Re: [PATCH] x86: Don't allow nr_irqs > NR_IRQS

[Cyrill Gorcunov <gorcunov@gmail.com>]

[Ben Hutchings - Tue, Nov 04, 2008 at 05:18:22PM +0000]
| 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;
|  }
|

Hi Ben,

I don't think that is because of Thomas' commit. If we've got
number of pins larger then we expect it means something wrong
with our NR_IRQS. Is it possible to get your .config?
 
		- Cyrill -