[bug report] perf: xgene: Add APM X-Gene SoC Performance Monitoring Unit driver

[Tai Tri Nguyen]

Hi Dan,

Thanks for reporting the bug.

On Tue, Jul 11, 2017 at 4:43 AM, Dan Carpenter <dan.carpenter at oracle.com> wrote:
> Hello Tai Nguyen,
>
> The patch 832c927d119b: "perf: xgene: Add APM X-Gene SoC Performance
> Monitoring Unit driver" from Jul 15, 2016, leads to the following
> static checker warning:
>
>         drivers/perf/xgene_pmu.c:1922 xgene_pmu_probe()
>         warn: 'xgene_pmu->pcppmu_csr' is an error pointer or valid
>
> drivers/perf/xgene_pmu.c
>   1851          if (version < 0)
>   1852                  return -ENODEV;
>                         ^^^^^^^^^^^^^^
> Good.  Direct returns are the way to go if possible.
>
>   1853
>   1854          if (version == PCP_PMU_V3)
>   1855                  xgene_pmu->ops = &xgene_pmu_v3_ops;
>   1856          else
>   1857                  xgene_pmu->ops = &xgene_pmu_ops;
>   1858
>   1859          INIT_LIST_HEAD(&xgene_pmu->l3cpmus);
>   1860          INIT_LIST_HEAD(&xgene_pmu->iobpmus);
>   1861          INIT_LIST_HEAD(&xgene_pmu->mcbpmus);
>   1862          INIT_LIST_HEAD(&xgene_pmu->mcpmus);
>   1863
>   1864          xgene_pmu->version = version;
>   1865          dev_info(&pdev->dev, "X-Gene PMU version %d\n", xgene_pmu->version);
>   1866
>   1867          res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   1868          xgene_pmu->pcppmu_csr = devm_ioremap_resource(&pdev->dev, res);
>   1869          if (IS_ERR(xgene_pmu->pcppmu_csr)) {
>   1870                  dev_err(&pdev->dev, "ioremap failed for PCP PMU resource\n");
>   1871                  rc = PTR_ERR(xgene_pmu->pcppmu_csr);
>   1872                  goto err;
>                         ^^^^^^^^
> If we hit this goto then the kernel will crash.
>
>   1873          }
>
>     [ snip ]
>
>   1916          /* Enable interrupt */
>   1917          xgene_pmu->ops->unmask_int(xgene_pmu);
>   1918
>   1919          return 0;
>   1920
>   1921  err:
>   1922          if (xgene_pmu->pcppmu_csr)
>   1923                  devm_iounmap(&pdev->dev, xgene_pmu->pcppmu_csr);
>   1924          devm_kfree(&pdev->dev, xgene_pmu);
>
> Can't we remove all this cleanup since it's devm_ managed resources?

Yes, you are right.
We can remove all this cleanup and also others because these managed
resources are automatically freed/unmapped on driver detach.

Hi Mark,

If you agree, I can post a patch to fix the issue.

[...]

Regards,
-- 
Tai