Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Wed, 25 May 2022 14:56:55 +0200 | Subject | Re: [PATCH v1] kernel/reboot: Change registration order of legacy power-off handler |
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On Tue, May 24, 2022 at 11:23 PM Dmitry Osipenko <dmitry.osipenko@collabora.com> wrote: > > We're unconditionally registering sys-off handler for the legacy > pm_power_off() callback, this causes problem for platforms that don't > use power-off handlers at all and should be halted. Now reboot syscall > assumes that there is a power-off handler installed and tries to power > off system instead of halting it. > > To fix the trouble, move the handler's registration to the reboot syscall > and check the pm_power_off() presence. > > Fixes: 0e2110d2e910 ("kernel/reboot: Add kernel_can_power_off()") > Reported-by: Geert Uytterhoeven <geert+renesas@glider.be> > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> > Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> > --- > kernel/reboot.c | 33 +++++++++++++++++---------------- > 1 file changed, 17 insertions(+), 16 deletions(-) > > diff --git a/kernel/reboot.c b/kernel/reboot.c > index 0bdc64ecf4f6..a091145ee710 100644 > --- a/kernel/reboot.c > +++ b/kernel/reboot.c > @@ -569,22 +569,6 @@ static int legacy_pm_power_off(struct sys_off_data *data) > return NOTIFY_DONE; > } > > -/* > - * Register sys-off handlers for legacy PM callbacks. This allows legacy > - * PM callbacks co-exist with the new sys-off API. > - * > - * TODO: Remove legacy handlers once all legacy PM users will be switched > - * to the sys-off based APIs. > - */ > -static int __init legacy_pm_init(void) > -{ > - register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT, > - legacy_pm_power_off, NULL); > - > - return 0; > -} > -core_initcall(legacy_pm_init); > - > static void do_kernel_power_off_prepare(void) > { > blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL); > @@ -646,6 +630,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, > void __user *, arg) > { > struct pid_namespace *pid_ns = task_active_pid_ns(current); > + struct sys_off_handler *sys_off = NULL; > char buffer[256]; > int ret = 0; > > @@ -670,6 +655,21 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, > if (ret) > return ret; > > + /* > + * Register sys-off handlers for legacy PM callback. This allows > + * legacy PM callbacks temporary co-exist with the new sys-off API. > + * > + * TODO: Remove legacy handlers once all legacy PM users will be > + * switched to the sys-off based APIs. > + */ > + if (pm_power_off) { > + sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, > + SYS_OFF_PRIO_DEFAULT, > + legacy_pm_power_off, NULL); > + if (IS_ERR(sys_off)) > + return PTR_ERR(sys_off); > + } > + > /* Instead of trying to make the power_off code look like > * halt when pm_power_off is not set do it the easy way. > */ > @@ -727,6 +727,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, > break; > } > mutex_unlock(&system_transition_mutex); > + unregister_sys_off_handler(sys_off); > return ret; > } > > --
Applied, thanks!
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