Add kexec list to CC. On 02/14/23 at 10:49am, Peter Zijlstra wrote: > On Tue, Feb 14, 2023 at 05:30:46PM +0800, Zeng Heng wrote: > > > > I never remember the shutdown paths -- do we force wipe the PMU > > > registers somewhere before this? > > > > I have checked the panic process, and there is no wipe operation for PMU > > registers, > > > > which causes the watchdog bites. > > > > Do you mean we should directly disable PMU registers instead of calling > > `iret_to_self` to > > > > consume blocked NMI interrupts ? > > If you don't wipe the PMU, there will be many and continuous NMIs, a > single IRET-to-SELF isn't going to safe you. > > Anyway, I had a bit of a grep around and I find we have: > > kernel/events/core.c: register_reboot_notifier(&perf_reboot_notifier); > > which should end up killing all the PMU activity. Somewhere around there > there's also a CONFIG_KEXEC_CORE ifdef, so I'm thinking it gets called > on the panic->crash-kernel path too? No, reboot_notifier_list is only handled in kexec reboot/reboot path, please see kernel_restart_prepare() invocation. Kdump path only shutdown key component like cpu, interrupt controller. > > If not, someone should look at doing something there. > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
