2018-03-02 17:57 GMT+01:00 Mark Rutland [off-list ref]:

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Do you see this for a panic() in *any* interrupt handler?

I only test with this two interrupt handlers: watchdog and i2c but I
think it will behave the same with others - I can try with other if
you want, any suggestion which? Maybe with some PPI interrupt instead?

I was able to reproduce it from other interrupts handler (UART, I2C,
timer and watchdog) no difference if it is PPI or SPI interrupt. I
also reproduce this issue with GICv3. But again it only happens when
eoimode = 0.

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Can you trigger the issue with magic-sysrq c, for example?

There is no problem when I trigger it via 'echo c >
/proc/sysrq-trigger' - it works well all the time. The problem appears
only, when the kexec/kdump procedure is triggered from interrupt
context

I'd meant that you'd send sysrq + c over serial, rather than writing to
/proc/sysrq-trigger. That way, the panic will be in the context of the
UART IRQ handler.

If that shows the issue, that's ilikely to be the easiest way for
someone else to reproduce and investigate this.

Yes it can be triggered by sending sysrq + c and indeed it is the
easiest way to reproduce it.

FWIW, having just given this a go on my Juno R1 with v4.16-rc3
defconfig, the UART IRQs work fine in the crash kernel. That crash
happened in IRQ context:

I think that by default Juno uses eoimode = 1, did you try it when
eoimode was forced to be 0? Only eoimode = 0 triggers the issue.

Thank you,
Grzegorz