Re: [PATCH 21/30] panic: Introduce the panic pre-reboot notifier list

[Corey Minyard]

On Wed, Apr 27, 2022 at 07:49:15PM -0300, Guilherme G. Piccoli wrote:
> This patch renames the panic_notifier_list to panic_pre_reboot_list;
> the idea is that a subsequent patch will refactor the panic path
> in order to better split the notifiers, running some of them very
> early, some of them not so early [but still before kmsg_dump()] and
> finally, the rest should execute late, after kdump. The latter ones
> are now in the panic pre-reboot list - the name comes from the idea
> that these notifiers execute before panic() attempts rebooting the
> machine (if that option is set).
> 
> We also took the opportunity to clean-up useless header inclusions,
> improve some notifier block declarations (e.g. in ibmasm/heartbeat.c)
> and more important, change some priorities - we hereby set 2 notifiers
> to run late in the list [iss_panic_event() and the IPMI panic_event()]
> due to the risks they offer (may not return, for example).
> Proper documentation is going to be provided in a subsequent patch,
> that effectively refactors the panic path.

For the IPMI portion:

Acked-by: Corey Minyard <cminyard@xxxxxxxxxx>

Note that the IPMI panic_event() should always return, but it may take
some time, especially if the IPMI controller is no longer functional.
So the risk of a long delay is there and it makes sense to move it very
late.

-corey

> 
> Cc: Alex Elder <elder@xxxxxxxxxx>
> Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
> Cc: Anton Ivanov <anton.ivanov@xxxxxxxxxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: Chris Zankel <chris@xxxxxxxxxx>
> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
> Cc: Corey Minyard <minyard@xxxxxxx>
> Cc: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Helge Deller <deller@xxxxxx>
> Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> Cc: James Morse <james.morse@xxxxxxx>
> Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
> Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Cc: Matt Turner <mattst88@xxxxxxxxx>
> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Pavel Machek <pavel@xxxxxx>
> Cc: Richard Henderson <rth@xxxxxxxxxxx>
> Cc: Richard Weinberger <richard@xxxxxx>
> Cc: Robert Richter <rric@xxxxxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
> Cc: Tony Luck <tony.luck@xxxxxxxxx>
> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Cc: Wei Liu <wei.liu@xxxxxxxxxx>
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx>
> ---
> 
> Notice that, with this name change, out-of-tree code that relies in the global
> exported "panic_notifier_list" will fail to build. We could easily keep the
> retro-compatibility by making the old symbol to still exist and point to the
> pre_reboot list (or even, keep the old naming).
> 
> But our design choice was to allow the breakage, making users rethink their
> notifiers, adding them in the list that fits best. If that wasn't a good
> decision, we're open to change it, of course.
> Thanks in advance for the review!
> 
>  arch/alpha/kernel/setup.c             |  4 ++--
>  arch/parisc/kernel/pdc_chassis.c      |  3 +--
>  arch/powerpc/kernel/setup-common.c    |  2 +-
>  arch/s390/kernel/ipl.c                |  4 ++--
>  arch/um/drivers/mconsole_kern.c       |  2 +-
>  arch/um/kernel/um_arch.c              |  2 +-
>  arch/x86/xen/enlighten.c              |  2 +-
>  arch/xtensa/platforms/iss/setup.c     |  4 ++--
>  drivers/char/ipmi/ipmi_msghandler.c   | 12 +++++++-----
>  drivers/edac/altera_edac.c            |  3 +--
>  drivers/hv/vmbus_drv.c                |  4 ++--
>  drivers/leds/trigger/ledtrig-panic.c  |  3 +--
>  drivers/misc/ibmasm/heartbeat.c       | 16 +++++++++-------
>  drivers/net/ipa/ipa_smp2p.c           |  5 ++---
>  drivers/parisc/power.c                |  4 ++--
>  drivers/remoteproc/remoteproc_core.c  |  6 ++++--
>  drivers/s390/char/con3215.c           |  2 +-
>  drivers/s390/char/con3270.c           |  2 +-
>  drivers/s390/char/sclp_con.c          |  2 +-
>  drivers/s390/char/sclp_vt220.c        |  2 +-
>  drivers/staging/olpc_dcon/olpc_dcon.c |  6 ++++--
>  drivers/video/fbdev/hyperv_fb.c       |  4 ++--
>  include/linux/panic_notifier.h        |  2 +-
>  kernel/panic.c                        |  9 ++++-----
>  24 files changed, 54 insertions(+), 51 deletions(-)
> 
> diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
> index d88bdf852753..8ace0d7113b6 100644
> --- a/arch/alpha/kernel/setup.c
> +++ b/arch/alpha/kernel/setup.c
> @@ -472,8 +472,8 @@ setup_arch(char **cmdline_p)
>  	}
>  
>  	/* Register a call for panic conditions. */
> -	atomic_notifier_chain_register(&panic_notifier_list,
> -			&alpha_panic_block);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
> +					&alpha_panic_block);
>  
>  #ifndef alpha_using_srm
>  	/* Assume that we've booted from SRM if we haven't booted from MILO.
