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.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Guilherme G . Piccoli" <gpiccoli@canonical.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200427180433.7029-4-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d02b9d0..0c72b5c 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/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

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 1242981..1503078 100644 (file)
--- a/fs/proc/proc_sysctl.c
+++ b/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" },
        { }
 };
 

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 14a625c..b22b5ee 100644 (file)
--- a/kernel/hung_task.c
+++ b/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)
 {