From f117955a2255721a6a0e9cecf6cad3a6eb43cbc3 Mon Sep 17 00:00:00 2001 From: "Guilherme G. Piccoli" Date: Sun, 7 Jun 2020 21:40:42 -0700 Subject: [PATCH] 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: Guilherme G. Piccoli Signed-off-by: Andrew Morton Acked-by: Vlastimil Babka Cc: Kees Cook Cc: Iurii Zaikin Cc: Luis Chamberlain Link: http://lkml.kernel.org/r/20200507214624.21911-1-gpiccoli@canonical.com Signed-off-by: Linus Torvalds --- .../admin-guide/kernel-parameters.txt | 10 ++--- fs/proc/proc_sysctl.c | 7 +++- kernel/watchdog.c | 37 +++++-------------- 3 files changed, 19 insertions(+), 35 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0c72b5c22416..ed9597e37415 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1445,7 +1445,7 @@ hardlockup_all_cpu_backtrace= [KNL] Should the hard-lockup detector generate backtraces on all cpus. - Format: + 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: + 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: + 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: + Format: 0 | 1 sonypi.*= [HW] Sony Programmable I/O Control Device driver See Documentation/admin-guide/laptops/sonypi.rst diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 15030784566c..5b405f32971d 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1720,8 +1720,11 @@ struct sysctl_alias { * parameter. */ static const struct sysctl_alias sysctl_aliases[] = { - {"numa_zonelist_order", "vm.numa_zonelist_order" }, - {"hung_task_panic", "kernel.hung_task_panic" }, + {"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" }, { } }; diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 53ff2c81b084..5abb5b22ad13 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -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); /*