Re: latest -git: WARNING: at arch/x86/kernel/ipi.c:123 send_IPI_mask_bitmask+0xc3/0xe0()

H. Peter Anvin
2008-08-24T17:17:44Z

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Vegard Nossum wrote:
>
> Hm.
>
> Kernel fails to detect cpu1 at all.
>
> I am currently unsure of whether it's your patch or not. But it's the
> same config that I've been booting for ages (and I copy it over for
> each new kernel version I check out).
>
> Processor #0 (Bootup-CPU)
> I/O APIC #2 Version 32 at 0xFEC00000.
> Enabling APIC mode: Flat. Using 1 I/O APICs
> Processors: 1
> SMP: Allowing 1 CPUs, 0 hotplug CPUs
> mapped APIC to ffffb000 (fee00000)
> mapped IOAPIC to ffffa000 (fec00000)
> Allocating PCI resources starting at 50000000 (gap: 40000000:bee00000)
> PERCPU: Allocating 1221764 bytes of per cpu data
> NR_CPUS: 7, nr_cpu_ids: 1, nr_node_ids 1
>
> I really don't get it. Is this something that can be caused by your
> patch _at all_ ?
>

Could you try this patch? It should (hopefully) tell us if there is any
such invocations and what the call trace looks like.

-hpa

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diff --git a/kernel/smp.c b/kernel/smp.c
index 782e2b9..95e1bad 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -210,8 +210,10 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
{
struct call_single_data d;
unsigned long flags;
- /* prevent preemption and reschedule on another processor */
+ /* prevent preemption and reschedule on another processor,
+ as well as CPU removal */
int me = get_cpu();
+ int err = 0;

/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
@@ -220,7 +222,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
local_irq_save(flags);
func(info);
local_irq_restore(flags);
- } else {
+ } else if ((unsigned)cpu < NR_CPUS && cpu_online(cpu)) {
struct call_single_data *data = NULL;

if (!wait) {
@@ -236,10 +238,13 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
data->func = func;
data->info = info;
generic_exec_single(cpu, data);
+ } else {
+ BUG();
+ err = -ENXIO; /* CPU not online */
}

put_cpu();
- return 0;
+ return err;
}
EXPORT_SYMBOL(smp_call_function_single);