Re: [PATCH v2] pci: fix unavailable irq number 255 reported by BIOS

From: Bjorn Helgaas
Date: Mon Jan 25 2016 - 15:58:27 EST


[+cc Thomas]

On Mon, Jan 25, 2016 at 02:59:38PM +0800, Chen Fan wrote:
> In our environment, when enable Secure boot, we found an abnormal
> phenomenon as following call trace shows. after investigation, we
> found the firmware assigned an irq number 255 which means unknown
> or no connection in PCI local spec for i801_smbus, meanwhile the
> ACPI didn't configure the pci irq routing. and the 255 irq number
> was assigned for megasa msix without IRQF_SHARED. then in this case
> during i801_smbus probe, the i801_smbus driver would request irq with
> bad irq number 255. but the 255 irq number was assigned for memgasa
> with MSIX enable. which will cause request_irq fails as call trace
> shows, here we use ~0U as invalid IRQ to identify the 0xff IRQ specified
> by BIOS.
>
> See the call trace:

Maybe you missed my suggestion that the timestamps aren't useful;
here's my suggestion again in more detail:

Changelogs are written once, but read dozens or hundreds of time, so
stripping out irrelevant details shows consideration for the readers.

> [ 32.459195] ipmi device interface
> [ 32.612907] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
> [ 32.800459] ixgbe: Intel(R) 10 Gigabit PCI Express Network Driver - version 4.0.1-k-rh
> [ 32.818319] ixgbe: Copyright (c) 1999-2014 Intel Corporation.
> [ 32.844009] lpc_ich 0001:80:1f.0: I/O space for ACPI uninitialized

I think the lines above are completely irrelevant.

> [ 32.850093] i801_smbus 0000:00:1f.3: enabling device (0140 -> 0143)
> [ 32.851134] i801_smbus 0000:00:1f.3: can't derive routing for PCI INT C
> [ 32.851136] i801_smbus 0000:00:1f.3: PCI INT C: no GSI
> [ 32.851164] genirq: Flags mismatch irq 255. 00000080 (i801_smbus) vs. 00000000 (megasa

These are useful, but the timestamps ("[ 32.850093]") are not.

> [ 32.851168] CPU: 0 PID: 2487 Comm: kworker/0:1 Not tainted 3.10.0-229.el7.x86_64 #1
> [ 32.851170] Hardware name: FUJITSU PRIMEQUEST 2800E2/D3736, BIOS PRIMEQUEST 2000 Serie5

These are probably useful; it's nice to know what kernel and hardware
is involved.

> [ 32.851178] Workqueue: events work_for_cpu_fn
> [ 32.851208] ffff88086c330b00 00000000e233a9df ffff88086d57bca0 ffffffff81603f36
> [ 32.851227] ffff88086d57bcf8 ffffffff8110d23a ffff88686fe02000 0000000000000246
> [ 32.851246] ffff88086a9a8c00 00000000e233a9df ffffffffa00ad220 0000000000000080

I doubt these are useful.

> [ 32.851247] Call Trace:
> [ 32.851261] [<ffffffff81603f36>] dump_stack+0x19/0x1b
> [ 32.851271] [<ffffffff8110d23a>] __setup_irq+0x54a/0x570
> [ 32.851282] [<ffffffffa00ad220>] ? i801_check_pre.isra.5+0xe0/0xe0 [i2c_i801]
> [ 32.851289] [<ffffffff8110d3bc>] request_threaded_irq+0xcc/0x170
> [ 32.851298] [<ffffffffa00ae87f>] i801_probe+0x32f/0x508 [i2c_i801]
> [ 32.851308] [<ffffffff81308385>] local_pci_probe+0x45/0xa0

The above might be useful, but the addresses ("[<ffffffff81603f36>]")
are not, and you should go through them manually and strip out the
lines that are junk from the stack. For example, I don't think
request_threaded_irq() really calls i801_check_pre().

