- | debian/patches-rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/debian/patches-rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch b/debian/patches-rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch new file mode 100644 index 000000000..4e2c06796 --- /dev/null +++ b/debian/patches-rt/genirq-Move-prio-assignment-into-the-newly-created-t.patch @@ -0,0 +1,57 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 10 Nov 2020 12:38:48 +0100 +Subject: [PATCH] genirq: Move prio assignment into the newly created thread +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.15/older/patches-5.15.3-rt21.tar.xz + +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> +Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> +Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de +--- + kernel/irq/manage.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +--- a/kernel/irq/manage.c ++++ b/kernel/irq/manage.c +@@ -1259,6 +1259,8 @@ 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; +@@ -1424,8 +1426,6 @@ setup_irq_thread(struct irqaction *new, + 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 |