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Groups > linux.kernel > #1668549
| From | Mike Galbraith <efault@gmx.de> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [ANNOUNCE] v4.11.5-rt1 |
| Date | 2017-06-18 08:50 +0200 |
| Message-ID | <tTCc1-1D2-1@gated-at.bofh.it> (permalink) |
| References | <tSX8R-7mb-7@gated-at.bofh.it> <tTh7A-4kg-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Sat, 2017-06-17 at 10:14 +0200, Mike Galbraith wrote:
>
>... the RT workaround in futex.c induces
> grumbling in nonrt builds with PREEMPT_COUNT enabled.
A trivial way to fix it up is to...
futex: Fix migrate_disable/enable workaround for !PREEMPT_RT_FULL
The imbalance fixed by aed0f50e58eb only exists for PREEMPT_RT_FULL,
and creates for other PREEMPT_COUNT configs. Create/use _rt variants
of migrate_disable/enable() which are compiled away when not needed.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Fixes: aed0f50e58eb ("futex: workaround migrate_disable/enable in different context")
---
include/linux/preempt.h | 11 +++++++++++
kernel/futex.c | 8 ++++----
2 files changed, 15 insertions(+), 4 deletions(-)
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -227,12 +227,21 @@ do { \
extern void migrate_disable(void);
extern void migrate_enable(void);
+#ifdef CONFIG_PREEMPT_RT_FULL
+#define migrate_disable_rt() migrate_disable()
+#define migrate_enable_rt() migrate_enable()
+#else
+static inline void migrate_disable_rt(void) { }
+static inline void migrate_enable_rt(void) { }
+#endif
int __migrate_disabled(struct task_struct *p);
#else
#define migrate_disable() barrier()
#define migrate_enable() barrier()
+static inline void migrate_disable_rt(void) { }
+static inline void migrate_enable_rt(void) { }
static inline int __migrate_disabled(struct task_struct *p)
{
return 0;
@@ -323,6 +332,8 @@ do { \
#define migrate_disable() barrier()
#define migrate_enable() barrier()
+static inline void migrate_disable_rt(void) { }
+static inline void migrate_enable_rt(void) { }
static inline int __migrate_disabled(struct task_struct *p)
{
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2690,12 +2690,12 @@ static int futex_lock_pi(u32 __user *uad
* one migrate_disable() pending in the slow-path which is reversed
* after the raw_spin_unlock_irq() where we leave the atomic context.
*/
- migrate_disable();
+ migrate_disable_rt();
spin_unlock(q.lock_ptr);
ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
- migrate_enable();
+ migrate_enable_rt();
if (ret) {
if (ret == 1)
@@ -2846,13 +2846,13 @@ static int futex_unlock_pi(u32 __user *u
* won't undo the migrate_disable() which was issued when
* locking hb->lock.
*/
- migrate_disable();
+ migrate_disable_rt();
spin_unlock(&hb->lock);
/* Drops pi_state->pi_mutex.wait_lock */
ret = wake_futex_pi(uaddr, uval, pi_state);
- migrate_enable();
+ migrate_enable_rt();
put_pi_state(pi_state);
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[ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-16 13:00 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-17 10:20 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-18 08:50 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 11:00 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 12:20 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 12:50 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 13:40 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 14:00 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 15:00 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 16:10 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 16:40 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 17:10 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 18:20 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 18:30 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 18:50 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Steven Rostedt <rostedt@goodmis.org> - 2017-06-19 16:10 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-06-19 16:20 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Steven Rostedt <rostedt@goodmis.org> - 2017-06-19 16:50 +0200
Re: [ANNOUNCE] v4.11.5-rt1 Mike Galbraith <efault@gmx.de> - 2017-06-19 18:40 +0200
[patch-rt] rtmutex: Fix lock stealing logic Mike Galbraith <efault@gmx.de> - 2017-06-18 19:10 +0200
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