Commit aeef84f3 authored by Yufen Wang's avatar Yufen Wang Committed by Greg Kroah-Hartman

ARM: 8808/1: kexec:offline panic_smp_self_stop CPU

[ Upstream commit 82c08c3e7f171aa7f579b231d0abbc1d62e91974 ]

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.
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: 's avatarYufen Wang <wangyufen@huawei.com>
Signed-off-by: 's avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: 's avatarSasha Levin <sashal@kernel.org>
parent 871243fc
......@@ -687,6 +687,21 @@ void smp_send_stop(void)
pr_warn("SMP: failed to stop secondary CPUs\n");
}
/* In case panic() and panic() called at the same time on CPU1 and CPU2,
* and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
* CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
* kdump fails. So split out the panic_smp_self_stop() and add
* set_cpu_online(smp_processor_id(), false).
*/
void panic_smp_self_stop(void)
{
pr_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();
}
/*
* not supported here
*/
......
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