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| author |   Nicholas Piggin <npiggin@gmail.com> | 2018-04-27 11:51:59 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2018-04-27 16:35:57 +1000 |
| commit | 6029755eed95e5c90f763188c87ae3ff41e48e5c (patch) | |
| tree | 912e2106089759f15a24f1e2f5bf384946c42878 /arch/powerpc/kvm/booke.c | |
| parent | cpufreq: powernv: Fix hardlockup due to synchronous smp_call in timer interrupt (diff) | |
| download | linux-dev-6029755eed95e5c90f763188c87ae3ff41e48e5c.tar.xz linux-dev-6029755eed95e5c90f763188c87ae3ff41e48e5c.zip | |
powerpc: Fix deadlock with multiple calls to smp_send_stop
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 ac61c11566 ("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: f2748bdfe1573 ("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>
Diffstat (limited to 'arch/powerpc/kvm/booke.c')
0 files changed, 0 insertions, 0 deletions