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8bb763d4c3
Add a new "dump" pretimeout governor that triggers a backtrace of all CPUs (via trigger_all_cpu_backtrace()) to the kernel log buffer. This provides diagnostic information right before the hardware watchdog fires. In addition, update the WATCHDOG_PRETIMEOUT_GOV_SEL Kconfig logic to fall back to the "panic" governor only when both "noop" and "dump" governors are disabled. Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org> Link: https://lore.kernel.org/r/20260707102105.3600275-1-tzungbi@kernel.org Signed-off-by: Guenter Roeck <linux@roeck-us.net>
46 lines
1.1 KiB
C
46 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2026 Google LLC
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/nmi.h>
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#include <linux/watchdog.h>
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#include "watchdog_pretimeout.h"
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/**
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* pretimeout_dump - Dump on watchdog pretimeout event
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* @wdd: watchdog_device
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*
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* Dump all cpu backtrace on pretimeout event.
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*/
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static void pretimeout_dump(struct watchdog_device *wdd)
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{
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pr_alert("watchdog%d: pretimeout event\n", wdd->id);
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if (!trigger_all_cpu_backtrace())
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pr_alert("trigger_all_cpu_backtrace() isn't available\n");
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}
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static struct watchdog_governor watchdog_gov_dump = {
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.name = "dump",
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.pretimeout = pretimeout_dump,
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};
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static int __init watchdog_gov_dump_register(void)
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{
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return watchdog_register_governor(&watchdog_gov_dump);
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}
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static void __exit watchdog_gov_dump_unregister(void)
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{
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watchdog_unregister_governor(&watchdog_gov_dump);
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}
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module_init(watchdog_gov_dump_register);
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module_exit(watchdog_gov_dump_unregister);
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MODULE_AUTHOR("Tzung-Bi Shih <tzungbi@kernel.org>");
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MODULE_DESCRIPTION("Dump watchdog pretimeout governor");
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MODULE_LICENSE("GPL");
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