From: Sangmoon Kim Date: Tue, 6 Aug 2024 05:12:09 +0000 (+0900) Subject: workqueue: add cmdline parameter workqueue.panic_on_stall X-Git-Tag: v6.12-rc1~167^2~9 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=073107b39e553a5ef911f019d4e433fd5a8601b7;p=linux-block.git workqueue: add cmdline parameter workqueue.panic_on_stall When we want to debug the workqueue stall, we can immediately make a panic to get the information we want. In some systems, it may be necessary to quickly reboot the system to escape from a workqueue lockup situation. In this case, we can control the number of stall detections to generate panic. workqueue.panic_on_stall sets the number times of the stall to trigger panic. 0 disables the panic on stall. Signed-off-by: Sangmoon Kim Signed-off-by: Tejun Heo --- diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1745ca788ede..80cb0a923046 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -7398,6 +7398,9 @@ static struct timer_list wq_watchdog_timer; static unsigned long wq_watchdog_touched = INITIAL_JIFFIES; static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES; +static unsigned int wq_panic_on_stall; +module_param_named(panic_on_stall, wq_panic_on_stall, uint, 0644); + /* * Show workers that might prevent the processing of pending work items. * The only candidates are CPU-bound workers in the running state. @@ -7449,6 +7452,16 @@ static void show_cpu_pools_hogs(void) rcu_read_unlock(); } +static void panic_on_wq_watchdog(void) +{ + static unsigned int wq_stall; + + if (wq_panic_on_stall) { + wq_stall++; + BUG_ON(wq_stall >= wq_panic_on_stall); + } +} + static void wq_watchdog_reset_touched(void) { int cpu; @@ -7521,6 +7534,9 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) if (cpu_pool_stall) show_cpu_pools_hogs(); + if (lockup_detected) + panic_on_wq_watchdog(); + wq_watchdog_reset_touched(); mod_timer(&wq_watchdog_timer, jiffies + thresh); }