On Fri, Mar 02, 2018 at 04:44:13PM +0000, Mark Rutland wrote: > On Fri, Mar 02, 2018 at 02:52:07PM +0100, Grzegorz Jaszczyk wrote: > > 2018-03-02 14:15 GMT+01:00 Mark Rutland <mark.rutl...@arm.com>: > > > 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? > > > > > > 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.
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: [ 384.653153] Call trace: [ 384.655581] sysrq_handle_crash+0x20/0x30 [ 384.659559] __handle_sysrq+0xa8/0x1a0 [ 384.663278] handle_sysrq+0x28/0x38 [ 384.666738] pl011_fifo_to_tty+0x150/0x1a8 [ 384.670801] pl011_int+0x30c/0x430 [ 384.674177] __handle_irq_event_percpu+0x5c/0x148 [ 384.678843] handle_irq_event_percpu+0x34/0x88 [ 384.683250] handle_irq_event+0x48/0x78 [ 384.687056] handle_fasteoi_irq+0xa8/0x180 [ 384.691119] generic_handle_irq+0x24/0x38 [ 384.695095] __handle_domain_irq+0x5c/0xb0 [ 384.699158] gic_handle_irq+0x58/0xa8 [ 384.702790] el1_irq+0xb0/0x128 [ 384.705907] cpuidle_enter_state+0x138/0x220 [ 384.710142] cpuidle_enter+0x18/0x20 [ 384.713690] call_cpuidle+0x1c/0x38 [ 384.717151] do_idle+0x1b0/0x1e8 [ 384.720354] cpu_startup_entry+0x20/0x28 [ 384.724246] rest_init+0xd0/0xe0 [ 384.727450] start_kernel+0x3e4/0x410 On a separate note, the crashkernel complained: [ 0.224730] CPU: CPUs started in inconsistent modes ... which is a separate disaster. I suspect the kexec code failed to punt the crash CPU back to EL2 as it should have. Thanks, Mark.