hung_task: Change sysctl_hung_task_check_count to 'int' (cd64647f) · Commits · 戴 / test

As 'sysctl_hung_task_check_count' is 'unsigned long' when this value is assigned to max_count in check_hung_uninterruptible_tasks(), it's truncated to 'int' type. This causes a minor artifact: if we write 2^32 to sysctl.hung_task_check_count, hung task detection will be effectively disabled. With this fix, it will still truncate the user input to 32 bits, but reading sysctl.hung_task_check_count reflects the actual truncated value. Signed-off-by:

Li Zefan <lizefan@huawei.com> Acked-by:

Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/523FFF4E.9050401@huawei.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/linux/sched/sysctl.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -2,8 +2,8 @@
		#define _SCHED_SYSCTL_H

		#ifdef CONFIG_DETECT_HUNG_TASK
		extern int sysctl_hung_task_check_count;
		extern unsigned int sysctl_hung_task_panic;
		extern unsigned long sysctl_hung_task_check_count;
		extern unsigned long sysctl_hung_task_timeout_secs;
		extern unsigned long sysctl_hung_task_warnings;
		extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,

kernel/hung_task.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -20,7 +20,7 @@
		/*
		* The number of tasks checked:
		*/
		unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
		int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;

		/*
		* Limit number of tasks checked in a batch.

kernel/sysctl.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -962,9 +962,10 @@ static struct ctl_table kern_table[] = {
		{
		.procname = "hung_task_check_count",
		.data = &sysctl_hung_task_check_count,
		.maxlen = sizeof(unsigned long),
		.maxlen = sizeof(int),
		.mode = 0644,
		.proc_handler = proc_doulongvec_minmax,
		.proc_handler = proc_dointvec_minmax,
		.extra1 = &zero,
		},
		{
		.procname = "hung_task_timeout_secs",

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