From: Yufen Wang <wangyu...@huawei.com>
In case panic() and panic() called at the same time on different CPUS.
For example:
CPU 0:
panic()
__crash_kexec
machine_crash_shutdown
crash_smp_send_stop
machine_kexec
BUG_ON(num_online_cpus() > 1);
CPU 1:
panic()
local_irq_disable
panic_smp_self_stop
If CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop(), kdump
fails. CPU1 can't receive the ipi irq, CPU1 will be always online.
I changed BUG_ON to WARN in kexec crash as arm64 does, kdump also fails.
Because num_online_cpus() > 1, can't disable the L2 in _soft_restart.
To fix this problem, this patch split out the panic_smp_self_stop()
and add set_cpu_online(smp_processor_id(), false).
Signed-off-by: Yufen Wang <wangyu...@huawei.com>
---
arch/arm/kernel/setup.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 31940bd..151861f 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -602,6 +602,16 @@ static void __init smp_build_mpidr_hash(void)
}
#endif
+void panic_smp_self_stop(void)
+{
+ printk(KERN_DEBUG "CPU %u will stop doing anything useful since another
CPU has paniced\n",
+ smp_processor_id());
+ set_cpu_online(smp_processor_id(), false);
+ while (1)
+ cpu_relax();
+
+}
+
static void __init setup_processor(void)
{
struct proc_info_list *list;
--
2.7.4
