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-rw-r--r--arch/powerpc/kernel/stacktrace.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index 1961e6d5e33b..2b0d04a1b7d2 100644
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -172,17 +172,31 @@ static void handle_backtrace_ipi(struct pt_regs *regs)
static void raise_backtrace_ipi(cpumask_t *mask)
{
+ struct paca_struct *p;
unsigned int cpu;
+ u64 delay_us;
for_each_cpu(cpu, mask) {
- if (cpu == smp_processor_id())
+ if (cpu == smp_processor_id()) {
handle_backtrace_ipi(NULL);
- else
- smp_send_safe_nmi_ipi(cpu, handle_backtrace_ipi, 5 * USEC_PER_SEC);
- }
+ continue;
+ }
- for_each_cpu(cpu, mask) {
- struct paca_struct *p = paca_ptrs[cpu];
+ delay_us = 5 * USEC_PER_SEC;
+
+ if (smp_send_safe_nmi_ipi(cpu, handle_backtrace_ipi, delay_us)) {
+ // Now wait up to 5s for the other CPU to do its backtrace
+ while (cpumask_test_cpu(cpu, mask) && delay_us) {
+ udelay(1);
+ delay_us--;
+ }
+
+ // Other CPU cleared itself from the mask
+ if (delay_us)
+ continue;
+ }
+
+ p = paca_ptrs[cpu];
cpumask_clear_cpu(cpu, mask);