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Message-ID: <50D1E1D1.4040803@openvz.org>
Date: Wed, 19 Dec 2012 19:48:33 +0400
From: Konstantin Khlebnikov <khlebnikov@...nvz.org>
To: linux-kernel@...r.kernel.org
CC: Wim Van Sebroeck <wim@...ana.be>, linux-watchdog@...r.kernel.org,
Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: [PATCH] drivers/watchdog/eurotechwdt: handle spurious interrupts
on wrong hardware
Konstantin Khlebnikov wrote:
> "eurotechwdt" hasn't any PCI-ID or DMI checks, thus is can be loaded on any
> hardware. On my PC this leads to immediate reboot, because driver got irq right
> after registering irq handler. This patch rejects interrupts until device
> activation. There is no sense to load this driver without special hardware,
> but such bugs blocks mine automatic testing for allmodconfig kernels.
Ah, this hack does not fixes the problem. Please ignore this patch.
I'll blacklist this module instead, because I have no idea how to fix this properly.
>
> Signed-off-by: Konstantin Khlebnikov<khlebnikov@...nvz.org>
> Cc: Wim Van Sebroeck<wim@...ana.be>
> Cc: linux-watchdog@...r.kernel.org
> Cc: Alan Cox<alan@...rguk.ukuu.org.uk>
>
> ---
>
> by default driver uses 10th irq, on my machine it's free:
>
> root@...z:~# cat /proc/interrupts
> CPU0 CPU1
> 0: 187 0 IO-APIC-edge timer
> 1: 0 8 IO-APIC-edge i8042
> 7: 2 0 IO-APIC-edge parport0
> 8: 0 1 IO-APIC-edge rtc0
> 9: 0 0 IO-APIC-fasteoi acpi
> 10: 1 0 IO-APIC-edge
> 14: 1 61 IO-APIC-edge pata_amd
> 15: 0 0 IO-APIC-edge pata_amd
> 20: 0 317 IO-APIC-fasteoi snd_hda_intel
> 22: 0 2 IO-APIC-fasteoi ehci_hcd:usb1, sata_nv
> 23: 6 3667 IO-APIC-fasteoi ohci_hcd:usb2, sata_nv
> 41: 93 776888 PCI-MSI-edge eth0
> NMI: 0 2 Non-maskable interrupts
> LOC: 13293 32610 Local timer interrupts
> SPU: 0 0 Spurious interrupts
> PMI: 0 2 Performance monitoring interrupts
> IWI: 0 0 IRQ work interrupts
> RTR: 0 0 APIC ICR read retries
> RES: 11427 7619 Rescheduling interrupts
> CAL: 182 52 Function call interrupts
> TLB: 824 580 TLB shootdowns
> TRM: 0 0 Thermal event interrupts
> THR: 0 0 Threshold APIC interrupts
> MCE: 0 0 Machine check exceptions
> MCP: 2 2 Machine check polls
> ERR: 1
> MIS: 0
> ---
> drivers/watchdog/eurotechwdt.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/watchdog/eurotechwdt.c b/drivers/watchdog/eurotechwdt.c
> index cd31b8a..7d24914 100644
> --- a/drivers/watchdog/eurotechwdt.c
> +++ b/drivers/watchdog/eurotechwdt.c
> @@ -65,6 +65,7 @@
> static unsigned long eurwdt_is_open;
> static int eurwdt_timeout;
> static char eur_expect_close;
> +static bool eurwdt_is_active;
> static DEFINE_SPINLOCK(eurwdt_lock);
>
> /*
> @@ -139,6 +140,7 @@ static inline void eurwdt_disable_timer(void)
> static void eurwdt_activate_timer(void)
> {
> eurwdt_disable_timer();
> + eurwdt_is_active = true;
> eurwdt_write_reg(WDT_CTRL_REG, 0x01); /* activate the WDT */
> eurwdt_write_reg(WDT_OUTPIN_CFG,
> !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
> @@ -164,6 +166,11 @@ static void eurwdt_activate_timer(void)
>
> static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
> {
> + if (!eurwdt_is_active) {
> + pr_crit("spurious interrupt\n");
> + return IRQ_NONE;
> + }
> +
> pr_crit("timeout WDT timeout\n");
>
> #ifdef ONLY_TESTING
>
--
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