Linux-Kernel Archive: Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list From: Petr Mladek Date: Mon May 16 2022 - 10:02:10 EST Next message: Damien Le Moal: "Re: [dm-devel] [PATCH v4 03/13] nvme: zns: Allow ZNS drives that have non-power_of_2 zone size" Previous message: Yang Yingliang: "Re: [PATCH 4.9/4.14/4.19/5.4] tty/serial: digicolor: fix possible null-ptr-deref in digicolor_uart_probe()" Next in thread: Guilherme G. Piccoli: "Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On Wed 2022-04-27 19:49:13, Guilherme G. Piccoli wrote: > The goal of this new panic notifier is to allow its users to register > callbacks to run very early in the panic path. This aims hypervisor/FW > notification mechanisms as well as simple LED functions, and any other > simple and safe mechanism that should run early in the panic path; more > dangerous callbacks should execute later. > > For now, the patch is almost a no-op (although it changes a bit the > ordering in which some panic notifiers are executed). In a subsequent > patch, the panic path will be refactored, then the panic hypervisor > notifiers will effectively run very early in the panic path. > > We also defer documenting it all properly in the subsequent refactor > patch. While at it, we removed some useless header inclusions and > fixed some notifiers return too (by using the standard NOTIFY_DONE). > --- a/arch/mips/sgi-ip22/ip22-reset.c > +++ b/arch/mips/sgi-ip22/ip22-reset.c > @@ -195,7 +195,7 @@ static int __init reboot_setup(void) > } > > timer_setup(&blink_timer, blink_timeout, 0); > - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); > + atomic_notifier_chain_register(&panic_hypervisor_list, &panic_block); This notifier enables blinking. It is not much safe. It calls mod_timer() that takes a lock internally. This kind of functionality should go into the last list called before panic() enters the infinite loop. IMHO, all the blinking stuff should go there. > > return 0; > } > diff --git a/arch/mips/sgi-ip32/ip32-reset.c b/arch/mips/sgi-ip32/ip32-reset.c > index 18d1c115cd53..9ee1302c9d13 100644 > --- a/arch/mips/sgi-ip32/ip32-reset.c > +++ b/arch/mips/sgi-ip32/ip32-reset.c > @@ -145,7 +144,7 @@ static __init int ip32_reboot_setup(void) > pm_power_off = ip32_machine_halt; > > timer_setup(&blink_timer, blink_timeout, 0); > - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); > + atomic_notifier_chain_register(&panic_hypervisor_list, &panic_block); Same here. Should be done only before the "loop". > > return 0; > } > --- a/drivers/firmware/google/gsmi.c > +++ b/drivers/firmware/google/gsmi.c > @@ -1034,7 +1034,7 @@ static __init int gsmi_init(void) > > register_reboot_notifier(&gsmi_reboot_notifier); > register_die_notifier(&gsmi_die_notifier); > - atomic_notifier_chain_register(&panic_notifier_list, > + atomic_notifier_chain_register(&panic_hypervisor_list, > &gsmi_panic_notifier); I am not sure about this one. It looks like some logging or pre_reboot stuff. > > printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n"); > --- a/drivers/leds/trigger/ledtrig-activity.c > +++ b/drivers/leds/trigger/ledtrig-activity.c > @@ -247,7 +247,7 @@ static int __init activity_init(void) > int rc = led_trigger_register(&activity_led_trigger); > > if (!rc) { > - atomic_notifier_chain_register(&panic_notifier_list, > + atomic_notifier_chain_register(&panic_hypervisor_list, > &activity_panic_nb); The notifier is trivial. It just sets a variable. But still, it is about blinking and should be done in the last "loop" list. > register_reboot_notifier(&activity_reboot_nb); > } > --- a/drivers/leds/trigger/ledtrig-heartbeat.c > +++ b/drivers/leds/trigger/ledtrig-heartbeat.c > @@ -190,7 +190,7 @@ static int __init heartbeat_trig_init(void) > int rc = led_trigger_register(&heartbeat_led_trigger); > > if (!rc) { > - atomic_notifier_chain_register(&panic_notifier_list, > + atomic_notifier_chain_register(&panic_hypervisor_list, > &heartbeat_panic_nb); Same here. Blinking => loop list. > register_reboot_notifier(&heartbeat_reboot_nb); > } > diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c > index a16b99bdaa13..d9d5199cdb2b 100644 > --- a/drivers/misc/bcm-vk/bcm_vk_dev.c > +++ b/drivers/misc/bcm-vk/bcm_vk_dev.c > @@ -1446,7 +1446,7 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent) > > /* register for panic notifier */ > vk->panic_nb.notifier_call = bcm_vk_on_panic; > - err = atomic_notifier_chain_register(&panic_notifier_list, > + err = atomic_notifier_chain_register(&panic_hypervisor_list, > &vk->panic_nb); It seems to reset some hardware or so. IMHO, it should go into the pre-reboot list. > if (err) { > dev_err(dev, "Fail to register panic notifier\n"); > --- a/drivers/power/reset/ltc2952-poweroff.c > +++ b/drivers/power/reset/ltc2952-poweroff.c > @@ -279,7 +279,7 @@ static int ltc2952_poweroff_probe(struct platform_device *pdev) > pm_power_off = ltc2952_poweroff_kill; > > data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic; > - atomic_notifier_chain_register(&panic_notifier_list, > + atomic_notifier_chain_register(&panic_hypervisor_list, > &data->panic_notifier); I looks like this somehow triggers the reboot. IMHO, it should go into the pre_reboot list. > dev_info(&pdev->dev, "probe successful\n"); > > --- a/drivers/soc/bcm/brcmstb/pm/pm-arm.c > +++ b/drivers/soc/bcm/brcmstb/pm/pm-arm.c > @@ -814,7 +814,7 @@ static int brcmstb_pm_probe(struct platform_device *pdev) > goto out; > } > > - atomic_notifier_chain_register(&panic_notifier_list, > + atomic_notifier_chain_register(&panic_hypervisor_list, > &brcmstb_pm_panic_nb); I am not sure about this one. It instruct some HW to preserve DRAM. IMHO, it better fits into pre_reboot category but I do not have strong opinion. > > pm_power_off = brcmstb_pm_poweroff; Best Regards, Petr Next message: Damien Le Moal: "Re: [dm-devel] [PATCH v4 03/13] nvme: zns: Allow ZNS drives that have non-power_of_2 zone size" Previous message: Yang Yingliang: "Re: [PATCH 4.9/4.14/4.19/5.4] tty/serial: digicolor: fix possible null-ptr-deref in digicolor_uart_probe()" Next in thread: Guilherme G. Piccoli: "Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
