Hi all, This patch series fixes some minor preempt_count bookkeeping issues in arch/powerpc/ found during a preemption leak audit prompted by the lazy/full preemption model changes. These are get_cpu/put_cpu and get_cpu_var/put_cpu_var pairing errors that leave preempt_count incorrectly elevated or underflowed.
v1: https://lore.kernel.org/all/[email protected]/ v1 -> v2: - Patch 1 (fsl_emb_pmu_del): no functional change; picked up Shrikanth's Reviewed-by. - Patch 2 (pnv_kexec_wait_secondaries_down): per Shrikanth's review, use smp_processor_id() instead of raw_smp_processor_id(). The kexec/ crash teardown path runs with IRQs disabled so it is safe. - Patch 3 (kexec_prepare_cpus): per Shrikanth's review, dropped the approach of passing the cpu id through kexec_prepare_cpus_wait() as a parameter. kexec_prepare_cpus() already runs local_irq_disable()/ hard_irq_disable() before the wait, so get_cpu()/put_cpu() is unnecessary: just read the cpu id in kexec_prepare_cpus_wait() and drop the trailing put_cpu(). This keeps the function signature unchanged. smp_processor_id() is used here too, consistent with patch 2. Testing: - Patch 1: compile-tested only (ppc64e_defconfig + CONFIG_FSL_EMB_PERFMON); no e500/fsl_emb hardware to runtime-test so far. - Patches 2 and 3: kexec boot-tested on PowerNV (powernv_defconfig) and pseries (pseries_defconfig). Please let me know your comments. Thanks, Aboorva Aboorva Devarajan (3): powerpc/perf: fix preempt count underflow in fsl_emb_pmu_del powerpc/powernv: fix preempt count leak in pnv_kexec_wait_secondaries_down powerpc/kexec: fix double get_cpu() imbalance in kexec_prepare_cpus arch/powerpc/kexec/core_64.c | 4 +--- arch/powerpc/perf/core-fsl-emb.c | 3 ++- arch/powerpc/platforms/powernv/setup.c | 2 +- 3 files changed, 4 insertions(+), 5 deletions(-) -- 2.54.0
