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Commit 377c09d7 authored by Patrick Fay's avatar Patrick Fay
Browse files

perf: Fix NULL pointer ref in exclude_idle update 



Commit 573979de ("perf: Add support for exclude_idle attribute")
registers an idle callback routine armv8pmu_idle_update. Currently
the idle update routine might be called before the pmu has allocated
all the per_cpu structures. This can result in a null pointer
reference. Change arm_pmu_device_probe to allocate the structures
via cpu_pmu_init() before the init_fn() call (which eventually does the
idle_notify_register call). Change a branch to out_free to
out_destroy as out_free doesn't cleanup what was allocated in
cpu_pmu_init(). Also have armv8pmu_idle_update check that the
structure is not null before using it.

Change-Id: Ie1198fc1783804c61467889c68656d6e8c9c9edf
Signed-off-by: default avatarPatrick Fay <pfay@codeaurora.org>
parent 573979de

arch/arm64/kernel/perf_event.c

+3 −0
Original line number Diff line number Diff line
@@ -590,6 +590,9 @@ static void armv8pmu_idle_update(struct arm_pmu *cpu_pmu) 


	hw_events = this_cpu_ptr(cpu_pmu->hw_events);



	if (!hw_events)

		return;



	for (idx = 0; idx < cpu_pmu->num_events; ++idx) {



		if (!test_bit(idx, hw_events->used_mask))

drivers/perf/arm_pmu.c

+5 −5
Original line number Diff line number Diff line
@@ -1051,6 +1051,10 @@ int arm_pmu_device_probe(struct platform_device *pdev, 


	pmu->plat_device = pdev;



	ret = cpu_pmu_init(pmu);

	if (ret)

		goto out_free;



	if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {

		init_fn = of_id->data;
@@ -1073,13 +1077,9 @@ int arm_pmu_device_probe(struct platform_device *pdev, 


	if (ret) {

		pr_info("%s: failed to probe PMU!\n", of_node_full_name(node));

		goto out_free;

		goto out_destroy;

	}



	ret = cpu_pmu_init(pmu);

	if (ret)

		goto out_free;



	ret = perf_pmu_register(&pmu->pmu, pmu->name, -1);

	if (ret)

		goto out_destroy;