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Nicholas Piggin authored
smp_send_stop can lock up the IPI path for any subsequent calls, because the receiving CPUs spin in their handler function. This started becoming a problem with the addition of an smp_send_stop call in the reboot path, because panics can reboot after doing their own smp_send_stop. The NMI IPI variant was fixed with ac61c115 ("powerpc: Fix smp_send_stop NMI IPI handling"), which leaves the smp_call_function variant. This is fixed by having smp_send_stop only ever do the smp_call_function once. This is a bit less robust than the NMI IPI fix, because any other call to smp_call_function after smp_send_stop could deadlock, but that has always been the case, and it was not been a problem before. Fixes: f2748bdf ("powerpc/powernv: Always stop secondaries before reboot/shutdown") Reported-by:
Abdul Haleem <abdhalee@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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