| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 13 Mar 2009 14:57:28 GMT
From: Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
a.p.zijlstra@...llo.nl, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:core/locking] hrtimer: fix rq->lock inversion (again)
Commit-ID: 84648567ee357abd8879257018f38f8b6b35334d
Gitweb: http://git.kernel.org/tip/84648567ee357abd8879257018f38f8b6b35334d
Author: Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Fri, 13 Mar 2009 12:21:27 +0100
Commit: Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 13 Mar 2009 15:31:28 +0100
hrtimer: fix rq->lock inversion (again)
It appears I inadvertly introduced rq->lock recursion to the
hrtimer_start() path when I delegated running already expired
timers to softirq context.
This patch fixes it by introducing a __hrtimer_start_range_ns()
method that will not use raise_softirq_irqoff() but
__raise_softirq_irqoff() which avoids the wakeup.
It then also changes schedule() to check for pending softirqs and
do the wakeup then, I'm not quite sure I like this last bit, nor
am I convinced its really needed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: paulus@...ba.org
LKML-Reference: <20090313112301.096138802@...llo.nl>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
include/linux/hrtimer.h | 5 ++++
include/linux/interrupt.h | 1 +
kernel/hrtimer.c | 55 +++++++++++++++++++++++++++-----------------
kernel/sched.c | 14 +++++++++--
kernel/softirq.c | 2 +-
5 files changed, 52 insertions(+), 25 deletions(-)
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index bd37078..0d2f7c8 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -336,6 +336,11 @@ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
const enum hrtimer_mode mode);
extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
unsigned long range_ns, const enum hrtimer_mode mode);
+extern int
+__hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+ unsigned long delta_ns,
+ const enum hrtimer_mode mode, int wakeup);
+
extern int hrtimer_cancel(struct hrtimer *timer);
extern int hrtimer_try_to_cancel(struct hrtimer *timer);
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 169db98..663b8bc 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -274,6 +274,7 @@ extern void softirq_init(void);
#define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0)
extern void raise_softirq_irqoff(unsigned int nr);
extern void raise_softirq(unsigned int nr);
+extern void wakeup_softirqd(void);
/* This is the worklist that queues up per-cpu softirq work.
*
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index f394d2a..cb8a15c 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -651,14 +651,20 @@ static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
* and expiry check is done in the hrtimer_interrupt or in the softirq.
*/
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
- struct hrtimer_clock_base *base)
+ struct hrtimer_clock_base *base,
+ int wakeup)
{
if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
- spin_unlock(&base->cpu_base->lock);
- raise_softirq_irqoff(HRTIMER_SOFTIRQ);
- spin_lock(&base->cpu_base->lock);
+ if (wakeup) {
+ spin_unlock(&base->cpu_base->lock);
+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ spin_lock(&base->cpu_base->lock);
+ } else
+ __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+
return 1;
}
+
return 0;
}
@@ -703,7 +709,8 @@ static inline int hrtimer_is_hres_enabled(void) { return 0; }
static inline int hrtimer_switch_to_hres(void) { return 0; }
static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base) { }
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
- struct hrtimer_clock_base *base)
+ struct hrtimer_clock_base *base,
+ int wakeup)
{
return 0;
}
@@ -886,20 +893,9 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
return 0;
}
-/**
- * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
- * @timer: the timer to be added
- * @tim: expiry time
- * @delta_ns: "slack" range for the timer
- * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
- *
- * Returns:
- * 0 on success
- * 1 when the timer was active
- */
-int
-hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_ns,
- const enum hrtimer_mode mode)
+int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+ unsigned long delta_ns, const enum hrtimer_mode mode,
+ int wakeup)
{
struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
@@ -940,12 +936,29 @@ hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_n
* XXX send_remote_softirq() ?
*/
if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
- hrtimer_enqueue_reprogram(timer, new_base);
+ hrtimer_enqueue_reprogram(timer, new_base, wakeup);
unlock_hrtimer_base(timer, &flags);
return ret;
}
+
+/**
+ * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
+ * @timer: the timer to be added
+ * @tim: expiry time
+ * @delta_ns: "slack" range for the timer
+ * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
+ *
+ * Returns:
+ * 0 on success
+ * 1 when the timer was active
+ */
+int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+ unsigned long delta_ns, const enum hrtimer_mode mode)
+{
+ return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
+}
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
/**
@@ -961,7 +974,7 @@ EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
- return hrtimer_start_range_ns(timer, tim, 0, mode);
+ return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
}
EXPORT_SYMBOL_GPL(hrtimer_start);
diff --git a/kernel/sched.c b/kernel/sched.c
index 01275cb..1f43d81 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -231,13 +231,20 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
spin_lock(&rt_b->rt_runtime_lock);
for (;;) {
+ unsigned long delta;
+ ktime_t soft, hard;
+
if (hrtimer_active(&rt_b->rt_period_timer))
break;
now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
- hrtimer_start_expires(&rt_b->rt_period_timer,
- HRTIMER_MODE_ABS);
+
+ soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
+ hard = hrtimer_get_expires(&rt_b->rt_period_timer);
+ delta = ktime_to_ns(ktime_sub(hard, soft));
+ __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
+ HRTIMER_MODE_ABS, 0);
}
spin_unlock(&rt_b->rt_runtime_lock);
}
@@ -1129,7 +1136,8 @@ static __init void init_hrtick(void)
*/
static void hrtick_start(struct rq *rq, u64 delay)
{
- hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
+ __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
+ HRTIMER_MODE_REL, 0);
}
static inline void init_hrtick(void)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index f813122..34c309d 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -58,7 +58,7 @@ static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
* to the pending events, so lets the scheduler to balance
* the softirq load for us.
*/
-static inline void wakeup_softirqd(void)
+void wakeup_softirqd(void)
{
/* Interrupts are disabled: no need to stop preemption */
struct task_struct *tsk = __get_cpu_var(ksoftirqd);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists