Messages in this thread Patch in this message | | | From | Mårten Lindahl <> | Date | Mon, 7 Aug 2023 15:34:50 +0200 | Subject | [PATCH v2] ARM: kexec: Make smp stop calls asynchronous |
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If a panic is triggered by a hrtimer interrupt all online cpus will be notified and set offline. But as highlighted by commit 19dbdcb8039c ("smp: Warn on function calls from softirq context") this call should not be made synchronous with disabled interrupts:
softdog: Initiating panic Kernel panic - not syncing: Software Watchdog Timer expired WARNING: CPU: 1 PID: 0 at kernel/smp.c:753 smp_call_function_many_cond unwind_backtrace: show_stack dump_stack_lvl __warn warn_slowpath_fmt smp_call_function_many_cond smp_call_function crash_smp_send_stop.part.0 machine_crash_shutdown __crash_kexec panic softdog_fire __hrtimer_run_queues hrtimer_interrupt
Make the smp call for machine_crash_nonpanic_core() asynchronous.
Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com> --- Changes in v2: - Fixed commit msg typo "noitfied" => "notified" - Link to v1: https://lore.kernel.org/r/20230615-arm-smp-call-async-v1-1-58f4afb20f0f@axis.com --- arch/arm/kernel/machine_kexec.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index 46364b699cc3..5d07cf9e0044 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -94,16 +94,28 @@ static void machine_crash_nonpanic_core(void *unused) } } +static DEFINE_PER_CPU(call_single_data_t, cpu_stop_csd) = + CSD_INIT(machine_crash_nonpanic_core, NULL); + void crash_smp_send_stop(void) { static int cpus_stopped; unsigned long msecs; + call_single_data_t *csd; + int cpu, this_cpu = raw_smp_processor_id(); if (cpus_stopped) return; atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); - smp_call_function(machine_crash_nonpanic_core, NULL, false); + for_each_online_cpu(cpu) { + if (cpu == this_cpu) + continue; + + csd = &per_cpu(cpu_stop_csd, cpu); + smp_call_function_single_async(cpu, csd); + } + msecs = 1000; /* Wait at most a second for the other cpus to stop */ while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { mdelay(1); --- base-commit: 52a93d39b17dc7eb98b6aa3edb93943248e03b2f change-id: 20230807-arm-smp-call-async-4c1da2de9621 Best regards, -- Mårten Lindahl <marten.lindahl@axis.com>
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