From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>, Julia Cartwright <julia@ni.com>,
Daniel Wagner <wagi@monom.org>, Tom Zanussi <zanussi@kernel.org>,
Julien Grall <julien.grall@arm.com>
Subject: [PATCH RT 10/30] hrtimer: Prevent using hrtimer_grab_expiry_lock() on migration_base
Date: Thu, 23 Jan 2020 15:39:40 -0500 [thread overview]
Message-ID: <20200123203943.749508731@goodmis.org> (raw)
In-Reply-To: 20200123203930.646725253@goodmis.org
4.19.94-rt39-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Julien Grall <julien.grall@arm.com>
[ Upstream commit cef1b87f98823af923a386f3f69149acb212d4a1 ]
As tglx puts it:
|If base == migration_base then there is no point to lock soft_expiry_lock
|simply because the timer is not executing the callback in soft irq context
|and the whole lock/unlock dance can be avoided.
Furthermore, all the path leading to hrtimer_grab_expiry_lock() assumes
timer->base and timer->base->cpu_base are always non-NULL. So it is safe
to remove the NULL checks here.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908211557420.2223@nanos.tec.linutronix.de
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bigeasy: rewrite changelog]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/time/hrtimer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 49d20fe8570f..1a5167c68310 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -943,7 +943,7 @@ void hrtimer_grab_expiry_lock(const struct hrtimer *timer)
{
struct hrtimer_clock_base *base = READ_ONCE(timer->base);
- if (timer->is_soft && base && base->cpu_base) {
+ if (timer->is_soft && base != &migration_base) {
spin_lock(&base->cpu_base->softirq_expiry_lock);
spin_unlock(&base->cpu_base->softirq_expiry_lock);
}
--
2.24.1
next prev parent reply other threads:[~2020-01-23 20:41 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 20:39 [PATCH RT 00/30] Linux 4.19.94-rt39-rc2 Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 01/30] i2c: exynos5: Remove IRQF_ONESHOT Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 02/30] i2c: hix5hd2: " Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 03/30] sched/deadline: Ensure inactive_timer runs in hardirq context Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 04/30] thermal/x86_pkg_temp: make pkg_temp_lock a raw spinlock Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 05/30] dma-buf: Use seqlock_t instread disabling preemption Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 06/30] KVM: arm/arm64: Let the timer expire in hardirq context on RT Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 07/30] x86: preempt: Check preemption level before looking at lazy-preempt Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 08/30] hrtimer: Use READ_ONCE to access timer->base in hrimer_grab_expiry_lock() Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 09/30] hrtimer: Dont grab the expiry lock for non-soft hrtimer Steven Rostedt
2020-01-23 20:39 ` Steven Rostedt [this message]
2020-04-27 13:10 ` [PATCH RT 10/30] hrtimer: Prevent using hrtimer_grab_expiry_lock() on migration_base Rasmus Villemoes
2020-04-27 19:06 ` Steven Rostedt
2020-04-27 19:26 ` Tom Zanussi
2020-04-28 6:51 ` Rasmus Villemoes
2020-04-28 7:03 ` Rasmus Villemoes
2020-04-28 12:59 ` Tom Zanussi
2020-04-28 13:07 ` Rasmus Villemoes
2020-04-28 13:43 ` Tom Zanussi
2020-01-23 20:39 ` [PATCH RT 11/30] hrtimer: Add a missing bracket and hide `migration_base on !SMP Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 12/30] posix-timers: Unlock expiry lock in the early return Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 14/30] sched: __set_cpus_allowed_ptr: Check cpus_mask, not cpus_ptr Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 15/30] sched: Remove dead __migrate_disabled() check Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 16/30] sched: migrate disable: Protect cpus_ptr with lock Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 17/30] lib/smp_processor_id: Dont use cpumask_equal() Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 18/30] futex: Make the futex_hash_bucket spinlock_t again and bring back its old state Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 19/30] locking/rtmutex: Clean ->pi_blocked_on in the error case Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 20/30] lib/ubsan: Dont seralize UBSAN report Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 21/30] kmemleak: Change the lock of kmemleak_object to raw_spinlock_t Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 22/30] sched: migrate_enable: Use select_fallback_rq() Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 23/30] sched: Lazy migrate_disable processing Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 24/30] sched: migrate_enable: Use stop_one_cpu_nowait() Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 25/30] Revert "ARM: Initialize split page table locks for vector page" Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 26/30] locking: Make spinlock_t and rwlock_t a RCU section on RT Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 27/30] sched/core: migrate_enable() must access takedown_cpu_task on !HOTPLUG_CPU Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 28/30] lib/smp_processor_id: Adjust check_preemption_disabled() Steven Rostedt
2020-01-23 20:39 ` [PATCH RT 29/30] sched: migrate_enable: Busy loop until the migration request is completed Steven Rostedt
2020-01-23 20:40 ` [PATCH RT 30/30] Linux 4.19.94-rt39-rc2 Steven Rostedt
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