Commit f117955a authored by Guilherme G. Piccoli's avatar Guilherme G. Piccoli Committed by Linus Torvalds
Browse files

kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases 

After a recent change introduced by Vlastimil's series [0], kernel is
able now to handle sysctl parameters on kernel command line; also, the
series introduced a simple infrastructure to convert legacy boot
parameters (that duplicate sysctls) into sysctl aliases.

This patch converts the watchdog parameters softlockup_panic and
{hard,soft}lockup_all_cpu_backtrace to use the new alias infrastructure.
It fixes the documentation too, since the alias only accepts values 0 or
1, not the full range of integers.

We also took the opportunity here to improve the documentation of the
previously converted hung_task_panic (see the patch series [0]) and put
the alias table in alphabetical order.

[0] http://lkml.kernel.org/r/20200427180433.7029-1-vbabka@suse.cz



Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@canonical.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Link: http://lkml.kernel.org/r/20200507214624.21911-1-gpiccoli@canonical.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4f2f682d

Documentation/admin-guide/kernel-parameters.txt

+5 −5
Original line number Diff line number Diff line
@@ -1445,7 +1445,7 @@ 
	hardlockup_all_cpu_backtrace=

			[KNL] Should the hard-lockup detector generate

			backtraces on all cpus.

			Format: <integer>

			Format: 0 | 1



	hashdist=	[KNL,NUMA] Large hashes allocated during boot

			are distributed across NUMA nodes.  Defaults on
@@ -1513,7 +1513,7 @@ 


	hung_task_panic=

			[KNL] Should the hung task detector generate panics.

			Format: <integer>

			Format: 0 | 1



			A value of 1 instructs the kernel to panic when a

			hung task is detected. The default value is controlled
@@ -4665,9 +4665,9 @@ 


	softlockup_panic=

			[KNL] Should the soft-lockup detector generate panics.

			Format: <integer>

			Format: 0 | 1



			A nonzero value instructs the soft-lockup detector

			A value of 1 instructs the soft-lockup detector

			to panic the machine when a soft-lockup occurs. It is

			also controlled by the kernel.softlockup_panic sysctl

			and CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC, which is the
@@ -4676,7 +4676,7 @@ 
	softlockup_all_cpu_backtrace=

			[KNL] Should the soft-lockup detector generate

			backtraces on all cpus.

			Format: <integer>

			Format: 0 | 1



	sonypi.*=	[HW] Sony Programmable I/O Control Device driver

			See Documentation/admin-guide/laptops/sonypi.rst

fs/proc/proc_sysctl.c

+5 −2
Original line number Diff line number Diff line
@@ -1720,8 +1720,11 @@ struct sysctl_alias { 
 * parameter.

 */

static const struct sysctl_alias sysctl_aliases[] = {

	{"numa_zonelist_order",		"vm.numa_zonelist_order" },

	{"hardlockup_all_cpu_backtrace",	"kernel.hardlockup_all_cpu_backtrace" },

	{"hung_task_panic",			"kernel.hung_task_panic" },

	{"numa_zonelist_order",			"vm.numa_zonelist_order" },

	{"softlockup_all_cpu_backtrace",	"kernel.softlockup_all_cpu_backtrace" },

	{"softlockup_panic",			"kernel.softlockup_panic" },

	{ }

};

kernel/watchdog.c

+9 −28
Original line number Diff line number Diff line
@@ -50,6 +50,11 @@ struct cpumask watchdog_cpumask __read_mostly; 
unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);



#ifdef CONFIG_HARDLOCKUP_DETECTOR



# ifdef CONFIG_SMP

int __read_mostly sysctl_hardlockup_all_cpu_backtrace;

# endif /* CONFIG_SMP */



/*

 * Should we panic when a soft-lockup or hard-lockup occurs:

 */
@@ -82,16 +87,6 @@ static int __init hardlockup_panic_setup(char *str) 
}

__setup("nmi_watchdog=", hardlockup_panic_setup);



# ifdef CONFIG_SMP

int __read_mostly sysctl_hardlockup_all_cpu_backtrace;



static int __init hardlockup_all_cpu_backtrace_setup(char *str)

{

	sysctl_hardlockup_all_cpu_backtrace = !!simple_strtol(str, NULL, 0);

	return 1;

}

__setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup);

# endif /* CONFIG_SMP */

#endif /* CONFIG_HARDLOCKUP_DETECTOR */



/*
@@ -163,6 +158,10 @@ static void lockup_detector_update_enable(void) 


#define SOFTLOCKUP_RESET	ULONG_MAX



#ifdef CONFIG_SMP

int __read_mostly sysctl_softlockup_all_cpu_backtrace;

#endif



/* Global variables, exported for sysctl */

unsigned int __read_mostly softlockup_panic =

			CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
@@ -178,13 +177,6 @@ static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); 
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);

static unsigned long soft_lockup_nmi_warn;



static int __init softlockup_panic_setup(char *str)

{

	softlockup_panic = simple_strtoul(str, NULL, 0);

	return 1;

}

__setup("softlockup_panic=", softlockup_panic_setup);



static int __init nowatchdog_setup(char *str)

{

	watchdog_user_enabled = 0;
@@ -206,17 +198,6 @@ static int __init watchdog_thresh_setup(char *str) 
}

__setup("watchdog_thresh=", watchdog_thresh_setup);



#ifdef CONFIG_SMP

int __read_mostly sysctl_softlockup_all_cpu_backtrace;



static int __init softlockup_all_cpu_backtrace_setup(char *str)

{

	sysctl_softlockup_all_cpu_backtrace = !!simple_strtol(str, NULL, 0);

	return 1;

}

__setup("softlockup_all_cpu_backtrace=", softlockup_all_cpu_backtrace_setup);

#endif



static void __lockup_detector_cleanup(void);



/*

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