On 5/18/26 10:38 AM, Aboorva Devarajan wrote:
fsl_emb_pmu_del() unconditionally calls put_cpu_var(cpu_hw_events) at the 'out:' label, but only calls the matching get_cpu_var() after the 'i < 0' early-return check. When event->hw.idx is negative the function jumps to 'out:' without having taken get_cpu_var(), and the trailing put_cpu_var() then issues an unmatched preempt_enable(), underflowing preempt_count. On a CONFIG_PREEMPT=y kernel preempt_count would underflow and eventually present as a 'scheduling while atomic' BUG. Move put_cpu_var() to pair with get_cpu_var() so the percpu access is correctly bracketed and the 'out:' label only handles perf_pmu_enable. Fixes: a11106544f33c ("powerpc/perf: e500 support") Signed-off-by: Aboorva Devarajan <[email protected]> --- arch/powerpc/perf/core-fsl-emb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/perf/core-fsl-emb.c b/arch/powerpc/perf/core-fsl-emb.c index 7120ab20cbfec..02b5dd74c187a 100644 --- a/arch/powerpc/perf/core-fsl-emb.c +++ b/arch/powerpc/perf/core-fsl-emb.c @@ -366,9 +366,10 @@ static void fsl_emb_pmu_del(struct perf_event *event, int flags)cpuhw->n_events--; + put_cpu_var(cpu_hw_events);+ out: perf_pmu_enable(event->pmu); - put_cpu_var(cpu_hw_events); }static void fsl_emb_pmu_start(struct perf_event *event, int ef_flags)
Thanks for fixing this. Looks good to me. Reviewed-by: Shrikanth Hegde <[email protected]>
