From 83a06bf50bdf2074b9404951ff60e142d159d93b Mon Sep 17 00:00:00 2001
From: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Date: Wed, 2 Feb 2011 16:04:02 -0200
Subject: [PATCH 1/2] RTC: Prevents a division by zero in kernel code.
This patch prevents a user space program from calling the RTC_IRQP_SET
ioctl with a negative value of frequency. Also, if this call is make
with a zero value of frequency, there would be a division by zero in the
kernel code.
[jstultz: Also initialize irq_freq to 1 to catch other divbyzero issues]
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/rtc/class.c | 1 +
drivers/rtc/interface.c | 3 +++
2 files changed, 4 insertions(+)
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 9583cbcc6b79..c404b61386bf 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -143,6 +143,7 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev,
rtc->id = id;
rtc->ops = ops;
rtc->owner = owner;
+ rtc->irq_freq = 1;
rtc->max_user_freq = 64;
rtc->dev.parent = dev;
rtc->dev.class = rtc_class;
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 925006d33109..a0c01967244d 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -464,6 +464,9 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
int err = 0;
unsigned long flags;
+ if (freq <= 0)
+ return -EINVAL;
+
spin_lock_irqsave(&rtc->irq_task_lock, flags);
if (rtc->irq_task != NULL && task == NULL)
err = -EBUSY;
From f266a5110d453b7987194460ac7edd31f1a5426c Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Thu, 3 Feb 2011 15:09:41 +0100
Subject: [PATCH 2/2] lockdep, timer: Fix del_timer_sync() annotation
Calling local_bh_enable() will want to actually start processing
softirqs, which isn't a good idea since this can get called with IRQs
disabled.
Cure this by using _local_bh_enable() which doesn't start processing
softirqs, and use raw_local_irq_save() to avoid any softirqs from
happening without letting lockdep think IRQs are in fact disabled.
Reported-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
LKML-Reference: <20110203141548.039540914@chello.nl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/timer.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/timer.c b/kernel/timer.c
index 43ca9936f2d0..d53ce66daea0 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -969,10 +969,14 @@ EXPORT_SYMBOL(try_to_del_timer_sync);
int del_timer_sync(struct timer_list *timer)
{
#ifdef CONFIG_LOCKDEP
+ unsigned long flags;
+
+ raw_local_irq_save(flags);
local_bh_disable();
lock_map_acquire(&timer->lockdep_map);
lock_map_release(&timer->lockdep_map);
- local_bh_enable();
+ _local_bh_enable();
+ raw_local_irq_restore(flags);
#endif
/*
* don't use it in hardirq context, because it