On Fri, Dec 13, 2024 at 11:42:59AM +0100, Thomas Gleixner wrote:
> On Fri, Dec 13 2024 at 09:43, David Woodhouse wrote:
> > On Fri, 2024-12-13 at 09:31 +0000, David Woodhouse wrote:
> >>
> >> (gdb) p sysrq_handle_showstate('t')
> >>
> >> That didn't work. Maybe if I'd actually had no_console_suspend on this
> >> boot. Will try again.
> >
> > With your fix I get the same thing (both CPUs in idle thread). And with
> > no_console_suspend on the command line, 'p sysrq_handle_showstate('t')'
> > does work...
> >
> > [ 113.462898] task:loadret state:D stack:0 pid:707 tgid:707 ppid:531 flags:0x00004002
> > [ 113.463615] Call Trace:
> > [ 113.463841] <TASK>
> > [ 113.464029] __schedule+0x502/0x1a10
> > [ 113.464961] schedule+0x3a/0x140
> > [ 113.465234] schedule_timeout+0xcc/0x110
> > [ 113.465580] __wait_for_common+0x91/0x1c0
> > [ 113.466304] cpuhp_kick_ap_work+0x13e/0x390
> > [ 113.466657] _cpu_down+0xd4/0x370
> > [ 113.466936] freeze_secondary_cpus.cold+0x3f/0xd4
> > [ 113.467326] kernel_kexec+0xa2/0x1a0
>
> That's the control thread on CPU0. The hotplug thread on CPU1 is stuck
> here:
>
> task:cpuhp/1 state:D stack:0 pid:24 tgid:24 ppid:2 flags:0x00004000
> Call Trace:
> <TASK>
> __schedule+0x51f/0x1a80
> schedule+0x3a/0x140
> schedule_timeout+0x90/0x110
> msleep+0x2b/0x40
> blk_mq_hctx_notify_offline+0x160/0x3a0
> cpuhp_invoke_callback+0x2a8/0x6c0
> cpuhp_thread_fun+0x1ed/0x270
> smpboot_thread_fn+0xda/0x1d0
>
> So something with those blk_mq fixes went sideways.
The cpuhp callback is just waiting for inflight IOs to be completed when
the irq is still live.
It looks same with the following report:
https://lore.kernel.org/linux-scsi/F991D40F7D096653+20241203211857.0291ab1b@john-PC/
Still triggered in case of kexec & qemu, which should be one qemu
problem.
Thanks,
Ming
