drivers: perf: Fix wrong put_cpu() placement

Unfortunately, the wrong patch version was merged which places the
put_cpu() after enabling a static key, which is not safe as pointed by
Will [1], so move put_cpu() before to avoid this.

Fixes: 2840dadf0dde ("drivers: perf: Fix smp_processor_id() use in preemptible code")
Reported-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/all/20240827125335.GD4772@willie-the-truck/
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241112113422.617954-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 391ca1422caec15b69b747bc8bcaef3c9faead23..1aa303f76cc7afc3949a2bcee26821034b4e80de 100644 (file)
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1393,8 +1393,9 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
                        goto out_unregister;
 
                cpu = get_cpu();
-
                ret = pmu_sbi_snapshot_setup(pmu, cpu);
+               put_cpu();
+
                if (ret) {
                        /* Snapshot is an optional feature. Continue if not available */
                        pmu_sbi_snapshot_free(pmu);
@@ -1408,7 +1409,6 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
                         */
                        static_branch_enable(&sbi_pmu_snapshot_available);
                }
-               put_cpu();
        }
 
        register_sysctl("kernel", sbi_pmu_sysctl_table);