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powerpc/smp: Fix NMI IPI timeout 

The NMI IPI timeout logic is broken, if __smp_send_nmi_ipi() times out
on the first condition, delay_us will be zero which will send it into
the second spin loop with no timeout so it will spin forever.

Fixes: 5b73151fff ("powerpc: NMI IPI make NMI IPIs fully sychronous")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2018-11-26 12:01:05 +10:00 committed by Michael Ellerman
parent bba436309d
commit 1b5fc84aba
1 changed files with 3 additions and 2 deletions
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5
arch/powerpc/kernel/smp.c
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@ -519,7 +519,7 @@ int __smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us, bool
if (delay_us) {
delay_us--;
if (!delay_us)
break;
goto timeout;
}
}
@ -530,10 +530,11 @@ int __smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us, bool
if (delay_us) {
delay_us--;
if (!delay_us)
break;
goto timeout;
}
}
timeout:
if (!cpumask_empty(&nmi_ipi_pending_mask)) {
/* Timeout waiting for CPUs to call smp_handle_nmi_ipi */
ret = 0;