linux-kernel - [RFC PATCH 05/10] kick_process(), cpu-hotplug: Prevent offlining of target CPU properly

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]

Message-ID: <20121204085504.25919.38913.stgit@srivatsabhat.in.ibm.com>
Date:	Tue, 04 Dec 2012 14:25:06 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	tglx@...utronix.de, peterz@...radead.org,
	paulmck@...ux.vnet.ibm.com, rusty@...tcorp.com.au,
	mingo@...nel.org, akpm@...ux-foundation.org, namhyung@...nel.org,
	vincent.guittot@...aro.org
Cc:	sbw@....edu, tj@...nel.org, amit.kucheria@...aro.org,
	rostedt@...dmis.org, rjw@...k.pl, srivatsa.bhat@...ux.vnet.ibm.com,
	wangyun@...ux.vnet.ibm.com, xiaoguangrong@...ux.vnet.ibm.com,
	nikunj@...ux.vnet.ibm.com, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH 05/10] kick_process(),
 cpu-hotplug: Prevent offlining of target CPU properly

With stop_machine() gone from the CPU offline path, we can't depend on
preempt_disable() to prevent CPUs from going offline from under us.

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

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 kernel/sched/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ef6ada4..c1a5d93 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1091,11 +1091,11 @@ void kick_process(struct task_struct *p)
 {
 	int cpu;
 
-	preempt_disable();
+	get_online_cpus_stable_atomic();
 	cpu = task_cpu(p);
 	if ((cpu != smp_processor_id()) && task_curr(p))
 		smp_send_reschedule(cpu);
-	preempt_enable();
+	put_online_cpus_stable_atomic();
 }
 EXPORT_SYMBOL_GPL(kick_process);
 #endif /* CONFIG_SMP */

--
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/