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>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Julia Cartwright <julia@ni.com>,
Daniel Wagner <daniel.wagner@siemens.com>,
tom.zanussi@linux.intel.com
Subject: [PATCH RT 11/13] x86/mm/pat: disable preemption __split_large_page() after spin_lock()
Date: Mon, 07 Jan 2019 14:53:03 -0500 [thread overview]
Message-ID: <20190107195333.842328119@goodmis.org> (raw)
In-Reply-To: 20190107195252.599921907@goodmis.org
4.14.87-rt50-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ Upstream commit 45c6ff4811878e5c1c2ae31303cd95cdc6ae2ab4 ]
Commit "x86/mm/pat: Disable preemption around __flush_tlb_all()" added a
warning if __flush_tlb_all() is invoked in preemptible context. On !RT
the warning does not trigger because a spin lock is acquired which
disables preemption. On RT the spin lock does not disable preemption and
so the warning is seen.
Disable preemption to avoid the warning __flush_tlb_all().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
arch/x86/mm/pageattr.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 835620ab435f..57a04ef6fe47 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -661,12 +661,18 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
pgprot_t ref_prot;
spin_lock(&pgd_lock);
+ /*
+ * Keep preemption disabled after __flush_tlb_all() which expects not be
+ * preempted during the flush of the local TLB.
+ */
+ preempt_disable();
/*
* Check for races, another CPU might have split this page
* up for us already:
*/
tmp = _lookup_address_cpa(cpa, address, &level);
if (tmp != kpte) {
+ preempt_enable();
spin_unlock(&pgd_lock);
return 1;
}
@@ -696,6 +702,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
break;
default:
+ preempt_enable();
spin_unlock(&pgd_lock);
return 1;
}
@@ -743,6 +750,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
* going on.
*/
__flush_tlb_all();
+ preempt_enable();
spin_unlock(&pgd_lock);
return 0;
--
2.19.2
next prev parent reply other threads:[~2019-01-07 19:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 19:52 [PATCH RT 00/13] Linux 4.14.87-rt50-rc1 Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 01/13] work-simple: drop a shit statement in SWORK_EVENT_PENDING Steven Rostedt
2019-01-08 3:06 ` Sergey Senozhatsky
2019-01-08 3:26 ` Steven Rostedt
2019-01-08 4:47 ` Sergey Senozhatsky
2019-01-08 9:00 ` Sebastian Andrzej Siewior
2019-01-07 19:52 ` [PATCH RT 02/13] kthread: convert worker lock to raw spinlock Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 03/13] mm/kasan: make quarantine_lock a raw_spinlock_t Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 05/13] sched/migrate_disable: Add export_symbol_gpl for __migrate_disabled Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 06/13] pinctrl: bcm2835: Use raw spinlock for RT compatibility Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 07/13] rcu: make RCU_BOOST default on RT without EXPERT Steven Rostedt
2019-01-07 19:53 ` [PATCH RT 08/13] x86/fpu: Disable preemption around local_bh_disable() Steven Rostedt
2019-01-07 19:53 ` [PATCH RT 09/13] hrtimer: move state change before hrtimer_cancel in do_nanosleep() Steven Rostedt
2019-01-07 19:53 ` [PATCH RT 10/13] drm/i915: disable tracing on -RT Steven Rostedt
2019-01-07 20:10 ` Sebastian Andrzej Siewior
2019-01-07 19:53 ` Steven Rostedt [this message]
2019-01-07 19:53 ` [PATCH RT 13/13] Linux 4.14.87-rt50-rc1 Steven Rostedt
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