2013-10-11 11:00:44

by Sebastian Andrzej Siewior

Subject: [PATCH] genirq: Set the irq thread policy without checking CAP_SYS_NICE

From: Thomas Pfaff <[email protected]>

In commit ee23871389 ("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.

Cc: Ivo Sieben <[email protected]>
Cc: [email protected]
Signed-off-by: Thomas Pfaff <[email protected]>
[bigeasy: rewrite the changelog]
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
---
kernel/irq/manage.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 514bcfd..3e59f95 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -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
--
1.8.4.rc3

2013-10-14 10:49:12

by Ivo Sieben

Subject: Re: [PATCH] genirq: Set the irq thread policy without checking CAP_SYS_NICE

Patch looks OK to me.. but I'm not an expert.

Regards,
Ivo Sieben

2013/10/11 Sebastian Andrzej Siewior <[email protected]>:
> From: Thomas Pfaff <[email protected]>
>
> In commit ee23871389 ("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.
>
> Cc: Ivo Sieben <[email protected]>
> Cc: [email protected]
> Signed-off-by: Thomas Pfaff <[email protected]>
> [bigeasy: rewrite the changelog]
> Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
> ---
> kernel/irq/manage.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 514bcfd..3e59f95 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -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
> --
> 1.8.4.rc3
>

2013-10-28 08:56:20

by tip-bot for Vasyl Gomonovych

Subject: [tip:irq/urgent] genirq: Set the irq thread policy without checking CAP_SYS_NICE

Commit-ID: bbfe65c219c638e19f1da5adab1005b2d68ca810
Gitweb: http://git.kernel.org/tip/bbfe65c219c638e19f1da5adab1005b2d68ca810
Author: Thomas Pfaff <[email protected]>
AuthorDate: Fri, 11 Oct 2013 13:00:40 +0200
Committer: Thomas Gleixner <[email protected]>
CommitDate: Mon, 28 Oct 2013 09:50:42 +0100

genirq: Set the irq thread policy without checking CAP_SYS_NICE

In commit ee23871389 ("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 <[email protected]>
Cc: Ivo Sieben <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
---
kernel/irq/manage.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 514bcfd..3e59f95 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -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