Commit 03ef32d6 authored by Feng Tang's avatar Feng Tang Committed by Andrew Morton
Browse files

sys_info: add a default kernel sys_info mask 

Which serves as a global default sys_info mask.  When users want the same
system information for many error cases (panic, hung, lockup ...), they
can chose to set this global knob only once, while not setting up each
individual sys_info knobs.

This just adds a 'lazy' option, and doesn't change existing kernel
behavior as the mask is 0 by default.

Link: https://lkml.kernel.org/r/20251113111039.22701-5-feng.tang@linux.alibaba.com


Suggested-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarFeng Tang <feng.tang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a9af76a7

Documentation/admin-guide/sysctl/kernel.rst

+9 −0
Original line number Diff line number Diff line
@@ -521,6 +521,15 @@ default), only processes with the CAP_SYS_ADMIN capability may create 
io_uring instances.





kernel_sys_info

===============

A comma separated list of extra system information to be dumped when

soft/hard lockup is detected, for example, "tasks,mem,timers,locks,...".

Refer 'panic_sys_info' section below for more details.



It serves as the default kernel control knob, which will take effect

when a kernel module calls sys_info() with parameter==0.



kexec_load_disabled

===================

lib/sys_info.c

+30 −1
Original line number Diff line number Diff line
@@ -24,6 +24,13 @@ static const char * const si_names[] = { 
	[ilog2(SYS_INFO_BLOCKED_TASKS)]		= "blocked_tasks",

};



/*

 * Default kernel sys_info mask.

 * If a kernel module calls sys_info() with "parameter == 0", then

 * this mask will be used.

 */

static unsigned long kernel_si_mask;



/* Expecting string like "xxx_sys_info=tasks,mem,timers,locks,ftrace,..." */

unsigned long sys_info_parse_param(char *str)

{
@@ -110,9 +117,26 @@ int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write, 
	else

		return sys_info_read_handler(&table, buffer, lenp, ppos, ro_table->data);

}



static const struct ctl_table sys_info_sysctls[] = {

	{

		.procname	= "kernel_sys_info",

		.data		= &kernel_si_mask,

		.maxlen         = sizeof(kernel_si_mask),

		.mode		= 0644,

		.proc_handler	= sysctl_sys_info_handler,

	},

};



static int __init sys_info_sysctl_init(void)

{

	register_sysctl_init("kernel", sys_info_sysctls);

	return 0;

}

subsys_initcall(sys_info_sysctl_init);

#endif



void sys_info(unsigned long si_mask)

static void __sys_info(unsigned long si_mask)

{

	if (si_mask & SYS_INFO_TASKS)

		show_state();
@@ -135,3 +159,8 @@ void sys_info(unsigned long si_mask) 
	if (si_mask & SYS_INFO_BLOCKED_TASKS)

		show_state_filter(TASK_UNINTERRUPTIBLE);

}



void sys_info(unsigned long si_mask)

{

	__sys_info(si_mask ? : kernel_si_mask);

}