linux-kernel - [PATCH RESEND] x86/fixup_irq: Clean the offlining CPU from the irq affinity mask

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: <1348703122.19514.17.camel@cliu38-desktop-build>
Date:	Thu, 27 Sep 2012 07:45:22 +0800
From:	Chuansheng Liu <chuansheng.liu@...el.com>
To:	srivatsa.bhat@...ux.vnet.ibm.com, tglx@...utronix.de,
	mingo@...hat.com, x86@...nel.org
Cc:	linux-kernel@...r.kernel.org, yanmin_zhang@...ux.intel.com,
	chuansheng.liu@...el.com
Subject: [PATCH RESEND] x86/fixup_irq: Clean the offlining CPU from the irq
 affinity mask


When one CPU is going offline, and fixup_irqs() will re-set the
irq affinity in some cases, we should clean the offlining CPU from
the irq affinity.

The reason is setting offlining CPU as of the affinity is useless.
Moreover, the smp_affinity value will be confusing when the
offlining CPU come back again.

Example:
For irq 93 with 4 CPUS, the default affinity f(1111),
normal cases: 4 CPUS will receive the irq93 interrupts.

When echo 0 > /sys/devices/system/cpu/cpu3/online, just CPU0,1,2 will
receive the interrupts.

But after the CPU3 is online again, we will not set affinity,the result
will be:
the smp_affinity is f, but still just CPU0,1,2 can receive the interrupts.

So we should clean the offlining CPU from irq affinity mask
in fixup_irqs().

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
Signed-off-by: liu chuansheng <chuansheng.liu@...el.com>
---
 arch/x86/kernel/irq.c |   21 +++++++++++++++++----
 1 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index d44f782..ead0807 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -239,10 +239,13 @@ void fixup_irqs(void)
 	struct irq_desc *desc;
 	struct irq_data *data;
 	struct irq_chip *chip;
+	int cpu = smp_processor_id();
 
 	for_each_irq_desc(irq, desc) {
 		int break_affinity = 0;
 		int set_affinity = 1;
+		bool set_ret = false;
+
 		const struct cpumask *affinity;
 
 		if (!desc)
@@ -256,7 +259,8 @@ void fixup_irqs(void)
 		data = irq_desc_get_irq_data(desc);
 		affinity = data->affinity;
 		if (!irq_has_action(irq) || irqd_is_per_cpu(data) ||
-		    cpumask_subset(affinity, cpu_online_mask)) {
+		    cpumask_subset(affinity, cpu_online_mask) ||
+		    !cpumask_test_cpu(cpu, data->affinity)) {
 			raw_spin_unlock(&desc->lock);
 			continue;
 		}
@@ -277,9 +281,18 @@ void fixup_irqs(void)
 		if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
 			chip->irq_mask(data);
 
-		if (chip->irq_set_affinity)
-			chip->irq_set_affinity(data, affinity, true);
-		else if (!(warned++))
+		if (chip->irq_set_affinity) {
+			struct cpumask mask;
+			cpumask_copy(&mask, affinity);
+			cpumask_clear_cpu(cpu, &mask);
+			switch (chip->irq_set_affinity(data, &mask, true)) {
+			case IRQ_SET_MASK_OK:
+				cpumask_copy(data->affinity, &mask);
+			case IRQ_SET_MASK_OK_NOCOPY:
+				set_ret = true;
+			}
+		}
+		if ((!set_ret) && !(warned++))
 			set_affinity = 0;
 
 		/*
-- 
1.7.0.4



--
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/