Commit ee13240c authored by Feng Tang's avatar Feng Tang Committed by Andrew Morton
Browse files

panic: add note that panic_print sysctl interface is deprecated 

Add a dedicated core parameter 'panic_console_replay' for controlling
console replay, and add note that 'panic_print' sysctl interface will be
obsoleted by 'panic_sys_info' and 'panic_console_replay'.  When it
happens, the SYS_INFO_PANIC_CONSOLE_REPLAY can be removed as well.

Link: https://lkml.kernel.org/r/20250703021004.42328-6-feng.tang@linux.alibaba.com


Signed-off-by: default avatarFeng Tang <feng.tang@linux.alibaba.com>
Suggested-by: default avatarPetr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9743d12d

Documentation/admin-guide/kernel-parameters.txt

+4 −0
Original line number Diff line number Diff line
@@ -4578,6 +4578,10 @@ 


                        This is a human readable alternative to the 'panic_print' option.



	panic_console_replay

			When panic happens, replay all kernel messages on

			consoles at the end of panic.



	parkbd.port=	[HW] Parallel port number the keyboard adapter is

			connected to, default is 0.

			Format: <parport#>

kernel/panic.c

+13 −8
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ int panic_on_warn __read_mostly; 
unsigned long panic_on_taint;

bool panic_on_taint_nousertaint = false;

static unsigned int warn_limit __read_mostly;

static bool panic_console_replay;



bool panic_triggering_all_cpu_backtrace;
@@ -77,6 +78,13 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list); 
EXPORT_SYMBOL(panic_notifier_list);



#ifdef CONFIG_SYSCTL

static int sysctl_panic_print_handler(const struct ctl_table *table, int write,

			   void *buffer, size_t *lenp, loff_t *ppos)

{

	pr_info_once("Kernel: 'panic_print' sysctl interface will be obsoleted by both 'panic_sys_info' and 'panic_console_replay'\n");

	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);

}



static const struct ctl_table kern_panic_table[] = {

#ifdef CONFIG_SMP

	{
@@ -108,7 +116,7 @@ static const struct ctl_table kern_panic_table[] = { 
		.data		= &panic_print,

		.maxlen		= sizeof(unsigned long),

		.mode		= 0644,

		.proc_handler	= proc_doulongvec_minmax,

		.proc_handler	= sysctl_panic_print_handler,

	},

	{

		.procname	= "panic_on_warn",
@@ -247,12 +255,6 @@ void nmi_panic(struct pt_regs *regs, const char *msg) 
}

EXPORT_SYMBOL(nmi_panic);



static void panic_console_replay(void)

{

	if (panic_print & SYS_INFO_PANIC_CONSOLE_REPLAY)

		console_flush_on_panic(CONSOLE_REPLAY_ALL);

}



void check_panic_on_warn(const char *origin)

{

	unsigned int limit;
@@ -427,7 +429,9 @@ void panic(const char *fmt, ...) 
	debug_locks_off();

	console_flush_on_panic(CONSOLE_FLUSH_PENDING);



	panic_console_replay();

	if ((panic_print & SYS_INFO_PANIC_CONSOLE_REPLAY) ||

		panic_console_replay)

		console_flush_on_panic(CONSOLE_REPLAY_ALL);



	if (!panic_blink)

		panic_blink = no_blink;
@@ -869,6 +873,7 @@ core_param(panic_print, panic_print, ulong, 0644); 
core_param(pause_on_oops, pause_on_oops, int, 0644);

core_param(panic_on_warn, panic_on_warn, int, 0644);

core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);

core_param(panic_console_replay, panic_console_replay, bool, 0644);



static int __init oops_setup(char *s)

{