> diff --git a/arch/parisc/kernel/pdc_chassis.c b/arch/parisc/kernel/pdc_chassis.c
> index da154406d368..0fd8d87fb4f9 100644
> --- a/arch/parisc/kernel/pdc_chassis.c
> +++ b/arch/parisc/kernel/pdc_chassis.c
> @@ -22,7 +22,6 @@
>  #include <linux/kernel.h>
>  #include <linux/panic_notifier.h>
>  #include <linux/reboot.h>
> -#include <linux/notifier.h>
>  #include <linux/cache.h>
>  #include <linux/proc_fs.h>
>  #include <linux/seq_file.h>
> @@ -135,7 +134,7 @@ void __init parisc_pdc_chassis_init(void)
>  				PDC_CHASSIS_VER);
>  
>  		/* initialize panic notifier chain */
> -		atomic_notifier_chain_register(&panic_notifier_list,
> +		atomic_notifier_chain_register(&panic_pre_reboot_list,
>  				&pdc_chassis_panic_block);
>  
>  		/* initialize reboot notifier chain */
> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
> index d04b8bf8dbc7..3518bebc10ad 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -762,7 +762,7 @@ void __init setup_panic(void)
>  
>  	/* Low-level platform-specific routines that should run on panic */
>  	if (ppc_md.panic)
> -		atomic_notifier_chain_register(&panic_notifier_list,
> +		atomic_notifier_chain_register(&panic_pre_reboot_list,
>  					       &ppc_panic_block);
>  }
>  
> diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
> index 1cc85b8ff42e..4a88c5bb6e15 100644
> --- a/arch/s390/kernel/ipl.c
> +++ b/arch/s390/kernel/ipl.c
> @@ -2034,7 +2034,7 @@ static int on_panic_notify(struct notifier_block *self,
>  			   unsigned long event, void *data)
>  {
>  	do_panic();
> -	return NOTIFY_OK;
> +	return NOTIFY_DONE;
>  }
>  
>  static struct notifier_block on_panic_nb = {
> @@ -2069,7 +2069,7 @@ void __init setup_ipl(void)
>  		/* We have no info to copy */
>  		break;
>  	}
> -	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb);
>  }
>  
>  void s390_reset_system(void)
> diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
> index 2ea0421bcc3f..21c13b4e24a3 100644
> --- a/arch/um/drivers/mconsole_kern.c
> +++ b/arch/um/drivers/mconsole_kern.c
> @@ -855,7 +855,7 @@ static struct notifier_block panic_exit_notifier = {
>  
>  static int add_notifier(void)
>  {
> -	atomic_notifier_chain_register(&panic_notifier_list,
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
>  			&panic_exit_notifier);
>  	return 0;
>  }
> diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
> index 4485b1a7c8e4..fc6e443299da 100644
> --- a/arch/um/kernel/um_arch.c
> +++ b/arch/um/kernel/um_arch.c
> @@ -257,7 +257,7 @@ static struct notifier_block panic_exit_notifier = {
>  
>  void uml_finishsetup(void)
>  {
> -	atomic_notifier_chain_register(&panic_notifier_list,
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
>  				       &panic_exit_notifier);
>  
>  	uml_postsetup();
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index 30c6e986a6cd..d4f4de239a21 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -290,7 +290,7 @@ static struct notifier_block xen_panic_block = {
>  
>  int xen_panic_handler_init(void)
>  {
> -	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &xen_panic_block);
>  	return 0;
>  }
>  
> diff --git a/arch/xtensa/platforms/iss/setup.c b/arch/xtensa/platforms/iss/setup.c
> index d3433e1bb94e..eeeeb6cff6bd 100644
> --- a/arch/xtensa/platforms/iss/setup.c
