8945c49915
There may be multiple invocations of kernel_restart simultaneously. Change reboot_timeout timer to schedule only if it is inactive. Also add spinlock to protect against concurrent timer access. Bug: 156425203 Bug: 168751003 Bug: 186741894 Change-Id: I4941aa032510dad7c6f4e79eda39be05827d7b04 Signed-off-by: Jonglin Lee <jonglin@google.com> (cherry picked from commit 45907eef19e782a8a53fc32282ef61bac8877329)
157 lines
3.8 KiB
C
157 lines
3.8 KiB
C
/*
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* drivers/power/reset/debug-reboot.c
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*
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* Utility module to test various debug reboot types.
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*
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* Copyright (C) 2019 Google, Inc.
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/reboot.h>
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#include <linux/time.h>
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#include <linux/sched/debug.h>
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#define PANIC_REBOOT_CMD "debug-reboot-panic"
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#define WDOG_REBOOT_CMD "debug-reboot-watchdog"
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#define HANG_REBOOT_CMD "debug-reboot-hang"
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#define REBOOT_TIMER_TIMEOUT_MS 15000
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static struct timer_list reboot_timer;
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static DEFINE_SPINLOCK(timer_lock);
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#ifdef CONFIG_DEBUG_REBOOT_DEFAULT_ON
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static bool enable = 1;
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#else
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static bool enable;
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#endif
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module_param(enable, bool, 0644);
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MODULE_PARM_DESC(enable, "Enable/disable debug reboot commands");
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static bool stop_cpus = 1;
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module_param(stop_cpus, bool, 0644);
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MODULE_PARM_DESC(stop_cpus, "Stop other cpus during watchdog (default: Y)");
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static void debug_reboot_panic(void)
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{
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char *pointer = NULL;
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pr_info("debug-reboot: Trigger a panic\n");
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/* Trigger a NULL pointer dereference */
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*pointer = 'a';
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/* Should not reach here */
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pr_err("debug-reboot: Trigger panic failed!\n");
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}
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static void debug_reboot_hang(void)
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{
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pr_info("debug-reboot: Hogging a CPU now\n");
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for(;;)
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;
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/* Should not reach here */
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pr_err("debug-reboot: Simulate reboot hang fail !\n");
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}
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static void debug_reboot_watchdog(void)
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{
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pr_info("debug-reboot: Trigger a watchdog\n");
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if (stop_cpus) {
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/* Stop other CPUs to ensure only this core running */
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smp_send_stop();
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}
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/* Disable interrupts and loop forever */
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local_irq_disable();
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debug_reboot_hang();
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/* Should not reach here */
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pr_err("debug-reboot: Trigger watchdog failed!\n");
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}
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static void reboot_timeout(struct timer_list *t)
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{
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pr_info("debug-reboot: Reboot timer (%d seconds) timeout - Show All Blocked State\n"
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, (REBOOT_TIMER_TIMEOUT_MS/1000));
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show_state_filter(TASK_UNINTERRUPTIBLE);
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debug_reboot_panic();
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}
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static void add_reboot_timer(void)
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{
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unsigned long flags;
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pr_info("debug-reboot: Create reboot monitor timer now\n");
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spin_lock_irqsave(&timer_lock, flags);
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if (!timer_pending(&reboot_timer)) {
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reboot_timer.expires =
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jiffies + msecs_to_jiffies(REBOOT_TIMER_TIMEOUT_MS);
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add_timer(&reboot_timer);
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}
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spin_unlock_irqrestore(&timer_lock, flags);
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}
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static int debug_reboot_notify(struct notifier_block *nb,
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unsigned long code, void *cmd)
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{
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/*add a timer to monitor reboot or shutdown process.*/
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add_reboot_timer();
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if (enable && code == SYS_RESTART) {
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if (cmd != NULL) {
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if (!strcmp((char *)cmd, PANIC_REBOOT_CMD)) {
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debug_reboot_panic();
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/* Should not return... */
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} else if (!strcmp((char *)cmd, WDOG_REBOOT_CMD)) {
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debug_reboot_watchdog();
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/* Should not return... */
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} else if (!strcmp((char *)cmd, HANG_REBOOT_CMD)) {
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debug_reboot_hang();
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/* Should not return... */
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}
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}
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block debug_reboot_nb = {
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.notifier_call = debug_reboot_notify,
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.priority = INT_MAX,
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};
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static int __init debug_reboot_init(void)
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{
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timer_setup(&reboot_timer, reboot_timeout, 0);
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return register_reboot_notifier(&debug_reboot_nb);
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}
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static void __exit debug_reboot_exit(void)
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{
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unregister_reboot_notifier(&debug_reboot_nb);
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del_timer_sync(&reboot_timer);
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}
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module_init(debug_reboot_init);
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module_exit(debug_reboot_exit);
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MODULE_DESCRIPTION("Module for testing debug reboots");
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MODULE_AUTHOR("Jonglin Lee <jonglin@google.com>");
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MODULE_LICENSE("GPL v2");
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