From: Vlastimil Babka <vbabka@xxxxxxx> Subject: kernel/hung_task convert hung_task_panic boot parameter to sysctl We can now handle sysctl parameters on kernel command line and have infrastructure to convert legacy command line options that duplicate sysctl to become a sysctl alias. This patch converts the hung_task_panic parameter. Note that the sysctl handler is more strict and allows only 0 and 1, while the legacy parameter allowed any non-zero value. But there is little reason anyone would not be using 1. Link: http://lkml.kernel.org/r/20200427180433.7029-4-vbabka@xxxxxxx Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Christian Brauner <christian.brauner@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: "Eric W . Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Guilherme G . Piccoli" <gpiccoli@xxxxxxxxxxxxx> Cc: Iurii Zaikin <yzaikin@xxxxxxxxxx> Cc: Ivan Teterevkov <ivan.teterevkov@xxxxxxxxxxx> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/admin-guide/kernel-parameters.txt | 2 +- fs/proc/proc_sysctl.c | 1 + kernel/hung_task.c | 10 ---------- 3 files changed, 2 insertions(+), 11 deletions(-) --- a/Documentation/admin-guide/kernel-parameters.txt~kernel-hung_task-convert-hung_task_panic-boot-parameter-to-sysctl +++ a/Documentation/admin-guide/kernel-parameters.txt @@ -1515,7 +1515,7 @@ [KNL] Should the hung task detector generate panics. Format: <integer> - A nonzero value instructs the kernel to panic when a + A value of 1 instructs the kernel to panic when a hung task is detected. The default value is controlled by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value selected by this boot parameter can --- a/fs/proc/proc_sysctl.c~kernel-hung_task-convert-hung_task_panic-boot-parameter-to-sysctl +++ a/fs/proc/proc_sysctl.c @@ -1721,6 +1721,7 @@ struct sysctl_alias { */ static const struct sysctl_alias sysctl_aliases[] = { {"numa_zonelist_order", "vm.numa_zonelist_order" }, + {"hung_task_panic", "kernel.hung_task_panic" }, { } }; --- a/kernel/hung_task.c~kernel-hung_task-convert-hung_task_panic-boot-parameter-to-sysctl +++ a/kernel/hung_task.c @@ -63,16 +63,6 @@ static struct task_struct *watchdog_task unsigned int __read_mostly sysctl_hung_task_panic = CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE; -static int __init hung_task_panic_setup(char *str) -{ - int rc = kstrtouint(str, 0, &sysctl_hung_task_panic); - - if (rc) - return rc; - return 1; -} -__setup("hung_task_panic=", hung_task_panic_setup); - static int hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr) { _
