5.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Nicholas Piggin <[email protected]> commit 1b5fc84aba170bdfe3533396ca9662ceea1609b7 upstream. 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: 5b73151fff63 ("powerpc: NMI IPI make NMI IPIs fully sychronous") Cc: [email protected] # v4.19+ Signed-off-by: Nicholas Piggin <[email protected]> Signed-off-by: Michael Ellerman <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/powerpc/kernel/smp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -519,7 +519,7 @@ int __smp_send_nmi_ipi(int cpu, void (*f if (delay_us) { delay_us--; if (!delay_us) - break; + goto timeout; } } @@ -530,10 +530,11 @@ int __smp_send_nmi_ipi(int cpu, void (*f 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;
