linux-kernel - [PATCH 3/3] x86: Correct behaviour of irq affinity

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: <49C94DDF.2010703@kernel.org>
Date:	Tue, 24 Mar 2009 14:17:19 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Ingo Molnar <mingo@...e.hu>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Rusty Russell <rusty@...tcorp.com.au>
CC:	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 3/3] x86: Correct behaviour of irq affinity

From: Rusty Russell <rusty@...tcorp.com.au>

Impact: get correct smp_affinity as user requested

The effect of setting desc->affinity (ie. from userspace via sysfs) has varied
over time.  In 2.6.27, the 32-bit code anded the value with cpu_online_map,
and both 32 and 64-bit did that anding whenever a cpu was unplugged.

2.6.29 consolidated this into one routine (and fixed hotplug) but introduced
another variation: anding the affinity with cfg->domain.  Is this right, or
should we just set it to what the user said?  Or as now, indicate that we're
restricting it.

If we should change it, here's what the patch looks like against x86 tip
(cpu_mask_to_apicid_and already takes cpu_online_mask into account)

Signed-off-by: Yinghai Lu <yinghai@...nel.org>
Acked-by: "Eric W. Biederman" <ebiederm@...ssion.com>

---
 arch/x86/kernel/apic/io_apic.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-2.6/arch/x86/kernel/apic/io_apic.c
@@ -594,9 +594,10 @@ set_desc_affinity(struct irq_desc *desc,
 
 	/* check that before desc->addinity get updated */
 	set_extra_move_desc(desc, mask);
-	cpumask_and(desc->affinity, cfg->domain, mask);
 
-	return apic->cpu_mask_to_apicid_and(desc->affinity, cpu_online_mask);
+	cpumask_copy(desc->affinity, mask);
+
+	return apic->cpu_mask_to_apicid_and(desc->affinity, cfg->cpu_domain);
 }
 
 static void
--
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/