From da007f171fc9dd993d03a360b515cac1c87921bb Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Wed, 25 May 2022 00:21:18 +0300 Subject: kernel/reboot: Change registration order of legacy power-off handler 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 Tested-by: Geert Uytterhoeven Signed-off-by: Dmitry Osipenko Signed-off-by: Rafael J. Wysocki --- kernel/reboot.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/kernel/reboot.c b/kernel/reboot.c index bdb635842ec8..d4aa372c0cdc 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; } -- cgit v1.2.3