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.

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           | 15 ++++++++-------
 arch/powerpc/perf/core-fsl-emb.c       |  3 ++-
 arch/powerpc/platforms/powernv/setup.c |  2 +-
 3 files changed, 11 insertions(+), 9 deletions(-)

-- 
2.54.0

Hi Aboorva,

On 5/18/26 10:38 AM, Aboorva Devarajan wrote:
> 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.
> 

Thanks for fixing some of these.

while we do this, Can you fix these mismatch in preempt disable/enable in
below files as well.

1. kernel/kprobes.c - kprobe_handler - Does disable, but doesn't enable in some return paths.
    A definite leak.

2. Maybe platforms/pseries/lpar.c and platforms/powernv/opal-tracepoints.c.
    In __trace_hcall_entry/exit.  It maybe a very corner case,
    I don't see a big concern there. But it may be remotely possible.
    Need to evaluate whether it should be fixed or not.