> +++ b/arch/xtensa/platforms/iss/setup.c
> @@ -13,7 +13,6 @@
>   */
>  #include <linux/init.h>
>  #include <linux/kernel.h>
> -#include <linux/notifier.h>
>  #include <linux/panic_notifier.h>
>  #include <linux/printk.h>
>  #include <linux/string.h>
> @@ -53,6 +52,7 @@ iss_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
>  
>  static struct notifier_block iss_panic_block = {
>  	.notifier_call = iss_panic_event,
> +	.priority = INT_MIN, /* run as late as possible, may not return */
>  };
>  
>  void __init platform_setup(char **p_cmdline)
> @@ -81,5 +81,5 @@ void __init platform_setup(char **p_cmdline)
>  		}
>  	}
>  
> -	atomic_notifier_chain_register(&panic_notifier_list, &iss_panic_block);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &iss_panic_block);
>  }
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> index c59265146e9c..6c4770949c01 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -25,7 +25,6 @@
>  #include <linux/slab.h>
>  #include <linux/ipmi.h>
>  #include <linux/ipmi_smi.h>
> -#include <linux/notifier.h>
>  #include <linux/init.h>
>  #include <linux/proc_fs.h>
>  #include <linux/rcupdate.h>
> @@ -5375,10 +5374,13 @@ static int ipmi_register_driver(void)
>  	return rv;
>  }
>  
> +/*
> + * we should execute this panic callback late, since it involves
> + * a complex call-chain and panic() runs in atomic context.
> + */
>  static struct notifier_block panic_block = {
>  	.notifier_call	= panic_event,
> -	.next		= NULL,
> -	.priority	= 200	/* priority: INT_MAX >= x >= 0 */
> +	.priority	= INT_MIN + 1,
>  };
>  
>  static int ipmi_init_msghandler(void)
> @@ -5406,7 +5408,7 @@ static int ipmi_init_msghandler(void)
>  	timer_setup(&ipmi_timer, ipmi_timeout, 0);
>  	mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
>  
> -	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &panic_block);
>  
>  	initialized = true;
>  
> @@ -5438,7 +5440,7 @@ static void __exit cleanup_ipmi(void)
>  	if (initialized) {
>  		destroy_workqueue(remove_work_wq);
>  
> -		atomic_notifier_chain_unregister(&panic_notifier_list,
> +		atomic_notifier_chain_unregister(&panic_pre_reboot_list,
>  						 &panic_block);
>  
>  		/*
> diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
> index e7e8e624a436..4890e9cba6fb 100644
> --- a/drivers/edac/altera_edac.c
> +++ b/drivers/edac/altera_edac.c
> @@ -16,7 +16,6 @@
>  #include <linux/kernel.h>
>  #include <linux/mfd/altera-sysmgr.h>
>  #include <linux/mfd/syscon.h>
> -#include <linux/notifier.h>
>  #include <linux/of_address.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
> @@ -2163,7 +2162,7 @@ static int altr_edac_a10_probe(struct platform_device *pdev)
>  		int dberror, err_addr;
>  
>  		edac->panic_notifier.notifier_call = s10_edac_dberr_handler;
> -		atomic_notifier_chain_register(&panic_notifier_list,
> +		atomic_notifier_chain_register(&panic_pre_reboot_list,
>  					       &edac->panic_notifier);
>  
>  		/* Printout a message if uncorrectable error previously. */
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 901b97034308..3717c323aa36 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1622,7 +1622,7 @@ static int vmbus_bus_init(void)
>  	 * Always register the vmbus unload panic notifier because we
>  	 * need to shut the VMbus channel connection on panic.
