[09/54] kernel/hung_task convert hung_task_panic boot parameter to sysctl

Commit Message

Andrew Morton June 8, 2020, 4:40 a.m. UTC

From: Vlastimil Babka <[e-mail]>
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/[e-mail]
Signed-off-by: Vlastimil Babka <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Acked-by: Michal Hocko <[e-mail]>
Cc: Alexey Dobriyan <[e-mail]>
Cc: Christian Brauner <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: "Eric W . Biederman" <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: "Guilherme G . Piccoli" <[e-mail]>
Cc: Iurii Zaikin <[e-mail]>
Cc: Ivan Teterevkov <[e-mail]>
Cc: Luis Chamberlain <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 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(-)

Patch

--- 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)
 {