evie/android_kernel_oneplus_msm8998
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perf: Fix NULL pointer ref in exclude_idle update

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Commit 573979dee2 ("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: Patrick Fay <pfay@codeaurora.org>
This commit is contained in:
Patrick Fay 2016-11-03 17:07:16 -07:00
parent 573979dee2
commit 377c09d738
2 changed files with 8 additions and 5 deletions
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3
arch/arm64/kernel/perf_event.c
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@ -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))

10
drivers/perf/arm_pmu.c
View file

@ -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;