drivers/perf: arm_pmu: Defer the setting of __oprofile_cpu_pmu

commit 0f254c7671e851243412bce6c2e618732831d0f8 upstream.

The global variable __oprofile_cpu_pmu is set before the PMU is fully
initialized. If an error occurs before the end of the initialization,
the PMU will be freed and the variable will contain an invalid pointer.

This will result in a kernel crash when perf will be used.

Fix it by moving the setting of __oprofile_cpu_pmu when the PMU is fully
initialized (i.e when it is no longer possible to fail).

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index f70090897fdf19c9777c332401dd01de7b1efc52..0e537fdc1d086d76f1fd709631844930448a824b 100644 (file)
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -987,9 +987,6 @@ int arm_pmu_device_probe(struct platform_device *pdev,
 
        armpmu_init(pmu);
 
-       if (!__oprofile_cpu_pmu)
-               __oprofile_cpu_pmu = pmu;
-
        pmu->plat_device = pdev;
 
        if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
@@ -1025,6 +1022,9 @@ int arm_pmu_device_probe(struct platform_device *pdev,
        if (ret)
                goto out_destroy;
 
+       if (!__oprofile_cpu_pmu)
+               __oprofile_cpu_pmu = pmu;
+
        pr_info("enabled with %s PMU driver, %d counters available\n",
                        pmu->name, pmu->num_events);