>  	 */
> -	atomic_notifier_chain_register(&panic_notifier_list,
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
>  			       &hyperv_panic_vmbus_unload_block);
>  
>  	vmbus_request_offers();
> @@ -2851,7 +2851,7 @@ static void __exit vmbus_exit(void)
>  	 * The vmbus panic notifier is always registered, hence we should
>  	 * also unconditionally unregister it here as well.
>  	 */
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
>  					&hyperv_panic_vmbus_unload_block);
>  
>  	free_page((unsigned long)hv_panic_page);
> diff --git a/drivers/leds/trigger/ledtrig-panic.c b/drivers/leds/trigger/ledtrig-panic.c
> index 64abf2e91608..34fd5170723f 100644
> --- a/drivers/leds/trigger/ledtrig-panic.c
> +++ b/drivers/leds/trigger/ledtrig-panic.c
> @@ -7,7 +7,6 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/init.h>
> -#include <linux/notifier.h>
>  #include <linux/panic_notifier.h>
>  #include <linux/leds.h>
>  #include "../leds.h"
> @@ -64,7 +63,7 @@ static long led_panic_blink(int state)
>  
>  static int __init ledtrig_panic_init(void)
>  {
> -	atomic_notifier_chain_register(&panic_notifier_list,
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
>  				       &led_trigger_panic_nb);
>  
>  	led_trigger_register_simple("panic", &trigger);
> diff --git a/drivers/misc/ibmasm/heartbeat.c b/drivers/misc/ibmasm/heartbeat.c
> index 59c9a0d95659..d6acae88b722 100644
> --- a/drivers/misc/ibmasm/heartbeat.c
> +++ b/drivers/misc/ibmasm/heartbeat.c
> @@ -8,7 +8,6 @@
>   * Author: Max Asböck <amax@xxxxxxxxxx>
>   */
>  
> -#include <linux/notifier.h>
>  #include <linux/panic_notifier.h>
>  #include "ibmasm.h"
>  #include "dot_command.h"
> @@ -24,7 +23,7 @@ static int suspend_heartbeats = 0;
>   * In the case of a panic the interrupt handler continues to work and thus
>   * continues to respond to heartbeats, making the service processor believe
>   * the OS is still running and thus preventing a reboot.
> - * To prevent this from happening a callback is added the panic_notifier_list.
> + * To prevent this from happening a callback is added in a panic notifier list.
>   * Before responding to a heartbeat the driver checks if a panic has happened,
>   * if yes it suspends heartbeat, causing the service processor to reboot as
>   * expected.
