Commit 8922ba71 authored by Mårten Lindahl's avatar Mårten Lindahl Committed by Russell King (Oracle)
Browse files

ARM: 9317/1: kexec: Make smp stop calls asynchronous 



If a panic is triggered by a hrtimer interrupt all online cpus will be
notified and set offline. But as highlighted by commit 19dbdcb8
("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: default avatarMårten Lindahl <marten.lindahl@axis.com>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
parent e6b51532

arch/arm/kernel/machine_kexec.c

+13 −1
Original line number Diff line number Diff line
@@ -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);