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From: Ben Hutchings <bhutchings@solarflare.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] x86: Don't allow nr_irqs > NR_IRQS
Date: Tue, 04 Nov 2008 17:18:22 +0000	[thread overview]
Message-ID: <1225819102.3074.15.camel@achroite> (raw)

On some systems probe_nr_irqs() can return a value larger than
NR_IRQS.  This will lead to probe_irq_on() overrunning the irq_desc
array.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
 arch/x86/kernel/io_apic.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

I hit this when running net-next-2.6 (close to 2.6.28-rc3) on a
Supermicro dual Xeon system.  NR_IRQS is 224 but probe_nr_irqs() detects
5 IOAPICs (!) and returns 240.  Here are the log messages:

Tue Nov  4 16:53:47 2008 ACPI: IOAPIC (id[0x01] address[0xfec00000] gsi_base[0])
Tue Nov  4 16:53:47 2008 IOAPIC[0]: apic_id 1, version 32, address 0xfec00000, GSI 0-23
Tue Nov  4 16:53:47 2008 ACPI: IOAPIC (id[0x02] address[0xfec81000] gsi_base[24])
Tue Nov  4 16:53:47 2008 IOAPIC[1]: apic_id 2, version 32, address 0xfec81000, GSI 24-47
Tue Nov  4 16:53:47 2008 ACPI: IOAPIC (id[0x03] address[0xfec81400] gsi_base[48])
Tue Nov  4 16:53:47 2008 IOAPIC[2]: apic_id 3, version 32, address 0xfec81400, GSI 48-71
Tue Nov  4 16:53:47 2008 ACPI: IOAPIC (id[0x04] address[0xfec82000] gsi_base[72])
Tue Nov  4 16:53:47 2008 IOAPIC[3]: apic_id 4, version 32, address 0xfec82000, GSI 72-95
Tue Nov  4 16:53:47 2008 ACPI: IOAPIC (id[0x05] address[0xfec82400] gsi_base[96])
Tue Nov  4 16:53:47 2008 IOAPIC[4]: apic_id 5, version 32, address 0xfec82400, GSI 96-119
Tue Nov  4 16:53:47 2008 ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 high edge)
Tue Nov  4 16:53:47 2008 ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
Tue Nov  4 16:53:47 2008 Enabling APIC mode:  Flat.  Using 5 I/O APICs

I think this has become possible since:

commit d6c88a507ef0b6afdb013cba4e7804ba7324d99a
Author: Thomas Gleixner <tglx@linutronix.de>
Date:   Wed Oct 15 15:27:23 2008 +0200

    genirq: revert dynarray

    Revert the dynarray changes. They need more thought and polishing.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Ben.

diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index b764d74..c8482fb 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -3611,6 +3611,8 @@ int __init probe_nr_irqs(void)
 	/* something wrong ? */
 	if (nr < nr_min)
 		nr = nr_min;
+	if (nr > NR_IRQS)
+		nr = NR_IRQS;
 
 	return nr;
 }

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.


             reply	other threads:[~2008-11-04 17:18 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-04 17:18 Ben Hutchings [this message]
2008-11-04 18:00 ` Cyrill Gorcunov
2008-11-04 18:36   ` Ben Hutchings
2008-11-04 18:56     ` Yinghai Lu
2008-11-04 19:01     ` Cyrill Gorcunov
     [not found]       ` <1225825559.3074.26.camel@achroite>
     [not found]         ` <20081104194606.GJ21470@localhost>
2008-11-04 21:31           ` Ben Hutchings
2008-11-05 12:04 ` [PATCH v2] " Ben Hutchings
2008-11-05 19:11   ` Cyrill Gorcunov
2008-11-05 19:15     ` Ben Hutchings
2008-11-05 19:26       ` Cyrill Gorcunov
2008-11-06  9:03       ` Ingo Molnar
2008-11-06  6:24   ` Ingo Molnar

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