> @@ -32,20 +31,23 @@ static int suspend_heartbeats = 0;
>  static int panic_happened(struct notifier_block *n, unsigned long val, void *v)
>  {
>  	suspend_heartbeats = 1;
> -	return 0;
> +	return NOTIFY_DONE;
>  }
>  
> -static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };
> +static struct notifier_block panic_notifier = {
> +	.notifier_call = panic_happened,
> +};
>  
>  void ibmasm_register_panic_notifier(void)
>  {
> -	atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
> +					&panic_notifier);
>  }
>  
>  void ibmasm_unregister_panic_notifier(void)
>  {
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> -			&panic_notifier);
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
> +					&panic_notifier);
>  }
>  
>  
> diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
> index 211233612039..92cdf6e0637c 100644
> --- a/drivers/net/ipa/ipa_smp2p.c
> +++ b/drivers/net/ipa/ipa_smp2p.c
> @@ -7,7 +7,6 @@
>  #include <linux/types.h>
>  #include <linux/device.h>
>  #include <linux/interrupt.h>
> -#include <linux/notifier.h>
>  #include <linux/panic_notifier.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/soc/qcom/smem.h>
> @@ -138,13 +137,13 @@ static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p)
>  	smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier;
>  	smp2p->panic_notifier.priority = INT_MAX;	/* Do it early */
>  
> -	return atomic_notifier_chain_register(&panic_notifier_list,
> +	return atomic_notifier_chain_register(&panic_pre_reboot_list,
>  					      &smp2p->panic_notifier);
>  }
>  
>  static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
>  {
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
>  					 &smp2p->panic_notifier);
>  }
>  
> diff --git a/drivers/parisc/power.c b/drivers/parisc/power.c
> index 8512884de2cf..5bb0868f5f08 100644
> --- a/drivers/parisc/power.c
> +++ b/drivers/parisc/power.c
> @@ -233,7 +233,7 @@ static int __init power_init(void)
>  	}
>  
>  	/* Register a call for panic conditions. */
> -	atomic_notifier_chain_register(&panic_notifier_list,
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
>  			&parisc_panic_block);
>  
>  	return 0;
> @@ -243,7 +243,7 @@ static void __exit power_exit(void)
>  {
>  	kthread_stop(power_task);
>  
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
>  			&parisc_panic_block);
>  
>  	pdc_soft_power_button(0);
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index c510125769b9..24799ff239e6 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -2795,12 +2795,14 @@ static int rproc_panic_handler(struct notifier_block *nb, unsigned long event,
>  static void __init rproc_init_panic(void)
>  {
>  	rproc_panic_nb.notifier_call = rproc_panic_handler;
> -	atomic_notifier_chain_register(&panic_notifier_list, &rproc_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
> +				       &rproc_panic_nb);
>  }
>  
>  static void __exit rproc_exit_panic(void)
>  {
> -	atomic_notifier_chain_unregister(&panic_notifier_list, &rproc_panic_nb);
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
> +					 &rproc_panic_nb);
>  }
>  
>  static int __init remoteproc_init(void)
> diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
> index 192198bd3dc4..07379dd3f1f3 100644
> --- a/drivers/s390/char/con3215.c
> +++ b/drivers/s390/char/con3215.c
> @@ -867,7 +867,7 @@ static int __init con3215_init(void)
>  		raw3215[0] = NULL;
>  		return -ENODEV;
>  	}
> -	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb);
>  	register_reboot_notifier(&on_reboot_nb);
>  	register_console(&con3215);
>  	return 0;
> diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c
> index 476202f3d8a0..e79bf3e7bde3 100644
> --- a/drivers/s390/char/con3270.c
> +++ b/drivers/s390/char/con3270.c
> @@ -645,7 +645,7 @@ con3270_init(void)
>  	condev->cline->len = 0;
>  	con3270_create_status(condev);
>  	condev->input = alloc_string(&condev->freemem, 80);
> -	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb);
>  	register_reboot_notifier(&on_reboot_nb);
>  	register_console(&con3270);
>  	return 0;
> diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c
> index e5d947c763ea..7ca9d4c45d60 100644
