netdev - [PATCH 13/45] timer: Use get/put_online_cpus

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 23 Jun 2013 19:10:56 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	tglx@...utronix.de, peterz@...radead.org, tj@...nel.org,
	oleg@...hat.com, paulmck@...ux.vnet.ibm.com, rusty@...tcorp.com.au,
	mingo@...nel.org, akpm@...ux-foundation.org, namhyung@...nel.org,
	walken@...gle.com, vincent.guittot@...aro.org, laijs@...fujitsu.com
Cc:	rostedt@...dmis.org, wangyun@...ux.vnet.ibm.com,
	xiaoguangrong@...ux.vnet.ibm.com, sbw@....edu, fweisbec@...il.com,
	zhong@...ux.vnet.ibm.com, nikunj@...ux.vnet.ibm.com,
	srivatsa.bhat@...ux.vnet.ibm.com, linux-pm@...r.kernel.org,
	linux-arch@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 13/45] timer: Use get/put_online_cpus_atomic() to prevent CPU
 offline

Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.

Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.

Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 kernel/timer.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/timer.c b/kernel/timer.c
index 15ffdb3..5db594c 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -729,6 +729,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
 	timer_stats_timer_set_start_info(timer);
 	BUG_ON(!timer->function);
 
+	get_online_cpus_atomic();
 	base = lock_timer_base(timer, &flags);
 
 	ret = detach_if_pending(timer, base, false);
@@ -768,6 +769,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
 
 out_unlock:
 	spin_unlock_irqrestore(&base->lock, flags);
+	put_online_cpus_atomic();
 
 	return ret;
 }
@@ -926,6 +928,7 @@ void add_timer_on(struct timer_list *timer, int cpu)
 
 	timer_stats_timer_set_start_info(timer);
 	BUG_ON(timer_pending(timer) || !timer->function);
+	get_online_cpus_atomic();
 	spin_lock_irqsave(&base->lock, flags);
 	timer_set_base(timer, base);
 	debug_activate(timer, timer->expires);
@@ -940,6 +943,7 @@ void add_timer_on(struct timer_list *timer, int cpu)
 	 */
 	wake_up_nohz_cpu(cpu);
 	spin_unlock_irqrestore(&base->lock, flags);
+	put_online_cpus_atomic();
 }
 EXPORT_SYMBOL_GPL(add_timer_on);
 

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html