| Message ID | 20221109014706.10484-1-zhouzhouyi@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [linux-next,RFC] powerpc: move pseries interrupt cleanup code to under __cpu_disable | expand |
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index e0a7ac5db15d..c7c86ea0a74d 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -62,12 +62,7 @@ static void pseries_cpu_offline_self(void) { unsigned int hwcpu = hard_smp_processor_id(); - local_irq_disable(); idle_task_exit(); - if (xive_enabled()) - xive_teardown_cpu(); - else - xics_teardown_cpu(); unregister_slb_shadow(hwcpu); rtas_stop_self(); @@ -96,3 +91,10 @@ static int pseries_cpu_disable(void) cleanup_cpu_mmu_context(); + local_irq_disable(); + + if (xive_enabled()) + xive_teardown_cpu(); + else + xics_teardown_cpu(); +
According to Link: https://lore.kernel.org/lkml/20220914021528.15946-1-zhouzhouyi@gmail.com/T/ Link: https://lore.kernel.org/lkml/CN6WCMKCWHOG.LT2QV3910UJ2@bobo/ During the cpu offlining, the sub functions of xive_teardown_cpu will call __lock_acquire when CONFIG_LOCKDEP=y. The latter function will travel RCU protected list, so "WARNING: suspicious RCU usage" will be triggered. According to Documentation/core-api/cpu_hotplug.rst: __cpu_disable should shut down the interrupt handler. This patch move pseries interrupt cleanup code to under __cpu_disable. RCU torture tested in ppc VM of Open Source Lab of Oregon State University, by comparing the test results, our fix don't introduce new bugs and fixed previous "WARNING: suspicious RCU usage" bugs. Suggested-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> --- Dear PPC and RCU developers I tries do move pseries interrupt cleanup code to under __cpu_disable. During this process, I learn the XIVE interrupt controller architecture by debugging the qemu virtual machine, and reading the following documents: Link: https://www.qemu.org/docs/master/specs/ppc-spapr-xive.html Link: https://www.qemu.org/docs/master/specs/ppc-xive.html It is a fruitful journey, thank you for you guidance ;-) I also tested the patch in ppc VM of Open Source Lab of Oregon State University by invoking tools/testing/selftests/rcutorture/bin/torture.sh Thanks again Zhouyi -- arch/powerpc/platforms/pseries/hotplug-cpu.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) return 0; }