> [ 32.851315] [<ffffffff8108bfd4>] work_for_cpu_fn+0x14/0x20
> [ 32.851323] [<ffffffff8108f0ab>] process_one_work+0x17b/0x470
> [ 32.851330] [<ffffffff81090003>] worker_thread+0x293/0x400
> [ 32.851338] [<ffffffff8108fd70>] ? rescuer_thread+0x400/0x400
> [ 32.851346] [<ffffffff8109726f>] kthread+0xcf/0xe0
> [ 32.851353] [<ffffffff810971a0>] ? kthread_create_on_node+0x140/0x140
> [ 32.851362] [<ffffffff81613cfc>] ret_from_fork+0x7c/0xb0
> [ 32.851369] [<ffffffff810971a0>] ? kthread_create_on_node+0x140/0x140

The lines above are completely useless.

> [ 32.851373] i801_smbus 0000:00:1f.3: Failed to allocate irq 255: -16
> [ 32.851435] i801_smbus: probe of 0000:00:1f.3 failed with error -16

> [ 33.180145] ixgbe 0000:5a:00.0: Multiq[ 33.240538] ixgbe 0000:5a:00.0: (PCI Express:03:e0
> [ 33.280826] ixgbe 0000:5a:00.0: MAC: 3, PHY: 0, PBA No: 000000-000

These ixgbe entries are irrelevant.

> Signed-off-by: Chen Fan <chen.fan.fnst@xxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/irq_vectors.h | 2 ++
> drivers/acpi/pci_irq.c | 11 ++++++++++-
> include/linux/interrupt.h | 9 +++++++++
> 3 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
> index 6ca9fd6..b616d69 100644
> --- a/arch/x86/include/asm/irq_vectors.h
> +++ b/arch/x86/include/asm/irq_vectors.h
> @@ -146,4 +146,6 @@
> #define NR_IRQS NR_IRQS_LEGACY
> #endif
>
> +#define IRQ_INVALID (~0U)

If this is a good idea (I cc'd Thomas, the IRQ maintainer, for his
thoughts), I'd like to see this in a more generic place so it isn't
x86-specific.

> #endif /* _ASM_X86_IRQ_VECTORS_H */
> diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
> index d30184c..819eb23 100644
> --- a/drivers/acpi/pci_irq.c
> +++ b/drivers/acpi/pci_irq.c
> @@ -33,6 +33,7 @@
> #include <linux/pci.h>
> #include <linux/acpi.h>
> #include <linux/slab.h>
> +#include <linux/interrupt.h>
>
> #define PREFIX "ACPI: "
>
> @@ -436,7 +437,15 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
> * driver reported one, then use it. Exit in any case.
> */
> if (gsi < 0) {
> - if (acpi_isa_register_gsi(dev))
> +#ifdef CONFIG_X86
> + /*
> + * The Interrupt Line value of 0xff is defined to mean "unknown"
> + * or "no connection" (PCI 3.0, Section 6.2.4, footnote on page
> + * 223), using ~0U as invalid IRQ.
> + */
> + dev->irq = (dev->irq == 0xff) ? IRQ_INVALID : dev->irq;

It's much simpler and clearer to write:

if (dev->irq == 0xff)
dev->irq = IRQ_INVALID;

> +#endif
> + if (!irq_is_valid(dev->irq) || acpi_isa_register_gsi(dev))
> dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
> pin_name(pin));
>
> diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
> index cb30edb..2f0d46b 100644
> --- a/include/linux/interrupt.h
> +++ b/include/linux/interrupt.h
> @@ -198,6 +198,15 @@ extern void enable_percpu_irq(unsigned int irq, unsigned int type);
> extern bool irq_percpu_is_enabled(unsigned int irq);
> extern void irq_wake_thread(unsigned int irq, void *dev_id);
>
> +static inline bool irq_is_valid(unsigned int irq)
> +{
> +#ifdef CONFIG_X86
> + if (irq == IRQ_INVALID)
> + return false;
> +#endif
> + return true;
> +}

I don't like the x86 ifdef. I'd prefer:

static inline bool irq_valid(unsigned int irq)
{
if (irq < NR_IRQS)
return true;
return false;
}

This could be used in many of the places that currently use NR_IRQS.

My suggestion:

- patch 1: Add IRQ_INVALID and irq_valid() as generic things
- patch 2: Use irq_valid() in all the places where it can obviously
replace NR_IRQS
- patch 3: Add the acpi_pci_irq_enable() check. This is now a
trivial patch, basically just this:

+ #ifdef CONFIG_X86
+ if (dev->irq == 0xff)
+ dev->irq = IRQ_INVALID;
+ #endif
+ if (!irq_valid(dev->irq) ...

Bjorn