Commit bbfe65c2 authored Oct 11, 2013 by Thomas Pfaff Committed by Thomas Gleixner Oct 28, 2013

genirq: Set the irq thread policy without checking CAP_SYS_NICE



In commit ee238713 ("genirq: Set irq thread to RT priority on
creation") we moved the assigment of the thread's priority from the
thread's function into __setup_irq(). That function may run in user
context for instance if the user opens an UART node and then driver
calls requests in the ->open() callback. That user may not have
CAP_SYS_NICE and so the irq thread won't run with the SCHED_OTHER
policy.

This patch uses sched_setscheduler_nocheck() so we omit the CAP_SYS_NICE
check which is otherwise required for the SCHED_OTHER policy.

[bigeasy: Rewrite the changelog]

Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
Cc: Ivo Sieben <meltedpianoman@gmail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1381489240-29626-1-git-send-email-bigeasy@linutronix.de


Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent fd2f3b7e

kernel/irq/manage.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -956,7 +956,7 @@ __setup_irq(unsigned int irq, struct irq_desc desc, struct irqaction new)
		goto out_mput;
		}

		sched_setscheduler(t, SCHED_FIFO, &param);
		sched_setscheduler_nocheck(t, SCHED_FIFO, &param);

		/*
		* We keep the reference to the task struct even if