From 0ecd26e93e698c8327521910fc6296f5b84a4b92 Mon Sep 17 00:00:00 2001 From: Aboorva Devarajan Date: Fri, 5 Jun 2026 13:59:11 +0530 Subject: [PATCH] powerpc/powernv: fix preempt count leak in pnv_kexec_wait_secondaries_down pnv_kexec_wait_secondaries_down() calls get_cpu() to obtain the current CPU id but never calls the matching put_cpu(), leaking one preempt_disable() nesting level on every invocation. In practice the imbalance does not trigger a visible splat because the kexec teardown path is a one-way trip: IRQs are already disabled, no schedule() occurs after the leak, and default_machine_kexec() overwrites preempt_count with HARDIRQ_OFFSET before jumping into kexec_sequence() which never returns. However the bookkeeping is still wrong. The function only needs the current CPU id, and this path runs with interrupts disabled and the CPU pinned, so the preempt_disable() side-effect of get_cpu() is unnecessary. Replace it with raw_smp_processor_id(). Fixes: 298b34d7d578 ("powerpc/powernv: Fix kexec races going back to OPAL") Signed-off-by: Aboorva Devarajan Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260605082912.305100-3-aboorvad@linux.ibm.com --- arch/powerpc/platforms/powernv/setup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c index 4dbb47ddbdcc..06ed5e2aa265 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -396,7 +396,8 @@ static void pnv_kexec_wait_secondaries_down(void) { int my_cpu, i, notified = -1; - my_cpu = get_cpu(); + /* Called with interrupts disabled, so the CPU is pinned. */ + my_cpu = raw_smp_processor_id(); for_each_online_cpu(i) { uint8_t status;