> --- a/drivers/s390/char/sclp_con.c
> +++ b/drivers/s390/char/sclp_con.c
> @@ -288,7 +288,7 @@ sclp_console_init(void)
>  	timer_setup(&sclp_con_timer, sclp_console_timeout, 0);
>  
>  	/* enable printk-access to this driver */
> -	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb);
>  	register_reboot_notifier(&on_reboot_nb);
>  	register_console(&sclp_console);
>  	return 0;
> diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
> index a32f34a1c6d2..97cf9e290c28 100644
> --- a/drivers/s390/char/sclp_vt220.c
> +++ b/drivers/s390/char/sclp_vt220.c
> @@ -838,7 +838,7 @@ sclp_vt220_con_init(void)
>  	if (rc)
>  		return rc;
>  	/* Attach linux console */
> -	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb);
>  	register_reboot_notifier(&on_reboot_nb);
>  	register_console(&sclp_vt220_console);
>  	return 0;
> diff --git a/drivers/staging/olpc_dcon/olpc_dcon.c b/drivers/staging/olpc_dcon/olpc_dcon.c
> index 7284cb4ac395..cb50471f2246 100644
> --- a/drivers/staging/olpc_dcon/olpc_dcon.c
> +++ b/drivers/staging/olpc_dcon/olpc_dcon.c
> @@ -653,7 +653,8 @@ static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	}
>  
>  	register_reboot_notifier(&dcon->reboot_nb);
> -	atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
> +				       &dcon_panic_nb);
>  
>  	return 0;
>  
> @@ -676,7 +677,8 @@ static int dcon_remove(struct i2c_client *client)
>  	struct dcon_priv *dcon = i2c_get_clientdata(client);
>  
>  	unregister_reboot_notifier(&dcon->reboot_nb);
> -	atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
> +					 &dcon_panic_nb);
>  
>  	free_irq(DCON_IRQ, dcon);
>  
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> index f3494b868a64..ec21e63592be 100644
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ b/drivers/video/fbdev/hyperv_fb.c
> @@ -1253,7 +1253,7 @@ static int hvfb_probe(struct hv_device *hdev,
>  	 */
>  	par->hvfb_panic_nb.notifier_call = hvfb_on_panic;
>  	par->hvfb_panic_nb.priority = INT_MIN + 10,
> -	atomic_notifier_chain_register(&panic_notifier_list,
> +	atomic_notifier_chain_register(&panic_pre_reboot_list,
>  				       &par->hvfb_panic_nb);
>  
>  	return 0;
> @@ -1276,7 +1276,7 @@ static int hvfb_remove(struct hv_device *hdev)
>  	struct fb_info *info = hv_get_drvdata(hdev);
>  	struct hvfb_par *par = info->par;
>  
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> +	atomic_notifier_chain_unregister(&panic_pre_reboot_list,
>  					 &par->hvfb_panic_nb);
>  
>  	par->update = false;
> diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h
> index 7364a346bcb0..7912aacbc0e5 100644
> --- a/include/linux/panic_notifier.h
> +++ b/include/linux/panic_notifier.h
> @@ -5,9 +5,9 @@
>  #include <linux/notifier.h>
>  #include <linux/types.h>
>  
> -extern struct atomic_notifier_head panic_notifier_list;
>  extern struct atomic_notifier_head panic_hypervisor_list;
>  extern struct atomic_notifier_head panic_info_list;
> +extern struct atomic_notifier_head panic_pre_reboot_list;
>  
>  extern bool crash_kexec_post_notifiers;
>  
> diff --git a/kernel/panic.c b/kernel/panic.c
> index 73ca1bc44e30..a9d43b98b05b 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -69,16 +69,15 @@ EXPORT_SYMBOL_GPL(panic_timeout);
>  #define PANIC_PRINT_ALL_CPU_BT		0x00000040
>  unsigned long panic_print;
>  
> -ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
> -
> -EXPORT_SYMBOL(panic_notifier_list);
> -
>  ATOMIC_NOTIFIER_HEAD(panic_hypervisor_list);
>  EXPORT_SYMBOL(panic_hypervisor_list);
>  
>  ATOMIC_NOTIFIER_HEAD(panic_info_list);
>  EXPORT_SYMBOL(panic_info_list);
>  
> +ATOMIC_NOTIFIER_HEAD(panic_pre_reboot_list);
> +EXPORT_SYMBOL(panic_pre_reboot_list);
> +
>  static long no_blink(int state)
>  {
>  	return 0;
> @@ -295,7 +294,7 @@ void panic(const char *fmt, ...)
>  	 */
>  	atomic_notifier_call_chain(&panic_hypervisor_list, PANIC_NOTIFIER, buf);
>  	atomic_notifier_call_chain(&panic_info_list, PANIC_NOTIFIER, buf);
> -	atomic_notifier_call_chain(&panic_notifier_list, PANIC_NOTIFIER, buf);
> +	atomic_notifier_call_chain(&panic_pre_reboot_list, PANIC_NOTIFIER, buf);
>  
>  	panic_print_sys_info(false);
>  
> -- 
> 2.36.0
>